The partial eclipse looks as if a bite has been taken out of the Sun. The annular looks like an orange ring around the blackened Moon. The total looks like wisps of white around the blackened Moon.

Get ready for the April 2024 total solar eclipse. Learn about the science behind solar eclipses, how to watch safely, and how to engage students in NASA science.


On April 8, 2024, a total solar eclipse will be visible across much of the central and northeastern United States, as well as parts of Mexico and Canada.

Whether you are traveling to the path of the total eclipse or will be able to step outside and watch the eclipse where you live, here's everything you need to know, including what to expect, how to watch safely, and how to engage in scientific observations and discovery with NASA.

What Are Solar Eclipses?

Solar eclipses occur when the Sun, the Moon, and Earth align. For this alignment to happen, two things need to be true. First, the Moon needs to be in the new moon phase, which is when the Moon’s orbit brings it between Earth and the Sun. Second, eclipses can only happen during eclipse seasons, which last about 34 days and occur just shy of every six months. An eclipse season is the time period when the Sun, the Moon, and Earth can line up on the same plane as Earth's orbit during a new or full moon. If a new moon happens during an eclipse season, the shadow cast by the Moon will land on Earth, resulting in a solar eclipse. Most of the time, because the Moon’s orbit is slightly tilted, the Moon’s shadow falls above or below Earth, and we don't get a solar eclipse.

Not all solar eclipses look the same. The distance between the Sun, the Moon, and Earth plays an important role in what we see during a solar eclipse. Even though the Moon is much smaller than the Sun (about 400 times smaller in diameter), the Sun and Moon look about the same size from Earth. This is because the Sun is about 400 times farther away than the Moon. But as the Moon travels its elliptical orbit around Earth, its size appears slightly larger when it is closer to Earth and slightly smaller when it is farther from Earth. This contributes to the different kinds of solar eclipses you might have heard about. For example:

  • During a total solar eclipse, the Moon is closer to Earth in its orbit and appears larger, completely blocking the Sun's disk. This allows viewers in the path of totality to see the Sun’s corona, which is usually obscured by the bright light of the Sun’s surface.
  • Whisps of white haze flare out around the blackened disk of the Moon, which completely covers the Sun's disk

    This image of a total solar eclipse was captured on Aug. 21, 2017 from Madras, Oregon. Image credit: NASA/Aubrey Gemignani | › Full image and caption

  • An annular solar eclipse occurs when the Sun, Moon, and Earth are properly aligned, but the Moon is farther away in its orbit, so it does not completely cover the Sun's disk from our perspective. Annular eclipses are notable for the "ring of fire," a thin ring of the Sun’s disk that's still visible around the Moon during annularity. The name annular eclipse comes from the world of mathematics, where a ring shape is known as an annulus.
  • The bubbling surface of the Sun's disk and the surrounding haze of orange and yellow light can be seen as a ring around the blackened disk of the Moon.

    On Jan. 4, 2017, the Hinode satellite captured these breathtaking images of an annular solar eclipse. Image credit: Hinode/XRT | › Full image and caption

  • Partial eclipses can happen for two reasons. First, viewers outside the path of totality during a total solar eclipse – or the path of annularity during an annular eclipse – will see only part of the Sun’s surface covered by the Moon. The other time a partial eclipse can occur is when the Moon is nearly above or below Earth in its orbit so only part of the Moon’s shadow falls on Earth. In this case, only part of the Sun’s surface will appear covered by the Moon.
  • The Sun appears to have a small bite taken out of the top of its yellow-orange disk. The bite grows in size in this sequence of three images.

    The Sun appears partially eclipsed in this series of photos taken from NASA’s Johnson Space Center in Houston on Aug. 21, 2017. Image credit: NASA/Noah Moran | › Full image and caption

How to Watch the Upcoming Solar Eclipse

First, an important safety note: Do not look directly at the Sun or view any part of the partial solar eclipse without certified eclipse glasses or a solar filter. Read more below about when you can safely view the total solar eclipse without eclipse glasses or a solar filter. Visit the NASA Eclipse website for more information on safe eclipse viewing.

When following proper safety guidelines, witnessing an eclipse is an unparalleled experience. Many “eclipse chasers” have been known to travel the world to see solar eclipses. Here's what to expect on April 8, 2024:

Map of where the October 14 annular eclipse will be visible. Refer to caption for list of locations.

