Discover opportunities to engage students in science, technology, engineering and math (STEM) with lessons and resources inspired by the latest happenings at NASA.

› Learn more and explore the collection



Collage of images and graphics from the InSight Mars lander mission. Links to full images and descriptions in caption.

As NASA retires its InSight Mars lander, here's a look at some of the biggest discoveries from the first mission designed to study the Red Planet's interior – plus, how to make connections to what students are learning now.


After more than four years listening to the “heartbeat” of Mars, NASA is saying goodbye to the InSight lander as the mission on the Red Planet comes to an end. On Dec. 21, 2022 scientists wrapped up the first-of-its-kind mission to study the interior of Mars as dust in the Martian atmosphere and on the spacecraft’s solar panels prevented the lander from generating enough power to continue.

Read on to learn how the mission worked, what it discovered, and how to bring the science and engineering of the mission into the classroom.

How It Worked

The lander is showin on the surface of Mars with a cutaway view of the Martian interior and core below the spacecraft. SEIS and HP3 are resting on the surface in front of the spacecraft and attached to InSight with long leash-like teathers. RISE juts out like a speaker from the flat top of the spacecraft between its two wing-like solar panels.

The locations of InSight's three main science tools, SEIS, HP3, and RISE are labeled in this illustration of the lander on Mars. | + Expand image | › Full image and caption

The InSight lander was designed to reveal the processes that led to the formation of Mars – as well as Earth, the Moon, and all rocky worlds. This meant meeting two main science goals.

First, scientists wanted to understand how Mars formed and evolved. To do that, they needed to investigate the size and make-up of Mars’ core, the thickness and structure of its crust, the structure of the mantle layer, the warmth of the planet's interior, and the amount of heat flowing through the planet.

Second, to study tectonic activity on Mars, scientists needed to determine the power, frequency, and location of “marsquakes” as well as measure how often meteoroids impacted the Red Planet, creating seismic waves.

Engineers equipped InSight with three main science tools that would allow researchers to answer these questions about Mars.

SEIS, a seismometer like the ones used on Earth to record earthquakes, measured the seismic waves on Mars. These waves, which travel through the Red Planet, can tell scientists a lot about the areas they pass through. They even carry clues about whether it was a marsquake or meteorite impact that created the waves.

InSight captured these images of clouds drifting in the distance, visible just beyond the dome-like top of the SEIS instrument. Credit: NASA/JPL-Caltech | + Expand image | › Full image and caption

InSight's Heat Flow and Physical Properties Package, or HP3, was an instrument designed to burrow 16 feet (five meters) into Mars to measure the temperature at different depths and monitor how heat flowed out toward the surface. However, the self-hammering probe, informally called the "mole," struggled to dig itself in due to the unexpected consistency of the top few inches of Mars regolith at the landing site. Using full-size models of the lander and probe, engineers recreated InSight’s environment here on Earth to see if they could find a solution to the issue. They tested solutions that would allow the probe to penetrate the surface, including pressing the scoop attached to InSight’s robotic arm against the probe. While the effort serves as a great real-world example of how engineers work through problems with distant spacecraft, ultimately, none of the solutions allowed the probe to dig past the surface when attempted on Mars.

In 2019, InSight mission scientist/engineer Troy Hudson shared the game plan for getting the mission's heat probe digging again on Mars. Ultimately, the team wasn't able to to get the "mole" working, but the effort is a great real-world example of how engineers work through problems with distant spacecraft. | Watch on YouTube

InSight’s third experiment, called RISE, used the spacecraft’s radio antennas to precisely measure the lander's position on the surface of Mars. The interior structure of Mars affects the planet’s motion, causing it to wobble. Measuring InSight’s position as the planet wobbled helped scientists gain a better understanding of the core and other layered structures that exist within the interior of Mars.

What We Discovered

A cutaway view of the interior of Mars shows a crust that is 0-25 mi (0-40 km) deep, an upper mantle that is 25-630 mi (40-1,015 km) deep; a transition zone that is 630-970 mi (1,015-1,560 km) deep, and a Core that is 970-2,105 mi (1,560-3,390 km) deep. Meteor impacts are shown as the sources of seismic activity. A separate inset shows InSight on the surface of a cutaway view of Mars' interior with lines representing Direct P, S waves extending from the upper mantle, through the curst, to SEIS on the surface.

Using its seismometer, InSight gained a deeper understanding of the interior layers of Mars, as detailed in this graphic. Image credit: NASA/JPL-Caltech | + Expand image | › Full image and caption

InSight’s instruments enabled the mission science team to gain an understanding of not only the depth of Mars’ crust, mantle, and core, but also the composition of those features. They also learned just how active Mars really is.

The Structure of Mars

Working our way from the surface to the center of the planet, scientists found Mars’ crust was thinner than expected. Seismic waves detected by SEIS indicate that the crust is made up of three sub-layers, similar to Earth’s crust. The top-most layer of the crust is about six miles (10 kilometers) deep, while the denser layers of the crust, which contain more felsic, or iron-rich, material extend downward to about 25 miles (40 kilometers) below the surface. As seismic waves from a marsquake or a meteorite impact spread across the surface and through the interior of the planet, they can reflect off of underground layers, giving scientists views into the unseen materials below. Measuring how the waves change as a result of these reflections is how scientists unveiled the underground structure of Mars.

Like Earth, Mars has a lithosphere, a rigid layer made up of the crust and upper mantle. The Martian lithosphere extends about 310 miles (500 kilometers) below the surface before it transitions into the remaining mantle layer, which is relatively cool compared with Earth’s mantle. Mars’ mantle extends to 969 miles (1,560 kilometers) below the surface where it meets the planet’s core.

The InSight lander is shown on the surface of Mars, where circular lines radiate out from a central point. The interior of Mars is shown with lines flowing left and right from the same central point and extending from the crust into Mars’ mantle down to its large central core. In the background, a cutaway shows the interior of Earth with more interior layers and a smaller core. Full problem text is available on the lesson page.

In this lesson from the "Pi in the Sky" math challenge, students use measurements from InSight along with pi to calculate the density of Mars' core. Image credit: NASA/JPL-Caltech | + Expand image | › Go to the lesson

Scientists measured the core of Mars and found it to be larger than expected, with a radius of 1,137 miles (1,830 kilometers). With this information, scientists were able to estimate the density of Mars' core, which turned out to be less dense than anticipated, meaning it contains lighter elements mixed in with iron. Scientists also confirmed that the planet contains a liquid core. While we know that Earth has a liquid outer core and solid inner core, scientists will need to further study the data returned from InSight to know if there is also a solid inner core on Mars.

As scientists continue to study the data returned from InSight, we could learn even more about how Mars formed, how its magnetic field developed, and what materials make up the core, which could ultimately help us better understand how Earth and other planets formed.

Marsquakes

InSight discovered that Mars is a very active planet. A total of 1,319 marsquakes were detected after the SEIS instrument was placed on the surface. The largest, which was estimated to be a magnitude 5, was detected in May of 2022.

Unlike Earth, where the crust is broken into large pieces called plates that continually shift around causing earthquakes, Mars’ crust is made up of one solid plate, somewhat like a shell. However, as the planet cools, the crust shrinks, creating breaks called faults. This breaking action is what causes marsquakes, and the seismic waves generated by the quakes are what help scientists figure out when and where the quakes occurred and how powerful they were.

A target symbol representing a marsquake appears on the other side of Mars from InSight. Pink and blue lines representing different waves extend around Mars from the left and right, respectively, of the epicenter. A green line extends from SEIS all the way around Mars and back to the instrument. An inset appears on top of SEIS that shows a recording of the wave measurements.

In this math problem from the "Pi in the Sky" series, students use pi to identify the timing and location of a hypothetical marsquake recorded by InSight. Image credit: NASA/JPL-Caltech | + Expand image | › Go to the lesson

Nearly all of the strongest marsquakes detected by InSight came from a region known as Cerberus Fossae, a volcanic region that may have had lava flows within the past few million years. Volcanic activity, even without lava flowing on the surface, can be another way marsquakes occur. Images from orbiting spacecraft show boulders that have fallen from cliffs in this region, perhaps shaken loose by large marsquakes.

This seismogram shows the largest quake ever detected on another planet. Estimated at magnitude 5, this quake was discovered by InSight on May 4, 2022. Listen to a sonification of this seismogram. | + Expand image | › Full image and caption

Conversely, InSight didn't detect any quakes in the volcanic region known as Tharsis, the home of three of Mars’ largest volcanos that sit approximately one-third of the way around the planet from InSight. This doesn’t necessarily mean the area is not seismically active. Scientists think there may be quakes occurring, but the size of Mars’ liquid core creates what’s known as a shadow zone – an area into which seismic waves don’t pass – at InSight's location.

Meteorite Impacts

On Sept. 5, 2021, InSight detected the impacts of a meteoroid that entered the Martian atmosphere. The meteoroid exploded into at least three pieces that reached the surface and left behind craters. NASA’s Mars Reconnaissance Orbiter passed over the impact sites to capture images of the three new craters and confirm their locations.

A direct overhead view of a light-gray-colored cratered surface is interrupted by three black splotches of increasing size from left to right. At the center of each dark scar is a royal blue splotch. The surface around the blue center looks as if it's been sprayed with a dark material that extends farther on the right side of each crater than on the left.

This image, captured by the Mars Reconnaissance Orbiter, shows the craters (in blue) formed by a meteroid impact on Mars on Sept. 5, 2021. The impact was the first to be detected by InSight. Image credit: NASA/JPL-Caltech/University of Arizona | + Expand image | › Full image and caption

“After three years of waiting for an impact, those craters looked beautiful,” said Ingrid Daubar of Brown University, a Mars impacts specialist.

Mars’ thin atmosphere, which is less than 1% as dense as Earth’s, means meteoroids have a better chance of not disintegrating in the heat and pressure that builds up as they pass through the atmosphere to the planet’s surface. Despite this fact and Mars' proximity to the asteroid belt, the planet proved to be a challenging location to detect meteorite impacts because of "noise" in the data created by winds blowing on SEIS and seasonal changes in the atmosphere.

With the confirmation of the September 2021 impacts, scientists were able to identify a telltale seismic signature to these meteorite impacts. With this information in hand, they looked back through InSight's data and found three more impacts – one in 2020 and two in 2021. Scientists anticipate finding even more impacts in the existing data that might have been hidden by the noise in the data.

Three overhead images of a brown cratered surfaces with a bright blue-colored crater at the center. Surrounding the crater in each image is a splotch of different colored material sprayed out in all directions.

This collage shows three other meteoroid impacts on Mars that were detected by the seismometer on InSight and captured by the Mars Reconnaissance Orbiter. Image credit: Credit: NASA/JPL-Caltech/University of Arizona | + Expand image | › Full image and caption

Meteorite impacts are an invaluable piece of understanding the planet’s surface. On a planet like Earth, wind, rain, snow and ice wear down surface features in a process known as weathering. Plate tectonics and active volcanism refresh Earth’s surface regularly. Mars’ surface is older and doesn't go through those same processes, so a record of past geologic events like meteorite impacts is more apparent on the planet's surface. By counting impact craters visible on Mars today, scientists can update their models and better estimate the number of impacts that occurred in the early solar system. This gives them an improved approximation of the age of the planet’s surface.

Learn how InSight detected the first seismic waves from a meteoroid on Mars and how the lander captured the sound of the space rock striking the surface. | Watch on YouTube

Why It's Important

Before InSight touched down, all Mars missions – landers, rovers, orbiters and flyby spacecraft – studied the surface and atmosphere of the planet. InSight was the first mission to study the deep interior of Mars.

Even with the InSight mission drawing to a close, the science and engineering of the mission will continue to inform our understanding of the Red Planet and our solar system for years as researchers further examine the data returned to Earth. Keep up to date with the latest findings from InSight scientists and engineers on the mission website.

Teach It

Explore these lessons in geology, physics, math, coding and engineering to connect student learning to the InSight mission and the real-world STEM that happens at NASA.

Educator Resources

Student Activities

Explore More

TAGS: K-12 Education, Classrooms, Teaching, Teachers, Resources, Teachable Moments, Mars, InSight, Missions, Spacecraft, Marsquakes

  • Lyle Tavernier
READ MORE

A rectangular box-shaped spacecraft with long arms extending from either side. Above the arms are wing-like solar panels extending in the opposite direction. The curvature of Earth and wispy clouds are depicted just below the spacecraft.

Explore how and why the SWOT mission will take stock of Earth's water budget, what it could mean for assessing climate change, and how to bring it all to students.

Update: Dec. 15, 2022 – NASA, the French space agency, and SpaceX are now targeting 3:46 a.m. PST (6:46 a.m. EST) on Friday, Dec.16, for the launch of the Surface Water and Ocean Topography (SWOT) satellite. Visit NASA's SWOT launch blog for the latest updates.


NASA is launching an Earth-orbiting mission that will map the planet’s surface water resources better than ever before. Scheduled to launch on Dec. 16 from Vandenberg Space Force Base in California, the Surface Water and Ocean Topography, or SWOT mission is the latest international collaboration designed to monitor and report on our home planet. By providing us with a highly detailed 3D view of rivers, lakes, and oceans, SWOT promises to improve our understanding of Earth’s water cycle and the role oceans play in climate change, as well as help us better respond to drought and flooding.

Read on to find out why we're hoping to learn more about Earth's surface water, get to know the science behind SWOT's unique design, and follow along with STEM teaching and learning resources.

Why It's Important

Observing Earth from space provides scientists with a global view that is important for understanding the whole climate system. In the case of SWOT, we will be able to monitor Earth’s surface water with unprecedented detail and accuracy. SWOT will provide scientists with measurements of water volume change and movement that will inform our understanding of fresh water availability, flood hazards, and the mechanisms of climate change.

Scientists and engineers provide an overview of the SWOT mission. Credit: NASA/JPL-Caltech | Watch on YouTube

Water Flow

Scientists use a variety of methods to track Earth’s water. These include stream and lake gauges and even measurements from space such as sea surface altimetry and gravitational measurements of aquifer volumes. Monitoring of river flow and lake volume is important because it can tell us how much freshwater is readily available and at what locations. River flow monitoring can also help us make inferences about the downstream environmental impact. But monitoring Earth’s surface water in great detail with enough frequency to track water movement has proven challenging. Until now, most monitoring of river flow and lake levels has relied on water-flow and water-level gauges placed across Earth, which requires that they be accessible and maintained. Not all streams and lakes have gauges and previous space-based altimetry and gravitational measurements, though useful for large bodies of water, have not been able to adequately track the constant movement of water through smaller rivers or lakes.

Here's why understanding Earth’s "water budget" is an important part of understanding our planet and planning for future water needs.

SWOT will be able to capture these measurements across the globe in 3D every 21 days. The mission will monitor how much water is flowing through hundreds of thousands of rivers wider than 330 feet (100 meters) and keep a close watch on the levels of more than a million lakes larger than 15 acres (6 hectares). Data from the mission will be used to create detailed maps of rivers, lakes, and reservoirs that will enable accurate monitoring to provide a view of freshwater resources that is not reliant on physical access. Meanwhile, SWOT’s volumetric measurements of rivers, lakes, and reservoirs will help hydrologists better track drought and flooding impacts in near-real-time.

Coastal Sea Level Rise

SWOT will measure our oceans with unprecedented accuracy, revealing details of ocean features as small as 9 miles (15 kilometers) across. SWOT will also monitor sea levels and tides. Though we have excellent global sea level data, we do not have detailed sea level measurements near coastlines. Coastal sea levels vary across the globe as a result of ocean currents, weather patterns, land changes, and other factors. Sea levels are rising faster than ever, and higher sea levels also mean that hurricane storm surges will reach farther inland than ever before, causing substantially more damage than the same category of hurricanes in the past. SWOT will be able to monitor coastal sea level variations and fill gaps in the observations we currently have from other sources.

What is sea level rise and what does it mean for our planet? | › View Transcript

Ocean Heat Sinks

Further contributing to our understanding of the role Earth’s oceans play in climate change, SWOT will explore how the ocean absorbs atmospheric heat and carbon, moderating global temperatures and climate change. Scientists understand ocean circulation on a large scale and know that ocean currents are driven by temperature and salinity differences. However, scientists do not currently have a good understanding of fine-scale ocean currents, where most of the ocean's motion-related energy is stored and lost. Circulation at these fine scales is thought to be responsible for transporting half of the heat and carbon from the upper ocean to deeper layers. Such downward ocean currents have helped to mitigate the decades-long rise in global air temperatures by absorbing and storing heat and carbon away from the atmosphere. Knowing more about this process is critical for understanding the mechanisms of global climate change.

JPL scientist Josh Willis uses a water balloon to show how Earth's oceans are absorbing most of the heat being trapped on our warming world. | › Related lesson

These fine-scale ocean currents also transport nutrients to marine life and circulate pollutants such as crude oil and debris. Understanding nutrient transport helps oceanographers assess ocean health and the productivity of fisheries. And tracking pollutants aids in natural hazard assessment, prediction, and response.

How It Works

A joint effort between NASA and the French space agency – with contributions from the Canadian and UK space agencies – SWOT will continue NASA’s decades-long record of monitoring sea surface height across the globe. But this mission will add a level of detail never before achieved.

SWOT will measure more than 90% of Earth’s surface water, scanning the planet between 78°N latitude and 78°S latitude within 1 centimeter of accuracy and retracing the same path every 21 days. Achieving this level of accuracy from a spacecraft height of 554 miles (891 kilometers) requires that the boom using radar to measure water elevation remain stable within 2 microns – or about 3% of the thickness of a human hair.

This visualization shows ocean surface currents around the world during the period from June 2005 through December 2007. With its new, high resolution wide-swath measurements, SWOT will be able to observe eddies and current features at greater resolution than previously possible. Credit: NASA Scientific Visualization Studio | Watch on YouTube

Prior to SWOT, spacecraft have used conventional nadir, or straight-down, altimetry to measure sea surface height. Conventional nadir altimetry sends a series of radar or laser pulses down to the surface and measures the time it takes for each signal to return to the spacecraft, thus revealing distances to surface features. To acquire more detailed information on surface water, SWOT will use an innovative instrument called the Ka-band Radar Interferometer, or KaRIn, to measure water height with exceptional accuracy. Ka-band is a portion of the microwave part of the electromagnetic spectrum. SWOT uses microwaves because they can penetrate clouds to return data about water surfaces.

A radar signal is sent straight down from the SWOT spacecraft as it flies over Earth. Beams are shown bouncing back to receivers on either side of the spacecraft. The section of Earth measured by the spacecraft is shown as two side-by-side tracks colored in as a heatmap. The camera zooms out to show these tracks criscrossing the planet and eventually covering a majority of the surface.

SWOT will track Earth's surface water in incredible detail using an innovative instrument called the Ka-band Radar Interferometer, or KaRIn. Image credit: NASA/JPL-Caltech | + Expand image

The KaRIn instrument uses the principles of synthetic aperture radar combined with interferometry to measure sea surface height. A radar signal is emitted from the end of the 10-meter-wide boom on the spacecraft. The reflected signal is then received by antennas on both ends of the boom, capturing data from two 30-mile (50-kilometer) wide swaths on either side of the spacecraft. The received signals will be slightly out of sync, or phase, from one another because they will travel different distances to return to the receivers on either end of the boom. Knowing the phase difference, the distance between the antennas, and the radar wavelength allows us to calculate the distance to the surface.

The first of three images shows two paths of different lengths extending diagonally from a point on Earth’s surface to receivers on either side of the SWOT spacecraft. A second image shows the paths as light waves that are slightly out of phase. The third image shows a line drawn directly from the rightmost receiver to the path leading to the leftmost receiver, such that the intersected paths from Earth are equal in length. The upper triangle formed by this intersection has a short leg, highlighted in yellow, that represents the remaining length of the leftmost path. The yellow short leg represents the range difference between the two paths from Earth.

Radar signals bounced off the water’s surface will be received by antennas on both ends of SWOT's 10-meter-wide boom. The received signals will be slightly out of phase because they will travel different distances as they return to the receivers. Scientists use this phase difference and the radar wavelength to calculate the distance to the surface. Image credit: NASA/JPL-Caltech | + Expand image

The observations acquired by the two antennas can be combined into what is known as an interferogram. An interferogram is a pattern of wave interference that can reveal more detail beyond the 1-centimeter resolution captured by the radar. To explain how it works, we'll recall a couple of concepts from high school physics. When out-of-phase waves from the two antennas are combined, constructive and destructive interference patterns result in some wave crests being higher and some wave troughs being lower than those of the original waves. The patterns that result from the combination of the waves reveal more detail with resolution better than the 1-centimeter wavelength of the original Ka-band radar waves because the interference occurs over a portion of a wavelength. An interferogram can be coupled with elevation data to reveal a 3D representation of the water’s surface.

A diagram illustrating the swaths of data that SWOT will collect, including labels for the following: 10 m baseline between SWOT's receivers; a distance of 891 km between the surface and Interferometer Antenna 1; Interferometer Left Swath resulting in ocean topography with an H-Pol swath of 10-60 km; Interferometer Right Swath resulting in surface water topography with a V-Pol of 10-60 km; a straight-down Nadir Altimeter path directly below the spacecraft in the gap between the swaths; a cross-track resolution from 70m to 10m.

The KaRIn instrument illuminates two parallel tracks of approximately 50 kilometres on either side of a nadir track from a traditional altimeter. The signals are received by two antennas 10 metres apart and are then processed to yield interferometry measurements. Image credit: NASA/JPL-Caltech | + Expand image

This highly accurate 3D view of Earth’s surface water is what makes SWOT so unique and will enable scientists to more closely monitor the dynamics of the water cycle. In addition to observing ocean currents and eddies that will inform our understanding of the ocean’s role in climate change, SWOT's use of interferometry will allow scientists to track volumetric changes in lakes and quantify river flooding, tasks that cannot yet be done on a wide scale in any other way.

A colorful swath of yellows, oranges, magentas, purples is overlaid horizontally on a satellite image of desert landscape with thin yellow and red lines cutting diagonally across the image. On the center-left of the image, the colors fan out like a rainbow sprinkler. On the left side of the swath are a cluster of yellow dots.