The April 8 total solar eclipse will be visible across much of the central and northeastern United States, as well as Mexico and Canada. Meanwhile, viewers in all of the continental United States, Hawaii, Mexico, Central America, Greenland, Iceland, Ireland, Cook Islands, French Polynesia, the Azores, and parts of Alaska and the United Kingdom will be able to see a partial eclipse. (Note that in some areas, the eclipse will begin before sunrise or end after sunset). | › Full image and caption

The start time and visibility of the eclipse will depend on your location. You can use this map to find detailed eclipse information, including the start time, by clicking on your location.

The eclipse begins when the edge of the Moon first crosses in front of the disk of the Sun. This is called a partial eclipse and might look as if a bite has been taken out of the Sun.

It is important to keep your eclipse glasses on during all parts of the partial solar eclipse. The visible part of the Sun is tens of thousands of times brighter than what you see during totality. You can also use a pinhole camera to view the eclipse.

An approximately 115-mile-wide strip known as the path of totality is where the shadow of the Moon, or umbra, will fall on Earth. Inside this path, totality will be visible starting about 65 to 75 minutes after the eclipse begins.

If you are in the path of totality, it is safe to take off your eclipse glasses and look at the total eclipse only during totality. Be sure to put your glasses back on before the total phase ends and the surface of the Sun becomes visible again. Your viewing location during the eclipse will determine how long you can see the eclipse in totality. In the U.S., viewers can expect to see 3.5 to 5.5 minutes of totality.

After totality ends, a partial eclipse will continue for 60 to 80 minutes, ending when the edge of the Moon moves off of the disk of the Sun.

For more information about the start of the partial eclipse, the start and duration of totality, and the percentage of the Sun eclipsed outside the path of totality, find your location on this eclipse map.

On April 8, NASA Television will host a live broadcast featuring views from telescopes along the path of totality.

What Solar Eclipses Mean for Science

Solar eclipses provide a unique opportunity for scientists to study the Sun and Earth from land, air, and space, plus allow the public to engage in citizen science!

A solid red circle with a smaller white-outlined circle inside it is centered over the disk of the Sun. Streams of yellow, red, and orange shoot out from the Sun, all around the solid circle, while a large solar flare bursts out of the upper left portion of the circle. A time stamp in the corner reads 2000/02/27.

NASA’s Solar and Heliospheric Observatory, or SOHO, constantly observes the outer regions of the Sun’s corona using a coronagraph. Image credit: ESA/NASA/SOHO | + Expand image

Scientists measure incoming solar radiation, also known as insolation, to better understand Earth’s radiation budget – the energy emitted, reflected, and absorbed by our planet. Just as clouds block sunlight and reduce insolation, eclipses create a similar phenomenon, providing a great opportunity to study how increased cloud cover can impact weather and climate.

Solar eclipses can also help scientists study solar radiation in general and the structure of the Sun. On a typical day, the bright surface of the Sun, called the photosphere, is the only part of the Sun we can see. During a total solar eclipse, the photosphere is completely blocked by the Moon, leaving the outer atmosphere of the Sun (corona) and the thin lower atmosphere (chromosphere) visible. Studying these regions of the Sun’s atmosphere can help scientists understand solar radiation, why the corona is hotter than the photosphere, and the process by which the Sun sends a steady stream of material and radiation into space. Annular solar eclipses provide opportunities for scientists to practice their observation methods so that they'll be ready when a total solar eclipse comes around.

Citizen scientists can get involved in collecting data and participating in the scientific process during the eclipse through NASA’s GLOBE program. Anyone in the path of the eclipse and in partial eclipse areas can act as citizen scientists by measuring temperature and cloud cover data and report it using the GLOBE Observer app to help further the study of how eclipses affect Earth’s atmosphere.

Visit NASA's Eclipse Science page to learn more about the many ways scientists are using the eclipse to improve their understanding of Earth, the Moon, and the Sun.

Taking Eclipse Science Farther

Eclipses also make a great jumping-off point to concepts and techniques used in astrophysics and our search for planets beyond our solar system.

Similar to a solar eclipse, a transit occurs when a planet crosses in front of the face of a star. From Earth, the planets Venus and Mercury can occasionally be seen transiting in front of the Sun, appearing as small, dark dots. Transits are also useful for detecting exoplanets – distant planets around other stars. When an exoplanet passes in between its star and Earth, we can measure tiny dips in the star's brightness that tell scientists a planet is there even when it’s too small to see.