This interferogram was captured by the air-based UAVSAR instrument of the magnitude 7.2 Baja California earthquake of April 4, 2010. The interferogram is overlaid atop a Google Earth image of the region. Image credit: NASA/JPL/USGS/Google | › Learn more

Follow Along

SWOT is scheduled to launch no earlier than Dec. 16, 2022, on a SpaceX Falcon 9 rocket from Vandenberg Space Force Base in California. Tune in to watch the launch on NASA TV.

After launch, the spacecraft will spend 6-months in a calibration and validation phase, during which it will make a full orbit of Earth every day at an altitude of 553 miles (857 kilometers). Upon completion of this phase, SWOT will increase its altitude to 554 miles (891 kilometers) and assume a 21-day repeat orbit for the remainder of its mission.

Visit the mission website to follow along as data are returned and explore the latest news, images, and updates as SWOT provides a new view on one of our planet's most important resources.

Teach It

The SWOT mission is the perfect opportunity to engage students in studying Earth’s water budget and water cycle. Explore these lessons and resources to get students excited about the STEM involved in studying Earth’s water and climate change from space.

Educator Resources

Student Activities

Explore More

Activities for Kids

Websites

Facts & Figures

Videos

Interactives

Image Gallery

Articles

Podcast

TAGS: K-12 Education, Teachers, Educators, Earth Science, Earth, Climate Change, Climate, Satellites, Teachable Moments

  • Ota Lutz
READ MORE

A long boom extends from a cylindrical telescope floating above Earth. At the end of the spacecraft's boom are three converging circular mirrors, like petals on a flower.

A NASA space telescope mission is giving astronomers a whole new way to peer into the universe, allowing us to uncover long-standing mysteries surrounding objects such as black holes. Find out how it works and how to engage students in the science behind the mission.


Some of the wildest, most exciting features of our universe – from black holes to neutron stars – remain mysteries to us. What we do know is that because of their extreme environments, some of these emit highly energetic X-ray light, which we can detect despite the vast distances between us and the source.

Now, a NASA space telescope mission is using new techniques to not only scout out these distant phenomena, but also provide new information about their origins. Read on to learn how scientists are getting exciting new perspectives on our universe and what the future of X-ray astronomy holds.

How They Did It

In 2021, NASA launched the Imaging X-Ray Polarimeter Explorer, or IXPE, through a collaboration with Ball Aerospace and the Italian Space Agency. The space telescope is designed to operate for two years, detecting X-rays emitted from highly energetic objects in space, such as black holes, different types of neutron stars (e.g., pulsars and magnetars) and active galactic nuclei. In its first year, the telescope is focusing on roughly a dozen previously studied X-ray sources, spending hours or even days observing each target to reveal new data made possible by spacecraft's scientific instruments.

IXPE isn't the first telescope to observe the universe in X-ray light. NASA's Chandra X-ray Observatory, launched in 1999, has famously spent more than 20 years photographing our universe at a wavelength of light exclusively found in high-energy environments, such as where cosmic materials are heated to millions of degrees as a result of intense magnetic fields or extreme gravity.

Using Chandra, scientists can assign colors to the different energy levels, or wavelengths, produced by these environments. This allows us to get a picture of the highly energetic light ejected by black holes and tiny neutron stars – small, but extremely dense stars with masses 10-25 times that of our Sun. These beautiful images, such as from Chandra’s first target, Cassiopeia A (Cas A for short), show the violent beauty of stars exploding.

A blue halo of squiggly lines surrounds an explosion of colors extending out from the center of the supernova. Closest to the center is a circular splatter of orange surrounded by green and yellow and finally a hazy purple.

This image of the supernova Cassiopeia A from NASA’s Chandra X-ray Observatory shows the location of different elements in the remains of the explosion: silicon (red), sulfur (yellow), calcium (green) and iron (purple). Each of these elements produces X-rays within narrow energy ranges, allowing maps of their location to be created. Image credit: NASA/CXC/SAO | › Full image and caption

While Chandra has earned its name as one of “The Great Observatories,” astronomers have long desired to peer further into highly energetic environments in space by capturing them in even more detail.

IXPE expands upon Chandra’s work with the introduction of a tool called a polarimeter, an instrument used to understand the shape and direction of the light that reaches the space telescope's detectors. The polarimeter on IXPE allows scientists to gain insight into the finer details of black holes, supernovas, and magnetars, like which direction they are spinning and their three-dimensional shape.

A blue halo of squiggly lines surrounds a fuzzy donut-shaped haze of magenta with splatters of blue and white throughout.

This image of Cassiopeia A was created using some of the first X-ray data collected by IXPE, shown in magenta, combined with high-energy X-ray data from Chandra, in blue. Image credit: NASA/CXC/SAO/IXPE | › Full image and caption

While scientists have just begun putting IXPE's capabilities to use, they're already starting to reveal new details about the inner workings of these objects – such as the magnetic field environment around Cas A, shown in a newly released image.

The supernova remnant is shown as a blob of blue with swirls of brighter blues and large splatters of white. Dashed lines on top of the image flow from the center outward. Dividing the supernova and lines into quarter sections of a circle, the top right section has lines that flow directly northeast. The section at the bottom right has lines that flow nearly southeast but curve northwards slightly The section at the bottom left has lines that flow straight up from the bottom edge of the supernova, curve around the center and then flow back down. And the section at the top left has lines that flow from the center directly west, others that curve around the center and flow diagonally northwest and others that flow from the center to the north. Small sections of the lines are highlighted in green at the 1 o'clock, 2 o'clock, 4 o'clock, 7 o'clock and 11 o'clock portions of the supernova.

The lines in this newly released image come from IXPE measurements that show the direction of the magnetic field across regions of Cassiopeia A. Green lines indicate regions where the measurements are most highly significant. These results indicate that the magnetic field lines near the outskirts of the supernova remnant are largely oriented radially, i.e., in a direction from the center of the remnant outwards. The IXPE observations also reveal that the magnetic field over small regions is highly tangled, without a dominant preferred direction. Observations such as this one can help scientists learn how particles shooting out from supernovae interact with the magnetic field created by the explosion. Image credits: X-ray: Chandra: NASA/CXC/SAO; IXPE: NASA/MSFC/J. Vink et al. | + Expand image | › Full image and caption

“For the first time, we will use every collected photon of light to tell us about the nature and shapes of objects in the sky that would be dots of light otherwise,” says Roger Romani, a Stanford professor and the co-investigator on IXPE.

How It Works

Generally, when light is produced, it is what we call unpolarized, meaning that it oscillates in every direction. For example, our Sun produces unpolarized light. But sometimes, light is produced in a highly organized fashion, oscillating only in one direction. In astronomy, this arises when magnetic fields force particles to incredibly high speeds, creating highly organized, or polarized, light.

This is what makes objects like the supernova Cas A such enticing targets for IXPE. Exploded stars like Cas A generate massive energetic waves when they go supernova, giving scientists a view of how particles shooting out at immense speeds interact with the magnetic fields from such an event. In the case of Cas A, IXPE was able to determine that the x-rays are not very polarized, meaning the explosion created very turbulent regions with multiple field directions.

While the idea of polarized or organized light may sound abstract, you may have noticed it the last time you were outside on a sunny day. If you’ve tried on a pair of polarized sunglasses, you may have noticed that the glare was greatly reduced. That’s because as light scatters, it bounces off of reflective surfaces in all directions. However, polarized lenses have tiny filters that only allow light coming from a narrow band of directions to pass through.

The polarimeter on IXPE works in a similar way. Astronomers can determine the strength of an object's magnetic field by using the polarimeter to measure how much of the light detected by the telescope is polarized. Typically, the more polarized the light the stronger the magnetic field at the source.

Astronomers can even go a step further to measure the direction this light is oscillating by measuring the angle of the light that reaches the telescope. Because the polarized light leaves the source in a predictable fashion – namely perpendicular from its magnetic field – knowing the angle of the oscillating light provides information about the axis of rotation and potentially even the surface structure of objects such as neutron stars and nebulae.

Side by side animations showing a rope moving from side to side through an open window and a rope moving up and down through an open window. As the window closes, fewer of the waves in the rope moving up and down make it through the window whereas the rope moving from side to side is undisturbed.

In this demonstration, the rope represents light waves and the open window represents a polarimeter. Depending on the angle of the light waves (rope), more or less information makes it through the polarimeter (window) the narrower it is. By measuring the amount of light received through the polarimeter, IXPE can determine the angle and the polarization of the light. Image credit: NASA/JPL-Caltech | + Expand image

Imagine, for example, that you were holding one end of a piece of rope secured to an object at the other end. If you swung the rope side to side to make horizontal waves, those waves would be able to make it through a narrow target like a window. If you started to shut the window from the top, narrowing the opening, the waves could conceivably still make it through the opening. However, if you made veritcal waves by waving the rope up and down, as the window closed, fewer and fewer waves would make it through the opening. Likewise, by measuring the light that makes it through the polarimeter to the detector on the other side, IXPE can determine the angle of the light received.

To collect this light, IXPE uses three identical mirrors at the end of a four meter (13 foot) boom. The light received by IXPE is carefully focused on the spacecraft’s polarimeter at the other end of the boom, allowing scientists to collect those crucial measurements.

During the IXPE launch broadcast, commentators discuss the components of the spacecraft and how it measures polarization. | Watch on YouTube

Why It's Important

Building on Chandra's observations from the past two decades, IXPE's novel approach to X-ray science is pulling the curtain back even farther on some of the most fascinating objects in the universe, providing first looks at how and where radiation is being produced in some of the most extreme environments in the universe. IXPE's measurements of Cas A are just the beginning, with even more mysterious targets ready to be explored.

Take it from Martin Weisskopf, the principal scientist on IXPE and project scientist for Chandra, who has spent his 50-year career working in X-ray astronomy, who says, “IXPE will open up the field in ways we’ve been stuck only theorizing about."

Teach It

Explore more on how NASA uses light to map our universe, and dig deeper into some of the celestial features it allows to study, such as blackholes and neutron stars.

Activities

Educator Resources

Explore More


NASA's Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: Universe, Stars and Galaxies, Space Telescope, IXPE, Astronomy, Science, Electromagnetic Spectrum

  • Brandon Rodriguez
READ MORE

Find out more about the historic first test, which could be used to defend our planet if a hazardous asteroid were discovered. Plus, explore lessons to bring the science and engineering of the mission into the classroom.


Update: Oct. 20, 2022 – The DART spacecraft successfully impacted the asteroid Dimorphos on September 26, reducing the period of the asteroid's orbit by 32 minutes. Scientists considered a change of 73 seconds to be the minimum amount for success. This article has been updated to reflect the latest data and images from the impact.


In a successful attempt to alter the orbit of an asteroid for the first time in history, NASA crashed a spacecraft into the asteroid Dimorphos on Sept. 26, 2022. The mission, known as the Double Asteroid Redirection Test, or DART, took place at an asteroid that posed no threat to our planet. Rather, it was an ideal target for NASA to test an important element of its planetary defense plan.

Read further to learn about DART, how it worked, and how the science and engineering behind the mission can be used to teach a variety of STEM topics.

Why It's Important

The vast majority of asteroids and comets are not dangerous, and never will be. Asteroids and comets are considered potentially hazardous objects, or PHOs, if they are 100-165 feet (30-50 meters) in diameter or larger and their orbit around the Sun comes within five million miles (eight million kilometers) of Earth’s orbit. NASA's planetary defense strategy involves detecting and tracking these objects using telescopes on the ground and in space. In fact, NASA’s Center for Near Earth Object Studies, or CNEOS, monitors all known near-Earth objects to assess any impact risk they may pose. Any relatively close approach is reported on the Asteroid Watch dashboard.

Six triangular sections fan out from a shadowed view of Earth describing the PDCO's various activities, including 'Search, Detect & Track', 'Characterize', 'Plan and Coordinate', 'Mitigate', and 'Assess'.

NASA's Planetary Defense Coordination Office runs a variety of programs and initiatives aimed at detecting and responding to threats from potentially hazardous objects, should one be discovered. The DART mission is one component and the first mission being flown by the team. Image credit: NASA | + Expand image

While there are no known objects currently posing a threat to Earth, scientists continue scanning the skies for unknown asteroids. NASA is actively researching and planning for ways to prevent or reduce the effects of a potential impact, should one be discovered. The DART mission was the first test of such a plan – in this case, whether it was possible to divert an asteroid from its predicted course by slamming into it with a spacecraft.

Eyes on Asteroids is a real-time visualization of every known asteroid or comet that is classified as a near-Earth object, or NEO. Asteroids are represented as blue dots and comets as shown as white dots. Use your mouse to explore the interactive further and learn more about the objects and how we track them. Credit: NASA/JPL-Caltech | Explore the full interactive

With the knowledge gained from the demonstration, similar techniques could be used in the future to deflect an asteroid or comet away from Earth if it were deemed hazardous to the planet.

How It Worked

With a diameter of about 525 feet (160 meters) – the length of 1.5 football fields – Dimorphos is the smaller of two asteroids in a double-asteroid system. Before DART's impact, Dimorphos orbited the larger asteroid called Didymos (Greek for "twin"), every 11 hours and 55 minutes.

Various Earth objects are shown to scale ranging from a bus at 14 meters to the Burj Khalifa skyscraper at 830 meters. Dimorphos at 163 meters is shown between the Statue of Liberty (93 meters) on its left and the Great Pyramid of Giza (139 meters) on its right. Didymos is shown between the One World Trade Center (546 meters) on its left and the Burj Khalifa on its right.

The sizes of the two asteroids in the Didymos system relative to objects on Earth. Image credit: NASA/Johns Hopkins APL | + Expand image

Neither asteroid poses a threat to our planet, which is one reason why this asteroid system was the ideal place to test asteroid redirection techniques. At the time of DART's impact, the asteroid pair was 6.8 million miles (11 million kilometers) away from Earth as they traveled on their orbit around the Sun.

The DART spacecraft was designed to collide head-on with Dimorphos to alter its orbit, shortening the time it takes the small asteroid to travel around Didymos. Compared with Dimorphos, which has a mass of about 11 billion pounds (five billion kilograms), the DART spacecraft was light. It weighed just 1,210 pounds (550 kilograms) at the time of impact. So how did such a light spacecraft affect the orbit of a relatively massive asteroid?

You can use your mouse to explore this interactive view of DART's impact with Dimorphos from NASA's Eyes on the Solar System. Credit: NASA/JPL-Caltech | Explore the full interactive

DART was designed as a kinetic impactor, meaning it transferred its momentum and kinetic energy to Dimorphos upon impact, altering the asteroid's orbit in return. Scientists were able to make predictions about some of these effects thanks to principles described in Newton's laws of motion.

Newton’s first law told us that the asteroid’s orbit would remain unchanged until something acted upon it. Using the formula for linear momentum (p = m * v), we could calculate that the spacecraft, which at the time of impact would be traveling at 3.8 miles (6.1 kilometers) per second, would have about 0.5% of the asteroid’s momentum. The momentum of the spacecraft may seem small in comparison, but calculations suggested it would be enough to make a detectable change in the speed of Dimorphos' orbit. However, mission planners felt that changing Dimorphos’ orbit by at least 73 seconds would be enough to consider the test a success.

But there was more to consider in testing whether the technique could be used in the future for planetary defense. For example, the formula for kinetic energy (KE = 0.5 * m * v2) tells us that a fast moving spacecraft possesses a lot of energy.

When DART hit the surface of the asteroid, its kinetic energy was 10 billion joules! A crater was formed and material known as ejecta was blasted out as a result of the impact. Scientists are still studying the data returned from the mission to determine the amount of material ejected out of the crater, but estimates prior to impact put the number at 10-100 times the mass of the spacecraft itself. The force needed to push this material out was then matched by an equal reaction force pushing on the asteroid in the opposite direction, as described by Newton’s third law.

This animation shows conceptually how DART's impact is predicted to change Dimorphos' orbit from a larger orbit to a slightly smaller one that's several minutes shorter than the original. Credit: NASA/Johns Hopkins APL/Jon Emmerich | Watch on YouTube

How much material was ejected and its recoil momentum is still unknown. A lot depends on the surface composition of the asteroid, which scientists are still investigating. Laboratory tests on Earth suggested that if the surface material was poorly conglomerated, or loosely formed, more material would be blasted out. A surface that was well conglomerated, or densely compacted, would eject less material.

After the DART impact, scientists used a technique called the transit method to see how much the impact changed Dimorphos' orbit. As observed from Earth, the Didymos pair is what’s known as an eclipsing binary, meaning Dimorphos passes in front of and behind Didymos from our view, creating what appears from Earth to be a subtle dip in the combined brightness of the pair. Scientists used ground-based telescopes to measure this change in brightness and calculate how quickly Dimorphos orbits Didymos. By comparing measurements from before and after impact, scientists determined that the orbit of Dimorphos had slowed by 32 minutes to 11 hours and 23 minutes.

A pixelated black and white image is labeled 2022 Oct 04 11:55:39 UTC and shows a thin circular line representing Dimorphos' orbit. On the line are two semi-transparent circles colored green and blue. The blue circle is at about the 9 o'clock position on the orbit. The green circle is at about the 12 o'clock position. A second similar image to the right has smaller pixels and appears to be a slightly more distant view. The image on the right is labled 2022 Oct 09 10:56:47 UTC. In the image on the right, the blue circle is also at the 9 o'clock position on the orbit, but the green circle is at the 6 o'clock position. A key on the far right of the image identifies the green circle as Dimorphos, the blue circle as Expected Dimorphos from previous 11 hr.55 min. orbit, and the line as Dimorphos orbit.

The green circle shows the location of the Dimorphos asteroid, which orbits the larger asteroid, Didymos, seen here as the bright line across the middle of the images. The blue circle shows where Dimorphos would have been had its orbit not changed due to NASA’s DART mission purposefully impacting the smaller asteroid on Sept. 26, 2022. The images were obtained from the NASA Jet Propulsion Laboratory’s Goldstone planetary radar in California and the National Science Foundation’s Green Bank Observatory in West Virginia. Image credit: NASA/Johns Hopkins APL/JPL/NASA JPL Goldstone Planetary Radar/National Science Foundation’s Green Bank Observatory | + Expand image | › DART image gallery

One of the biggest challenges of the DART mission was navigating a small spacecraft to a head-on collision with a small asteroid millions of miles away. To solve that problem, the spacecraft was equipped with a single instrument, the DRACO camera, which worked together with an autonomous navigation system called SMART Nav to guide the spacecraft without direct control from engineers on Earth. About four hours before impact, images captured by the camera were sent to the spacecraft's navigation system, allowing it to identify which of the two asteroids was Dimorphos and independently navigate to the target.

Two white points of light are circled in a fuzzy field of stars. The slightly larger point of light near the far right of the image is labeled Didymos.

A composite of 243 images of Didymos and Dimorphos taken by the DART spacecraft's DRACO camera on July 27, 2022, as the spacecraft was navigating to its target. Image credit: JPL DART Navigation Team | + Expand image | › DART image gallery

DART was not just an experimental asteroid impactor. The mission also used cutting-edge technology never before flown on a planetary spacecraft and tested new technologies designed to improve how we power and communicate with spacecraft.

Learn more about the engineering behind the DART mission, including the innovative Roll Out Solar Array and NEXT-C ion propulsion system, in this video featuring experts from the mission. Credit: APL | Watch on YouTube

One such technology that was first tested on the International Space Station and was later used on the solar-powered DART spacecraft, is the Roll Out Solar Array, or ROSA, power system. As its name suggests, the power system consisted of flexible solar panel material that was rolled up for launch and unrolled in space.

The Roll Out Solar Array, shown in this animated image captured during a test on the International Space Station, is making its first planetary journey on DART. Image credit: NASA | + Expand image

Some of the power generated by the solar array was used for another innovative technology, the spacecraft's NEXT-C ion propulsion system. Rather than using traditional chemical propulsion, DART was propelled by charged particles of xenon pushed from its engine. Ion propulsion has been used on other missions to asteroids and comets including Dawn and Deep Space 1, but DART's ion thrusters had higher performance and efficiency.

Follow Along

In the days following the event, NASA received images of the impact from a cubesat, LICIACube, that was deployed by DART before impact. The cubesat, which was provided by the Italian Space Agency, captured images of the impact and the ejecta cloud.

A flash of bright white with tendrils extending in all directions eminates from a more defined bright white blob. Overlapping rectangles show the object and ejecta in increasing contrast the closer they get to the center of the scene.

This image from LICIACube shows plumes of ejecta streaming from Dimorphos after DART's impact. Each rectangle represents a different level of contrast to better see fine structure in the plumes. By studying these streams of material, scientists will be able to learn more about the asteroid and the impact process. | + Expand image | › DART image gallery

Meanwhile, the James Webb Space Telescope, the Hubble Space Telescope, and the Lucy spacecraft observed Didymos to monitor how soon reflected sunlight from the ejecta plume could be seen. Going forward, DART team members will continue observing the asteroid system to measure the change in Dimorphos’ orbit and determine what happened on its surface. And in 2024, the European Space Agency plans to launch the Hera spacecraft to conduct an in-depth post-impact study of the Didymos system.

A starburst shape colored red grows in size and then contracts.

This animation, a timelapse of images from NASA’s James Webb Space Telescope, covers the time spanning just before DART's impact at 4:14 p.m. PDT (7:14 p.m. EDT) on Septtember 26 through 5 hours post-impact. Plumes of material from a compact core appear as wisps streaming away from where the impact took place. An area of rapid, extreme brightening is also visible in the animation. Image credit: Science: NASA, ESA, CSA, Cristina Thomas (Northern Arizona University), Ian Wong (NASA-GSFC); Joseph DePasquale (STScI) | + Expand image | › DART image gallery

Continue following along with all the science from DART, including the latest images and updates on the mission website. Plus, explore even more resources on this handy page.

Teach It

The mission is a great opportunity to engage students in the real world applications of STEM topics. Start exploring these lessons and resources to get students engaging in STEM along with the mission.

Educator Guides

Expert Talks

Student Activities

Articles

Resources for Kids

Check out these related resources for kids from NASA Space Place:

Explore More

TAGS: Asteroids and Comets, DART, near-Earth objects, planetary defense, Science, K-12 Education, Teachers, Educators, Parents, Teachable Moments

  • Lyle Tavernier
READ MORE

Animation showing a total lunar eclipse. Credit: NASA Goddard Media Studios

There’s no better time to learn about the Moon than during a lunar eclipse. Here’s how eclipses work, what to expect, and how to get students engaged.