Another way that eclipse concepts are used for astrophysics is with coronagraphs, mechanisms inside telescopes that block the light from a star. By creating a sort of artificial eclipse, coronagraphs help scientists search for exoplanets by making much dimmer planets orbiting a star easier to see. For example, NASA’s Nancy Grace Roman Telescope, slated for launch later this decade, will use an advanced coronagraph to analyze and directly image planets that orbit other stars. Learn more about the astrophysics involved in eclipses, including the use of gravitational lensing to study background objects, from NASA’s Universe of Learning.

Learn how the coronagraph instrument on the Nancy Grace Roman Telescope will allow the spacecraft to peer at the universe through some of the most sophisticated sunglasses ever designed. | Watch on YouTube

Solar Eclipse Lessons and Projects

Use these standards-aligned lessons, plus related activities and resources, to get your students excited about the eclipse and the science that will be conducted during the eclipse.

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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: Solar Eclipse, Eclipse, Annular Eclipse, K-12 Education, Lessons, Classroom Resources, STEM Resources

  • Lyle Tavernier
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Icons and overlays showing an orbital path, heat map, and cat's heart rate are show over an image of an orange tabby cat laying on a gray couch and looking intently off to the side.

Find out how the now famous video beamed from space, showing a cat chasing a laser, marked a milestone for space exploration, and find resources to engage students in related STEM learning.


You may have seen in the news last month that NASA beamed a cat video from space. It was all part of a test of new technology known as Deep Space Optical Communications. While the video went down in cat video history, the NASA technology used to transmit the first ultra-high-definition video from deep space also represented a historic advancement for space exploration – the potential to stream videos from the Moon, Mars, and beyond.

Read on to learn how this new technology will revolutionize space communications. Then, explore STEM learning resources that will get students using coding, math, and engineering to explore more about how NASA communicates with spacecraft.

Why did NASA beam a cat video from space?

Communicating with spacecraft across the solar system means sending data – such as commands, images, measurements, and status reports – over enormous distances, with travel times limited by the speed of light. NASA spacecraft have traditionally used radio signals to transmit information to Earth via the Deep Space Network, or DSN. The DSN is made up of an array of giant antennas situated around the globe (in California, Spain, and Australia) that allow us to keep in contact with distant spacecraft as Earth rotates.

When scientists and engineers want to send commands to a spacecraft in deep space, they turn to the Deep Space Network, NASA’s international array of giant antennas. | Watch on YouTube

Although sending transmissions using radio frequencies works well, advances in spacecraft technology mean we're collecting and transmitting a lot more data than in the past. The more data a spacecraft collects and needs to transmit to Earth, the more time it takes to transmit that data. And with so many spacecraft waiting to take their turn transmitting via the DSN's antennas, a sort of data traffic jam is on the horizon.

This interactive shows a real-time simulated view of communications between spacecraft and the DSN. Explore more on DSN Now

To alleviate the potential traffic jam, NASA is testing technology known as optical communications, which allows spacecraft to send and receive data at a higher information rate so that each transmission takes less of the DSN’s time.

The technology benefits scientists and engineers – or anyone who is fascinated by space – by allowing robotic spacecraft exploring planets we can't yet visit in person to send high-definition imagery and stream video to Earth for further study. Optical communications could also play an important role in upcoming human missions to the Moon and eventually to Mars, which will require a lot of data transmission, including video communication.

But why transmit a video of a cat? For a test of this kind, engineers would normally send randomly generated test data. But, in this case, to mark what was a significant event for the project, the team at NASA's Jet Propulsion Laboratory worked with the center's DesignLab to create a fun video featuring the pet of a JPL employee – a now famous orange tabby named Taters – chasing a laser. The video was also a nod to the project's use of lasers (more on that in a minute) and the first television test broadcast in 1928 that featured a statue of the cartoon character Felix the Cat.

This 15-second ultra-high-definition video featuring a cat named Taters was streamed via laser from deep space by NASA on Dec. 11, 2023. | Watch on YouTube

How lasers improve spacecraft communications

The NASA project designed to test this new technology is known as Deep Space Optical Communications, or DSOC. It aims to prove that we can indeed transmit data from deep space at a higher information rate.

To improve upon the rate at which data flows between spacecraft and antennas on Earth, DSOC uses laser signals rather than the radio signals currently used to transmit data. Radio signals and laser signals are both part of the electromagnetic spectrum and travel at the same speed – the speed of light – but they have different wavelengths. The DSOC lasers transmit data in the near-infrared portion of the electromagnetic spectrum, so their wavelength is shorter than radio waves, and they have a higher frequency.