This article has been updated to include information about the visibility and timing of the total lunar eclipse on Nov. 8, 2022. See What to Expect for details.


A full moon is always a good reason to go outside and look up, but a total or partial lunar eclipse is an awe-inspiring site that gives students a great opportunity to engage in practical sky watching. Whether it’s the Moon's reddish hue during a total lunar eclipse or the "bite" taken out of the Moon during a partial lunar eclipse, there's always something exciting to observe during these celestial events.

Read on to see what to expect during the next lunar eclipse. Plus, explore resources you can use at home or in the classroom to teach students about moon phases, craters, and more!

How It Works

Side-by-side images showing how the Moon, Sun and Earth align during an lunar eclipse versus a standard full moon

These side-by-side graphics show how the Moon, Sun, and Earth align during a lunar eclipse (left) versus a non-eclipse full moon (right). Credit: NASA Goddard Visualization Studio | + Enlarge image

Eclipses can occur when the Sun, the Moon and Earth align. Lunar eclipses can only happen during the full moon phase, when the Moon and the Sun are on opposite sides of Earth. At that point, the Moon could move into the shadow cast by Earth, resulting in a lunar eclipse. However, most of the time, the Moon’s slightly tilted orbit brings it above or below the shadow of Earth.

The time period when the Moon, Earth and the Sun are lined up and on the same plane – allowing for the Moon to pass through Earth’s shadow – is called an eclipse season. Eclipse seasons last about 34 days and occur just shy of every six months. When a full moon occurs during an eclipse season, the Moon travels through Earth’s shadow, creating a lunar eclipse.

Graphic showing the alignment of the Sun, Earth and Moon when a full moon occurs during an eclipse season versus a non-eclipse season

When a full moon occurs during an eclipse season, the Moon travels through Earth's shadow, creating a lunar eclipse. Credit: NASA/JPL-Caltech | + Enlarge image

Unlike solar eclipses, which require special glasses to view and can only be seen for a few short minutes in a very limited area, a total lunar eclipse can last over an hour and be seen by anyone on the nighttime side of Earth – as long as skies are clear!

Why It’s Important

Lunar eclipses have long played an important role in understanding Earth and its motions in space.

In ancient Greece, Aristotle noted that the shadows on the Moon during lunar eclipses were round, regardless of where an observer saw them. He realized that only if Earth were a spheroid would its shadows be round – a revelation that he and others had many centuries before the first ships sailed around the world.

Earth wobbles on its axis like a spinning top that’s about to fall over, a phenomenon called precession. Earth completes one wobble, or precession cycle, over the course of 26,000 years. Greek astronomer Hipparchus made this discovery by comparing the position of stars relative to the Sun during a lunar eclipse to those recorded hundreds of years earlier. A lunar eclipse allowed him to see the stars and know exactly where the Sun was for comparison – directly opposite the Moon. If Earth didn’t wobble, the stars would appear to be in the same place they were hundreds of years earlier. When Hipparchus saw that the stars’ positions had indeed moved, he knew that Earth must wobble on its axis!

Additionally, modern-day astronomers have used ancient eclipse records and compared them with computer simulations. These comparisons helped scientists determine the rate at which Earth’s rotation is slowing.

What to Expect

The Moon passes through two distinct parts of Earth’s shadow during a lunar eclipse. The outer part of the cone-shaped shadow is called the penumbra. The penumbra is less dark than the inner part of the shadow because it’s penetrated by some sunlight. (You have probably noticed that some shadows on the ground are darker than others, depending on how much outside light enters the shadow; the same is true for the outer part of Earth’s shadow). The inner part of the shadow, known as the umbra, is much darker because Earth blocks additional sunlight from entering the umbra.

Here's what to expect during the total lunar eclipse on Nov. 8, 2022, which will be visible in North and South America, as well as Asia and Australia. Viewers in the most eastern parts of the continental U.S. will see the Moon set below the horizon as it exits Earth’s shadow in the second half of the eclipse.

At 12:02 a.m. PST (3:02 a.m. EST), the edge of the Moon will begin entering the penumbra. The Moon will dim very slightly for the next 67 minutes as it moves deeper into the penumbra. Because this part of Earth’s shadow is not fully dark, you may only notice some dim shading (if anything at all) on the Moon near the end of this part of the eclipse. Should you decide to skip this part of the eclipse, you won’t miss much.

Graphic showing the positions of the Moon, Earth and Sun during a partial lunar eclipse

During a total lunar eclipse, the Moon first enters into the penumbra, or the outer part of Earth's shadow, where the shadow is still penetrated by some sunlight. Credit: NASA | + Enlarge image

At 1:09 a.m. PST (4:09 a.m. EST), the edge of the Moon will begin entering the umbra. As the Moon moves into the darker shadow, significant darkening will be noticeable. Some say that during this part of the eclipse, the Moon looks as if it has had a bite taken out of it. That “bite” gets bigger and bigger as the Moon moves deeper into the shadow.

The Moon as seen during a partial lunar eclipse

As the Moon starts to enter into the umbra, the inner and darker part of Earth's shadow, it appears as if a bite has been taken out of the Moon. This "bite" will grow until the Moon has entered fully into the umbra. Credit: NASA | + Enlarge image

At 2:16 a.m. PST (5:16 a.m. EST), the Moon will be completely inside the umbra, marking the beginning of the total lunar eclipse, also known as totality.

Graphic showing the Moon inside the umbra

The total lunar eclipse starts once the moon is completely inside the umbra. And the moment of greatest eclipse happens with the Moon is halfway through the umbra as shown in this graphic. Credit: NASA | + Enlarge image

The moment of greatest eclipse, when the Moon is halfway through its path across the umbra, occurs at 2:59 a.m. PST (5:59 a.m. EST). As the Moon moves completely into the umbra – the part of the eclipse known as totality – something interesting happens: The Moon begins to turn reddish-orange. The reason for this phenomenon? Earth’s atmosphere. As sunlight passes through it, the small molecules that make up our atmosphere scatter blue light, which is why the sky appears blue. This leaves behind mostly red light that bends, or refracts, into Earth’s shadow. We can see the red light during an eclipse as it falls onto the Moon in Earth’s shadow. This same effect is what gives sunrises and sunsets a reddish-orange color.

The Moon as seen during a total lunar eclipse at the point of greatest eclipse

As the Moon moves completely into the umbra, it turns a reddish-orange color. Credit: NASA | + Enlarge image

A variety of factors affect the appearance of the Moon during a total lunar eclipse. Clouds, dust, ash, photochemical droplets and organic material in the atmosphere can change how much light is refracted into the umbra. The potential for variation provides a great opportunity for students to observe and classify the lunar eclipse based on its brightness. Details can be found below in the Teach It section.

At 3:41 a.m. PST (6:41 a.m. EST), the edge of the Moon will begin exiting the umbra and moving into the opposite side of the penumbra, reversing the “bite” pattern seen earlier. At this point, the Moon will have just set in the most northeastern portions of the continental United States. More and more eastern states will see the Moon set over the next hour as the eclipse progresses.

At 4:49 a.m. PST, the Moon will be completely outside of the umbra and no longer visible in the eastern United States. Those in the central United States will see the Moon begin setting around this time (6:49 a.m. CST). The Moon will continue exiting the penumbra until the eclipse officially ends at 5:56 a.m. PST, remaining visible only to viewers in the western United States, including many in the Mountain Time Zone one hour ahead.

Teach It

Ask students to observe the lunar eclipse and evaluate the Moon’s brightness using the Danjon Scale of Lunar Eclipse Brightness. The Danjon scale illustrates the range of colors and brightness the Moon can take on during a total lunar eclipse and is a tool observers can use to characterize the appearance of an eclipse. View the lesson guide here. After the eclipse, have students compare and justify their evaluations of the eclipse.

Use these standards-aligned lessons and related activities to get your students excited about the eclipse, moon phases, and Moon observations.

Educator Guides & Resources

Student Activities

Explore More

TAGS: Lunar Eclipse, Moon, Super Blue Blood Moon, Observe the Moon, Eclipse, K-12, Classroom Activities, Teaching

  • Lyle Tavernier
READ MORE

Collage of James Webb Space Telescope's first images featured in this article.

Here's what we learned from the first set of images captured by NASA's newest space observatory and how to translate it into learning opportunities for students.


NASA’s newest space observatory, the James Webb Space Telescope, has returned its first set of images and spectra of five different targets – from nebulae to exoplanets to galaxy clusters – revealing the universe in ways never before seen. These targets, selected by a team of experts, represent just the start of the telescope's science operations and the beginning of our ability to see the universe in a whole new way.

Read on to learn more about what the space-based observatory’s images can tell us about the cosmos, how they were captured, and how to engage learners in the science and engineering behind the mission.

What JWST Saw

New Details Revealed About the Birth of Stars

Link to image text description in caption.

What looks much like craggy mountains on a moonlit evening is actually the edge of a nearby, young, star-forming region NGC 3324 in the Carina Nebula. Captured in infrared light by the Near-Infrared Camera (NIRCam) on NASA’s James Webb Space Telescope, this image reveals previously obscured areas of star birth. Credit: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

Stellar nurseries, young stars, and protostellar jets, which are narrow, ultra-fast streams of gas emanating from baby stars, are all on display in this image of the Carina Nebula, a cloud of gas and dust approximately 7,600 light years away.

Nebulae are massive clouds of gas and dust, some spanning up to hundreds of light-years across. Thanks to its infrared cameras, JWST can peer into these dusty regions of space, revealing incredible details previously unseen by other telescopes.

Within the Carina Nebula, a star-forming region known as NGC 3324 was captured by the Webb telescope in this image. As the edge of this region moves inward toward the gas and dust, it may encounter unstable areas. The pressure changes can cause the gas and dust to collapse, forming a new star in a process called accretion. However, if too much material is pushed away, it may prevent a star from forming.

The Webb telescope’s observations in nebulae like this will help scientists answer some of the unknown questions of astrophysics, like what determines the number of stars in a certain region and why do stars form with certain masses.

Scientists can also learn how star formation affects these clouds. Little is known about the numerous small, or low-mass, stars within nebulae. But by studying the jets revealed in the new image, scientists can understand how these stars are expelling gas and dust out of the cloud, thereby reducing the amount of material available to form new stars. Furthermore, scientists will be able to get a full count of these low-mass stars and account for their impact throughout the nebula.

Signs of Water on a Distant Planet

Link to image text description in caption.

A transmission spectrum made from a single observation using Webb’s Near-Infrared Imager and Slitless Spectrograph (NIRISS) reveals atmospheric characteristics of the hot gas giant exoplanet WASP-96 b. Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

JWST's observations of exoplanet WASP-96 b, a planet outside our solar system, is not an image but a spectrum of light. Within the spectrum are highlights that indicate the presence of water molecules. The spectrum also shows evidence of clouds and haze, which were thought not to exist in WASP-96 b's atmosphere.

WASP-96 b is an exoplanet made up mostly of gas. About half the mass of Jupiter, but slightly larger, it orbits much closer to its star, completing a revolution every 3.4 days compared with 12 years for Jupiter.