Each type of wave on the electromagnetic spectrum is represented with a wavy line. Each wave – radio, microwave, infrared, visible, ultraviolet, x-ray, and gamma ray – is between a range of wavelengths that get shorter (from >100,000,000 nm to <.01 nm) and frequencies that get higher (from <3x10^9 to >3x10^19 Hz) from left to right. Visible light makes up a relatively tiny portion of the full spectrum.

This chart compares the wavelength and frequency range of each kind of wave on the electromagnetic spectrum. Note: The graphic representations are not to scale. Image credit: NASA/JPL-Caltech | + Expand image | › Download low-ink version for printing

Since there are more infrared than radio wavelengths over a particular distance, more data can be sent over the same distance using infrared. And since the speed of infrared and radio waves is equal to the speed of light, this also means that more data can be sent in the same length of time using infrared.

As a result, DSOC’s maximum information rate is around 267 megabits per second (Mbps), faster than many terrestrial internet signals. At that high data rate, the 153.6 megabit cat video took only 0.58 seconds to transmit and another 101 seconds to travel the 19 million miles to Earth at the speed of light. Instead, if we had sent the cat video using Psyche's radio transmitter, which has a data rate of 360 kilobits per second, it would have taken 426 seconds to transmit the video, plus the same speed-of-light travel time, to get to Earth.

Here's how DSOC aims to revolutionize deep space communications. | Watch on YouTube

This kind of spacecraft communications isn't without its challenges. Accurately pointing the narrow laser beam is one of the greatest challenges of optical communications.

DSOC consists of a "flight laser transceiver" aboard the Psyche spacecraft – which is currently on its journey to study the asteroid 16-Psyche – and a receiving station on Earth. The flight transceiver is a 22-centimeter-diameter apparatus that can both transmit and receive signals. Its maximum transmitter strength is a low 4 Watts. For the December 2023 test, a 160-Watt beacon signal was transmitted to the DSOC flight transceiver by a 1-meter telescope located at JPL's Table Mountain facility near Wrightwood, California. This beacon signal was used by the Psyche spacecraft as a pointing reference so it could accurately aim the DSOC transceiver at the Earth receiving station – the 5-meter Hale telescope at Caltech’s Palomar Observatory near San Diego.

This animation shows how DSOC's laser signals are sent between the Psyche spacecraft and ground stations on Earth - first as a pointing reference to ensure accurate aiming of the narrow laser signal and then as a data transmission to the receiving station. | Watch on YouTube

When the DSOC laser beam encounters Earth, it is much narrower than a radio signal transmitted from the same distance. In fact, the laser beam is only a few hundred kilometers wide when it reaches Earth, in sharp contrast with an approximately 2.5-million-kilometer-wide radio signal. This narrow beam must be pointed accurately enough so it not only intersects Earth, but also overlaps the receiving station. To ensure that the beam will be received at Palomar Observatory, the transmission must be aimed not directly at Earth, but at a point where Earth will be in its orbit when the signal arrives after traveling the great distance from the spacecraft.

What's next for laser communications

Engineers will do additional tests of the DSOC system as the Psyche spacecraft continues its 2.2-billion-mile (3.6-billion-kilometer) journey to its destination in the asteroid belt beyond Mars. Over the next couple of years, DSOC will make weekly contacts with Earth. Visit NASA's DSOC website to follow along as NASA puts the system through its paces to potentially usher in a new means of transmitting data through space.

How does the cat video relate to STEM learning?

The DSOC project provides a wonderful opportunity to help students understand the electromagnetic spectrum and learn about real-world applications of STEM in deep space communications. Try out these lessons and resources to get students engaged.

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TAGS: K-12 Education, Educators, Students, Learning Resources, Teaching Resources, DSOC, DSN, Deep Space Network

  • Ota Lutz
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Spikes of light extend from the Sun shining above the glowing blue limb of Earth, as shown from space.

Leap day, Feb. 29, happens every four years because of a mismatch between the calendar year and Earth's orbit. Learn how it works, and get students engaged in leap day STEM.


You may have noticed that there's an extra day on your calendar this year. That's not a typo – it's leap day! Leap day is another name for Feb. 29, a date that typically comes around every four years, during a leap year.

Why doesn't Feb. 29 appear on the calendar every year?

The length of a year is based on how long it takes a planet to revolve around the Sun. Earth takes about 365.2422 days to make one revolution around the Sun. That's about six hours longer than the 365 days that we typically include in a calendar year. As a result, every four years, we have about 24 extra hours that we add to the calendar at the end of February in the form of leap day.