This measurement, known as a transmission spectrum, was collected as WASP-96 b transited, or passed in front of, its host star from the perspective of the telescope. It compares the light that passed through the atmosphere of the exoplanet with the light from the planet's parent star alone. As a result, it is possible to see the amount of light at each wavelength blocked by the planet and absorbed by its atmosphere, telling scientists the size of the planet and the chemicals contained in its atmosphere.

While WASP-96 b’s spectrum had been captured before, the Webb telescope provided the most detailed view of its spectrum in near-infrared, and the improved resolution completely changed our understanding of the exoplanet’s atmosphere. Using this spectrum, scientists will be able to measure the amount of water in the exoplanet's atmosphere, determine how much oxygen and carbon it contains, infer the make-up of the planet, and even how, when, and where it formed.

Star Pair Coming Into Focus

Link to image text description in caption.

NASA’s Webb Telescope has revealed the cloak of dust around the second star, shown at left in red, at the center of the Southern Ring Nebula for the first time. It is a hot, dense white dwarf star. Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

Two distinct stars can be seen in this image of the center of the Southern Ring Nebula – a pairing that was believed to exist but was not visible in previous images.

The star pair came into view thanks to the space telescope's MIRI instrument, which is designed to capture wavelengths of light in the mid-infrared range of the electromagnetic spectrum. MIRI’s ability to see in the mid-infrared revealed that the older of the two stars is surrounded by dust. Seeing this dust clearly is what makes the second star visible in the image. While the brighter star is in an earlier stage of its life, it will likely form its own planetary nebula in the future.

About 2,500 light-years away from Earth, the Southern Ring is a planetary nebula – a shell of gas and dust shed from a dying white dwarf star at its center. Its gases stretch out for nearly half a light-year and are speeding away from the star at approximately nine miles per second!

Link to image text description in caption.

The bright star at the center of NGC 3132, while prominent when viewed by NASA’s Webb Telescope in near-infrared light, plays a supporting role in sculpting the surrounding nebula. A second star, barely visible at lower left along one of the bright star’s diffraction spikes, is the nebula’s source. It has ejected at least eight layers of gas and dust over thousands of years. Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

The images from JWST reveal that starlight streams out of the nebula in fine lines, the result of holes in the surrounding gas and dust cloud. The types and locations of different molecules within the cloud, gleaned from the captured spectra, will help to fine tune our understanding of the structure, composition, and history of this nebula, and with future observations, other nebulae.

How Galaxies Interact

Link to image text description in caption.

An enormous mosaic of Stephan’s Quintet is the largest image to date from NASA’s James Webb Space Telescope, covering about one-fifth of the Moon’s diameter. It contains over 150 million pixels and is constructed from almost 1,000 separate image files. The visual grouping of five galaxies was captured by Webb’s Near-Infrared Camera (NIRCam) and Mid-Infrared Instrument (MIRI). Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

The Webb telescope's capabilities bring new eyes to a cluster of galaxies first discovered in 1877 and known as Stephan’s Quintet. On display in this sharp new image are regions of new star birth containing millions of young stars as well as tails of gas, dust, and stars being ripped from galaxies as a result of gravitational forces between the galaxies.

Stephan’s Quintet is a dense cluster of galaxies located 290 million light-years away in the constellation Pegasus. Four of the five galaxies within the quintet are locked in orbits that repeatedly bring them close to one another. The fifth (leftmost) galaxy is seven times closer to Earth than the others. But its location within the line of sight of the distant four makes it appear to be grouped with them. What looks like speckles surrounding the nearby galaxy and could be mistaken for digital noise is actually individual stars from that galaxy.

It may seem distant in pure numbers, but Stephan's Quintet is relatively close compared to galaxies that are billions of light-years away. Its proximity gives astronomers a great view of the interactions that occur between galaxies that are near to each other.

Link to image text description in caption.

The MIRI instrument measured the composition of gas around the black hole at the center of one of the galaxies in Stephan's Quintent to find a region filled with hot, ionized gases, including iron, argon, neon, sulfur and oxygen (top spectrum). The instrument also revealed that the supermassive black hole has a reservoir of colder, denser gas with large quantities of molecular hydrogen and silicate dust (bottom spectrum). Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

The detail exposed will allow scientists to understand the interactions occurring in much more distant – and harder to observe – galaxies. Close inspections of galactic nuclei captured in mid-infrared by the telescope's MIRI instrument revealed hot gas being stripped of its electrons by winds and radiation from a supermassive black hole at the center of one galaxy. The new detail helped scientists determine that iron, argon, neon, sulfur and oxygen, as well as silicate dust are contained in these gases.

Meanwhile, the telescope's NIRSpec instrument – which can capture up to 100 spectra at a time – was able to identify atomic and molecular hydrogen as well as iron ions in the gases around the black hole. These observations will provide a greater understanding about the rate at which supermassive black holes feed and grow.

Thousands of Galaxies in a Grain of Sand

Link to image text description in caption.

NASA’s James Webb Space Telescope has produced the deepest and sharpest infrared image of the distant universe to date. Known as Webb’s First Deep Field, this image of galaxy cluster SMACS 0723 is overflowing with detail. Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

This image contains thousands of galaxies as well as the faintest objects yet observed in the infrared. Known as a deep field image, it was made by pointing the telescope at the target for an extended period of time, allowing the detectors to collect as much of the faint, distant light as possible. JWST captured this deep field image in just 12.5 hours, while the Hubble Space Telescope spent two weeks capturing its deepest images. (Note that Hubble also observed this galaxy cluster, but not as a deep field image.)

Hold a single grain of sand at arm's length and you could cover the entire area of space captured by this image. Keen observers will notice what appear as warped or stretched galaxies. Those are the result of gravitational lensing, a phenomenon in which the gravity of the galaxy cluster centered in the foreground bends the light from background galaxies magnifying and distorting their light. Taking advantage of this phenomenon allows for viewing of extremely distant and very faint galaxies.

The galaxy cluster shown in the image is known as SMACS 0723 and it appears as it did 4.6 billion years ago – the length of time it took for its light to reach the telescope. Light from the oldest-known galaxy in the image had been traveling for 13.1 billion years before it reached JWST.

Link to image text description in caption.

Galaxy cluster SMACS 0723 is a technicolor landscape when viewed in mid-infrared light by NASA’s James Webb Space Telescope. Compared to Webb’s near-infrared image at right, the galaxies and stars are awash in new colors. Credits: NASA, ESA, CSA, STScI | › Full image and caption | › Text description (PDF)

The MIRI instrument’s ability to detect longer infrared wavelengths provides additional information in the image about the make-up of those galaxies. Mid-infrared light highlights dust, an important star-forming ingredient. In this image, red objects contain thick dust layers, while blue galaxies contain stars but not much dust. Green objects contain dust filled with hydrocarbons and other compounds. With these data, astronomers will be able to better understand the formation and growth of galaxies.

As impressive as this image is, the JWST team has plans to capture more deep field images using even longer exposure times. Keep up to date with the latest images and spectra from JWST throughout the school year at the Webb Space Telescope Resource Gallery.

How They Did It

The Webb telescope's ability to detect these objects in such great detail is enabled by its size, the way it observes the universe, and the unique technologies aboard. We went into more detail about how JWST works in a previous Teachable Moment, but below you’ll find a review of some of the important ways JWST was uniquely designed to capture these groundbreaking images.

Observing the Infrared

https://www.jpl.nasa.gov/edu/images/redshift_demo.gif

Light waves get stretched as the universe expands similar to how this ink mark stretches out as the elastic is pulled. Get students modeling and exploring this effect with this standards-aligned math lesson. Credit: NASA/JPL-Caltech | + Expand image

The Webb telescope was built with instruments like NIRSpec and MIRI that are sensitive to light in the near- and mid-infrared wavelengths to detect some of the most distant objects in space.

As light from distant objects travels to Earth, the universe expands, something it’s been doing since the Big Bang. The waves that make up the light get stretched as the universe expands. Visible lightwaves from distant objects that you would be able to see with your eyes get stretched out so far that the longer wavelengths shift from visible light into infrared. Scientists refer to this phenomenon as redshift – and the farther away an object is, the more redshift it undergoes.

Gathering Light

The light from some of these distant objects has traveled so far that it is incredibly dim. To see such dim light, the Webb telescope was built to be extremely sensitive. On the Webb telescope, 18 hexagonal mirrors combine to form a massive primary mirror that is 21 feet (6.5 meters) across – six times the surface area of Hubble.

A dozen or so engineers stand in a towering open room clad in white smocks covering their entire bodies. Above them, and taking up a third of the room's space, is the reflective gold honeycomb-shaped set of mirrors for JWST. The NASA Goddard Space Center logo is reflected in the mirror.

The complete optical telescope element on display inside a clean room at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in 2017. Credits: NASA/Desiree Stover | › Full image and caption

To detect faint infrared light, the instruments inside the telescope have to be kept very cold, otherwise those infrared signals could get lost in the heat of the telescope. The spacecraft’s orbit and tennis-court-size sunshield keep light and heat from the Sun, Earth, and Moon from warming up its sensitive instruments. And the MIRI instrument, which needs to be even colder to capture mid-infrared wavelengths, is equipped with a special cryocooler.

The unique design and innovative techniques used by the James Webb Space Telescope are what made the first images possible. As the mission continues, more targets will be observed, more discoveries will be made, and more of our universe will unfold before our eyes.

“It’s not every day you can say you contributed to something that inspires the world in a positive way, but I believe that’s what JWST is doing for everyone of all ages,” said JPL engineer Analyn Schneider, who is the project manager for the telescope's MIRI instrument. “The telescope will help us learn more about our galaxy and the rest of the universe, and as a bonus we get these magnificent images. Learning is a big part of being in science and engineering and that’s what makes it interesting and challenging.”

Teach It

Bring the excitement of these far-off observations closer to home by using the following resources in your learning environment, whether in-person, hybrid, or remote. Scientists and educators directly connected with the James Webb Space Telescope have teamed up to provide a collection of Webb resources to meet your needs. Find additional resources below and through NASA’s Universe of Learning project.

Lessons

Student Activities

Explore More



NASA's Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: Stars & Galaxies, JWST, K-12 Education, Teaching

  • Lyle Tavernier
READ MORE

A slightly oblong donut-shaped ring of glowing warm dust especially bright at spots on the top, left, and right surrounds a black hole.

Find out how scientists captured the first image of Sagittarius A*, why it's important, and how to turn it into a learning opportunity for students.


Our home galaxy, the Milky Way, has a supermassive black hole at its center, but we’ve never actually seen it – until now. The Event Horizon Telescope, funded by the National Science Foundation, has released the first image of our galactic black hole, Sagittarius A* (pronounced “Sagittarius A-star” and abbreviated Sgr A*).

Read on to find out how the image was acquired and learn more about black holes and Sagittarius A*. Then, explore resources to engage learners in the exciting topic of black holes.

How Black Holes Work

A black hole is a location in space with a gravitational pull so strong that nothing, not even light, can escape it. A black hole’s outer edge, called its event horizon, defines the spherical boundary where the velocity needed to escape exceeds the speed of light. Matter and radiation fall in, but they can’t get out. Because not even light can escape, a black hole is literally black. Contrary to their name’s implication, black holes are not empty. In fact, a black hole contains a great amount of matter packed into a relatively small space. Black holes come in various sizes and can exist throughout space.

We can surmise a lot about the origin of black holes from their size. Scientists know how some types of black holes form, yet the formation of others is a mystery. There are three different types of black holes, categorized by their size: stellar-mass, intermediate-mass, and supermassive black holes.

Stellar-mass black holes are found throughout our Milky Way galaxy and have masses less than about 100 times that of our Sun. They comprise one of the possible endpoints of the lives of high-mass stars. Stars are fueled by the nuclear fusion of hydrogen, which forms helium and other elements deep in their interiors. The outflow of energy from the central regions of the star provides the pressure necessary to keep the star from collapsing under its own weight.

A bubble if gas is sucked into a swirl of glowing dust and gas around a black hole as hair-like whisps extend from the top and bottom of the swirl.

This illustration shows a binary system containing a stellar-mass black hole called IGR J17091-3624. The strong gravity of the black hole, on the left, is pulling gas away from a companion star on the right. This gas forms a disk of hot gas around the black hole, and the wind is driven off this disk. Image credit: NASA/CXC/M.Weiss | › Full image and caption

Once the fuel in the core of a high-mass star has completely burned out, the star collapses, sometimes producing a supernova explosion that releases an enormous amount of energy, detectable across the electromagnetic spectrum. If the star’s mass is more than about 25 times that of our Sun, a stellar-mass black hole can form.

Intermediate-mass black holes have masses between about 100 and 100,000 times that of our Sun. Until recently, the existence of intermediate-mass black holes had only been theorized. NASA’s Chandra X-ray Observatory has identified several intermediate-mass black hole candidates by observing X-rays emitted by the gas surrounding the black hole. The Laser Interferometer Gravitational Wave Observatory, or LIGO, funded by the National Science Foundation, detected the merger of two stellar-mass black holes with masses 65 and 85 times that of our Sun forming an intermediate-mass black hole of 142 solar masses. (Some of the mass was converted to energy and about nine solar masses were radiated away as gravitational waves.)

Supermassive black holes contain between a million and a billion times as much mass as a stellar-mass black hole. Scientists are uncertain how supermassive black holes form, but one theory is that they result from the combining of stellar-mass black holes.

A scale on the bottom shows mass (relative to the Sun) from 1 to 1 million and beyond. Stellar-mass black holes are shown on the left side of the scale between about 10 and 100 solar masses, followed on the right by intermediate-mass black holes from 100 to over 100,000 stellar masses followed by supermassive black holes from about 1 million on.

This chart illustrates the relative masses of super-dense cosmic objects, ranging from white dwarfs to the supermassive black holes encased in the cores of most galaxies. | › Full image and caption

Our local galactic center’s black hole, Sagittarius A*, is a supermassive black hole with a mass of about four million suns, which is fairly small for a supermassive black hole. NASA’s Hubble Space Telescope and other telescopes have determined that many galaxies have supermassive black holes at their center.

A bright-white collection of stars is surrounded by a berry colored swirl of stellar dust and stars.

This image shows the center of the Milky Way galaxy along with a closer view of Sagittarius A*. It was made by combining X-ray images from NASA's Chandra X-ray Observatory (blue) and infrared images from the agency's Hubble Space Telescope (red and yellow). The inset shows Sgr A* in X-rays only, covering a region half a light year wide. Image credit: X-ray: NASA/UMass/D.Wang et al., IR: NASA/STScI | › Full image and caption

Why They're Important

Black holes hold allure for everyone from young children to professional astronomers. For astronomers, in particular, learning about Sagittarius A* is important because it provides insights into the formation of our galaxy and black holes themselves.

Understanding the physics of black hole formation and growth, as well as their surrounding environments, gives us a window into the evolution of galaxies. Though Sagittarius A* is more than 26,000 light years (152 quadrillion miles) away from Earth, it is our closest supermassive black hole. Its formation and physical processes influence our galaxy as galactic matter continually crosses the event horizon, growing the black hole’s mass.

Studying black holes also helps us further understand how space and time interact. As one gets closer to a black hole, the flow of time slows down compared with the flow of time far from the black hole. In fact, according to Einstein’s theory of general relativity, the flow of time slows near any massive object. But it takes an incredibly massive object, such as a black hole, to make an appreciable difference in the flow of time. There's still much to learn about what happens to time and space inside a black hole, so the more we study them, the more we can learn.

How Scientists Imaged Sagittarius A*

Black holes, though invisible to the human eye, can be detected by observing their effects on nearby space and matter. As a result of their enormous mass, black holes have extremely high gravity, which pulls in surrounding material at rapid speeds, causing this material to become very hot and emit X-rays.

This video explains how Sagittarius A* appears to still have the remnants of a blowtorch-like jet dating back several thousand years. Credit: NASA | Watch on YouTube

X-ray-detecting telescopes such as NASA’s Chandra X-ray Observatory can image the material spiraling into a black hole, revealing the black hole’s location. NASA’s Hubble Space Telescope can measure the speed of the gas and stars orbiting a point in space that may be a black hole. Scientists use these measurements of speed to determine the mass of the black hole. Hubble and Chandra are also able to image the effects of gravitational lensing, or the bending of light that results from the gravitational pull of black holes or other high-mass objects such as galaxies.

A bright central blob is surrounded by blue halos and whisps forming a sort of target pattern.

The thin blue bull's-eye patterns in this Hubble Space Telescope image are called "Einstein rings." The blobs are giant elliptical galaxies roughly 2 to 4 billion light-years away. And the bull's-eye patterns are created as the light from galaxies twice as far away is distorted into circular shapes by the gravity of the giant elliptical galaxies. | › Full image and caption

To directly image the matter surrounding a black hole, thus revealing the silhouette of the black hole itself, scientists from around the world collaborated to create the Event Horizon Telescope. The Event Horizon Telescope harnesses the combined power of numerous telescopes around the world that can detect radio-wave emissions from the sky to create a virtual telescope the size of Earth.

Narrated by Caltech’s Katie Bouman, this video explains how she and her fellow teammates at the Event Horizon Telescope project managed to take a picture of Sagittarius A* (Sgr A*), a beastly black hole lying 27,000 light-years away at the heart of our Milky Way galaxy. Credit: Caltech | Watch on YouTube

In 2019, the team released the first image of a black hole's silhouette when they captured the glowing gasses surrounding the M87* galactic black hole nearly 53 million light-years (318 quintillion miles) away from Earth. The team then announced that one of their next endeavors was to image Sagittarius A*.

A warm glowing ring surrounds an empty blackness.

Captured by the Event Horizon Telescope in 2019, this image of the the glowing gasses surrounding the M87* black hole, was the first image ever captured of a black hole. Image credit: Event Horizon Telescope Collaboration | + Expand image

To make the newest observation, the Event Horizon Telescope focused its array of observing platforms on the center of the Milky Way. A telescope array is a group of telescopes arranged so that, as a set, they function similarly to one giant telescope. In addition to the telescopes used to acquire the M87* image, three additional radio telescopes joined the array to acquire the image of Sagittarius A*: the Greenland Telescope, the Kitt Peak 12-meter Telescope in Arizona, and the NOrthern Extended Millimeter Array, or NOEMA, in France.

This image of the center of our Milky Way galaxy representing an area roughly 400 light years across, has been translated into sound. Listen for the different instruments representing the data captured by the Chandra X-ray Observatory, Hubble Space Telescope, and Spitzer Space Telescope. The Hubble data outline energetic regions where stars are being born, while Spitzer's data captures glowing clouds of dust containing complex structures. X-rays from Chandra reveal gas heated to millions of degrees from stellar explosions and outflows from Sagittarius A*. Credit: Chandra X-ray Observatory | Watch on YouTube

The distance from the center of Sagittarius A* to its event horizon, a measurement known as the Schwarzschild radius, is enormous at seven million miles (12,000,000 kilometers or 0.08 astronomical units). But its apparent size when viewed from Earth is tiny because it is so far away. The apparent Schwarzschild radius for Sagittarius A* is 10 microarcseconds, about the angular size of a large blueberry on the Moon.

Acquiring a good image of a large object that appears tiny when viewed from Earth requires a telescope with extraordinarily fine resolution, or the ability to detect the smallest possible details in an image. The better the resolution, the better the image and the more detail the image will show. Even the best individual telescopes or array of telescopes at one location do not have a good enough resolution to image Sagittarius A*.

A dense field of stars like grains of sand is surrounded by wispy clouds of glowing gas and dust.

This image captured by NASA's Hubble Space Telescope shows the star-studded center of the Milky Way towards the constellation of Sagittarius. Even though you can't see our galaxy's central black hole directly, you might be able to pinpoint its location based on what you've learned about black holes thusfar. Image credit: NASA, ESA, and G. Brammer | › Full image and caption

The addition of the 12-meter Greenland Telescope, though a relatively small instrument, widened the diameter, or aperture, of the Event Horizon Telescope to nearly the diameter of Earth. And NOEMA – itself an array of twelve 15-meter antennas with maximum separation of 2,500 feet (760 meters) – helped further increase the Event Horizon Telescope’s light-gathering capacity.

Altogether, when combined into the mighty Event Horizon Telescope, the virtual array obtained an image of Sagittarius A* spanning about 50 microarcseconds, or about 1/13th of a billionth the span of the night sky.

A slightly oblong donut-shaped ring of glowing warm dust especially bright at spots on the top, left, and right surrounds a black hole.

Sagittarius A* is more than 26,000 light years (152 quadrillion miles) away from Earth and has the mass of 4 million suns. Image credit: Event Horizon Telescope | › Full image and caption

While the Event Horizon Telescope was busy capturing the stunning radio image of Sagittarius A*, an additional worldwide contingent of astronomical observatories was also focused on the black hole and the region surrounding it. The aim of the team, known as the Event Horizon Telescope Multiwavelength Science Working Group, was to observe the black hole in other parts of the electromagnetic spectrum beyond radio. As part of the effort, X-ray data were collected by NASA’s Chandra X-ray Observatory, Nuclear Spectroscopic Telescope (NuSTAR), and Neil Gehrels Swift Observatory, additional radio data were collected by the East Asian Very Long-Baseline Interferometer (VLBI) network and the Global 3 millimeter VLBI array, and infrared data were collected by the European Southern Observatory’s Very Large Telescope.

The data from these multiple platforms will allow scientists to continue building their understanding of the behavior of Sagittarius A* and to refine their models of black holes in general. The data collected from these multiwavelength observations are crucial to the study of black holes, such as the Chandra data revealing how quickly material falls in toward the disk of hot gas orbiting the black hole’s event horizon. Data such as these will hopefully help scientists better understand black hole accretion, or the process by which black holes grow.

Teach It

Check out these resources to bring the real-life STEM of black holes into your teaching, plus learn about opportunities to involve students in real astronomy research.

Explore More

Articles

Educator Guides

Student Activities

Check out these related resources for students from NASA’s Space Place

Across the NASA-Verse


This Teachable Moment was created in partnership with NASA’s Universe of Learning. Universe of Learning materials are based upon work supported by NASA under award number NNX16AC65A to the Space Telescope Science Institute, working in partnership with Caltech/IPAC, Center for Astrophysics | Harvard & Smithsonian, and the Jet Propulsion Laboratory.

TAGS: Black hole, Milky Way, galaxy, universe, stars, teachers, educators, lessons, Teachable Moments, K-12, science

  • Ota Lutz
READ MORE

A small piece of the ISS is visible in the top corner of this view looking down from space station over Earth. A large cloud of dust takes half the view over Earth's surface.

A data map overlaid on the globe shows thick swirls of dust traveling from West Africa, across the Atlantic Ocean and all the way to the Caribbean and Southern U.S.

Learn about the role that dust plays in Earth's climate, why scientists are interested in studying dust from space, and how to engage students in the science with STEM resources from JPL.


A NASA instrument launched to the International Space Station this summer will explore how dust impacts global temperatures, cloud formation, and the health of our oceans. The Earth Surface Mineral Dust Source Investigation, or EMIT, is the first instrument of its kind, designed to collect measurements from space of some of the most arid regions on Earth to understand the composition of soils that generate dust and the larger role dust plays in climate change.

Read on to find out how the instrument works and why scientists are hoping to learn more about the composition of dust. Then, explore how to bring the science into your classroom with related climate lessons that bridge physical sciences with engineering practices.

Why It’s Important

Scientists have long studied the movements of dust. The fact that dust storms can carry tiny particles great distances was reported in the scientific literature nearly two centuries ago by none other than Charles Darwin as he sailed across the Atlantic on the HMS Beagle. What still remains a mystery all these years later is what that dust is made of, how it moves, and how that affects the health of our planet.

For example, we now know that dust deposited on snow speeds up snow melt even more than increased air temperature. That is to say, that dust traveling to cold places can cause increased snow melt.

Sharp mountain peaks are covered in splotches of snow with a fine coating of dust visible on top of the snow.

A coating of dust on snow speeds the pace of snowmelt in the spring. Credit: NASA | + Expand image

Dust can affect air temperatures as well. For example, dust with more iron absorbs light and can cause the air to warm, while dust with less iron reflects light and is responsible for local cooling. Iron in dust can also act as a fertilizer for plankton in oceans, supplying them with nutrients needed for growth and reproduction.

A plume of dust eminates from over the Copper River in Alaska, spreading out as this series of overhead satellite images progresses.

A plume of dust is shown emanating from over Alaska's Copper River in October 2016 in these images captured by the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument on NASA’s Terra and Aqua satellites. Dust storms play a key role in fueling phytoplankton blooms by delivering iron to the Gulf of Alaska. Credit: NASA | › Full image and caption

Floating dust potentially alters the composition of clouds and how quickly or slowly they form, which can ultimately impact weather patterns, including the formation of hurricanes. That’s because clouds need particles to act as seeds around which droplets of moisture in the atmosphere can form. This process of coalescing water particles, called nucleation, is one factor in how clouds form.

An overhead view of a swirl of clouds mixed with a streak of dust like a swirl of milk froth in a cappuccino

A swirl of dust mixes with the clouds in a low-pressure storm over the Gobi desert between Mongolia and China. This image was captured by the MODIS instrument on the Terra satellite in May 2019. Credit: NASA | › Full image and caption

Thanks to EMIT, we’ll take the first steps in understanding how the movements of dust particles contribute to local and global changes in climate by producing “mineral maps”. These mineral maps will reveal differences in the chemical makeup of dust, providing essential information to help us model the way dust can transform Earth’s climate.

› Learn more about what EMIT will do from JPL News

How It Works

NASA has been exploring how dust moves across the globe by combining on-the-ground field studies with cutting-edge technology.

Dr. Olga Kalashnikova, an aerosol scientist at NASA's Jet Propulsion Laboratory and a co-investigator for EMIT, has been using satellite data to study atmospheric mineral dust for many years, including tracking the movements of dust and investigating trends in the frequency of dust storms.

As Dr. Kalashnikova describes, “From the ground, we can see what types of dusts are lifted into the atmosphere by dust storms on a local scale, but with EMIT, we can understand how they differ and where they originally came from.”

EMIT is the first instrument designed to observe a key part of the mineral dust cycle from space, allowing scientists to track different dust compositions on a global scale, instead of in just one region at a time. To understand dust’s impact on Earth’s climate, scientists will use EMIT to answer key questions, including:

  • How does dust uplifted in the atmosphere alter global temperatures?
  • What role do dusts play in fertilizing our oceans when they are deposited?
  • How do dust particles in the atmosphere affect cloud nucleation; the process by which clouds are ‘seeded’ and begin to coalesce into larger clouds?
A picture of the EMIT instrument, shaped like a small megaphone, is overlaid on an picture of the International Space Station flying above Earth.

The EMIT instrument will fly aboard the International Space Station, which orbits Earth about once every 90 minutes, completing about 16 orbits per day. Credit: NASA | + Expand image

To achieve its objectives, EMIT will spend 12 months collecting what are called “hyperspectral images” of some of the most arid regions of our planet selected by scientists and engineers as areas of high dust mobility, such as Northern Africa, the Middle East, and the American Southwest.

These images are measurements of light reflected from the Earth below, calibrated to the distinct patterns, or spectra, of light we see when certain minerals are present. The EMIT team has identified 10 minerals that are most common, including gypsum, hematite, and kaolinite.

Bands of satellite images looking at a seciton of Earth are highlighted in different colors to reveal different concentrations of minerals.

This example spectra shows how scientists will be able to identify different concentrations of minerals and elements in data collected by EMIT. Credit: NASA/JPL-Caltech | + Expand image

Why are these minerals important? One key reason is the presence or absence of the element iron, found in some minerals but not others.

Dr. Bethany Ehlmann is a planetary scientist and co-investigator for the EMIT project at Caltech and explains that when it comes to heating, “a little bit of iron goes a long way.” Iron in minerals absorbs visible and infrared light, meaning that even if only a small amount is present, it will result in a much warmer dust particle. Large amounts of warm dust in our atmosphere may have an impact on temperatures globally since those dust particles radiate heat as they travel, sometimes as far as across oceans!

Collecting images from space is, of course, no easy task, especially when trying to look only at the ground below. Yet it does allow scientists to get a global picture that's not possible to capture from the ground. Field studies allow us to take individual samples from tiny places of interest, but from space, we can scan the entire planet in remote places where no scientist can visit.

Of course, there are some complications in trying to study the light reflected off the surface of Earth, such as interference from clouds. To prevent this problem, the EMIT team plans to collect data at each location several times to ensure that the images aren’t being obscured by clouds between the instrument and the minerals we’re looking for.

The data collected by EMIT will provide a map of the compositions of dust from dry, desert environments all over the world, but the team involved won’t stop there. Knowing more about what the dust is made of sets the stage for a broader understanding of a few more of the complex processes that make up our global climate cycle. Upon completion of this study, EMIT's mineral maps will support further campaigns to complete our global dust picture. For example, NASA hopes to couple the data from EMIT with targeted field campaigns, in which scientists can collect wind-blown dust from the ground to learn more about where dust particles move over time and answer questions about what types of dust are on the go.

Furthermore, missions such as the Multiangle Imager for Aerosols, or MAIA, will allow us to better understand the effects of these dust particles on air-quality and public health.

Teach it

Studying Earth’s climate is a complex puzzle, consisting of many trackable features. These can range from sea level to particles in our atmosphere, but each makes a contribution to measuring the health of our planet. Bring EMIT and NASA Earth Science into your classroom with these lessons, articles, and activities to better understand how we’re exploring climate change.

Educator Guides

Student Activities

Articles

Websites

TAGS: Earth, climate, geology, weather, EMIT, Teachers, Classroom, Lessons, Earth Science, Climate Change, Dust, Global Warming, Educators, K-12, Teachable Moments, Climate TM

  • Brandon Rodriguez
READ MORE

The Millennium Falcon takes on TIE fighters in a scene from 'Star Wars: The Force Awakens.'

Science fiction meets science fact in this Star Wars inspired Teachable Moment all about ion propulsion and Newton’s Laws.

In the News

What do "Star Wars," NASA's Dawn spacecraft and Newton's Laws of Motion have in common? An educational lesson that turns science fiction into science fact using spreadsheets – a powerful tool for developing the scientific models addressed in the Next Generation Science Standards. Keep reading to learn more and find out how to get students wielding the force.

Why It's Important

The TIE (Twin Ion Engine) fighter is a staple of the "Star Wars" universe. Darth Vader flew one in "A New Hope." Poe Dameron piloted one in "The Force Awakens." And many, many Imperial pilots met their fates in them. While the fictional TIE fighters in "Star Wars" flew a long time ago in a galaxy far, far away, ion engines are a reality in this galaxy today – and have a unique connection to NASA’s Jet Propulsion Laboratory.

Launched in 1998, the first spacecraft to use an ion engine was Deep Space 1, which flew by asteroid 9969 Braille and comet Borrelly. Fueled by the success of Deep Space 1, engineers at JPL set forth to develop the next spacecraft that would use ion propulsion. This mission, called Dawn, would take ion-powered spacecraft to the next level by allowing Dawn to go into orbit twice – around the two largest objects in the asteroid belt: Vesta and Ceres.

How It Works

Ion engines rely on two principles that Isaac Newton first described in 1687. First, a positively charged atom (ion) is pushed out of the engine at a high velocity. Newton’s Third Law of Motion states that for every action there is an equal and opposite reaction, so then a small force pushes back on the spacecraft in the opposite direction – forward! According to Newton’s Second Law of Motion, there is a relationship between the force (F) exerted on an object, its mass (m) and its acceleration (a). The equation F=ma describes that relationship and tells us that the small force applied to the spacecraft by the exiting atom provides a small amount of acceleration to the spacecraft. Push enough atoms out, and you'll get enough acceleration to really speed things up.


Why is It Important?

Compared with traditional chemical rockets, ion propulsion is faster, cheaper and safer:

  • Faster: Spacecraft powered by ion engines can reach speeds of up to 90,000 meters per second (more than 201,000 mph!)
  • Cheaper: When it comes to fuel efficiency, ion engines can reach more than 90 percent fuel efficiency, while chemical rockets are only about 35 percent efficient.
  • Safer: Ion thrusters are fueled by inert gases. Most of them use xenon, which is a non-toxic, chemically inert (no risk of exploding), odorless, tasteless and colorless gas.

These properties make ion propulsion a very attractive solution when engineers are designing spacecraft. While not every spacecraft can use ion propulsion – some need greater rates of acceleration than ion propulsion can provide – the number and types of missions using these efficient engines is growing. In addition to being used on the Dawn spacecraft and communication satellites orbiting Earth, ion propulsion could be used to boost the International Space Station into higher orbits and will likely be a part of many future missions exploring our own solar system.

Teach It

Newton’s Laws of Motion are an important part of middle and high school physical science and are addressed specifically by the Next Generation Science Standards as well as Common Core Math standards. The lesson "Ion Propulsion: Using Spreadsheets to Model Additive Velocity" lets students study the relationship between force, mass and acceleration as described by Newton's Second Law as they develop spreadsheet models that apply those principles to real-world situations.

Educator Guides

Student Activities

Explore More


This feature was originally published on May 3, 2016.

TAGS: May the Fourth, Star Wars Day, F=ma, ion propulsion, Dawn, Deep Space 1, lesson, classroom activity, NGSS, Common Core Math

  • Lyle Tavernier
READ MORE