Without leap day, the dates of annual events, such as equinoxes and solstices, would slowly shift to later in the year, changing the dates of each season. After only a century without leap day, summer wouldn’t start until mid-July!

But the peculiar adjustments don't end there. If Earth revolved around the Sun in exactly 365 days and six hours, this system of adding a leap day every four years would need no exceptions. However, Earth takes a little less time than that to orbit the Sun. Rounding up and inserting a 24-hour leap day every four years adds about 45 extra minutes to every four-year leap cycle. That adds up to about three days every 400 years. To correct for that, years that are divisible by 100 don't have leap days unless they’re also divisible by 400.

If you do the math, you'll see that the year 2000 was a leap year, but 2100, 2200 and 2300 will not be.

Have students learn more about leap years with this article from NASA's Space Place, then have them do the math for themselves with this leap day problem set. You can also have students write a letter or poem to be opened on the next leap day or get them learning about orbits across the solar system.

And since we've got an extra 24 hours this year, don't forget to take a little time to relax!

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TAGS: K-12 Education, Math, Leap Day, Leap Year, Events, Space, Educators, Teachers, Parents, Students, STEM, Lessons, Earth Science, Earth

  • Lyle Tavernier
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Share your feedback in this 5-minute survey to help JPL Education improve our offerings. 


We're working on improving our offerings for educators, students, and families, and we want to hear from you!

This 5-minute survey will help us learn about what resources and offerings you use the most and what you'd like to see us do more of or do differently. Plus, we'd love to hear about the ways you're using JPL Education resources and any impact they've had on you.

This survey is completely anonymous, but you do have the option to share your email address if you would like to be contacted about future opportunities to provide feedback. 

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  • NASA/JPL Edu
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A spacecraft with a cylindrical body topped by a flat rectangular solar panel is shown among a starry backdrop interspersed with fuzzy blobs representing dark matter.

Learn about a new mission seeking to understand some of the greatest mysteries of our universe, and explore hands-on teaching resources that bring it all down to Earth.


Scientists may soon uncover new insights about some of the most mysterious phenomena in our universe with the help of the newly launched Euclid mission. Built and managed by the European Space Agency, Euclid will use a suite of instruments developed, in part, by NASA's Jet Propulsion Laboratory to explore the curious nature of dark energy and dark matter along with their role in the expansion and acceleration of our universe.

Read on to learn how the Euclid mission will probe these cosmological mysteries. Then, find out how to use demonstrations and models to help learners grasp these big ideas.

Why It’s Important

No greater question in our universe promotes wonder in scientists and non-scientists alike than that of the origin of our universe. The Euclid mission will allow scientists to study the nearly imperceptible cosmic components that may hold exciting answers to this question.

Edwin Hubble's observations of the expanding universe in the 1920s marked the beginnings of what's now known as the big-bang theory. We've since made monumental strides in determining when and how the big bang would have taken place by looking at what's known as cosmic background radiation using instruments such as COBE and WMAP in 1989 and 2001, respectively. However, there's one piece of Hubble's discovery that still has scientists stumped: our universe is not only expanding, but as scientists discovered in 1998, that expansion is also accelerating.

This side by side comparison shows a constant rate of expansion of the universe, represented by the expanding sphere on the left, and an accelerating rate of expansion of the universe, represented by the expanding sphere on the right. Each dot on the spheres represents a galaxy and shows how galaxies move apart from each other faster in the universe that has an accelerating rate of expansion. | Watch on YouTube

How can this be? It makes intuitive sense that, regardless of the immense force of the big bang that launched all matter across the known universe 13.8 billion years ago, that matter would eventually come to a rest and possibly even start to collapse. Instead, it's as if we've dropped a glass onto the ground and discovered that the shards are flying away from us faster and faster into perpetuity.

A sideways funnel that fans out at one end encapsulates an illustration of the history of the universe starting with the Big Bang 13.7 billion years ago through the first stars, the development of galaxies, and accelerated expansion.

An illustrated timeline of the universe. Credit: WMAP | + Expand image

Scientists believe that answers may lie in two yet-to-be-understood factors of our universe: dark matter and dark energy. Dark matter is unlike the known matter we experience here on Earth, such as what's found on the periodic table. We can't actually see dark matter; we can only infer its presence. It has mass and therefore gravity, making it an attractive force capable of pulling things together. Amazingly, dark matter makes up roughly 27% of the known universe compared with the much more modest 5% of "normal matter" that we experience day to day. However, dark matter is extremely dilute throughout the universe with concentrations of 105 particles per cubic meter.

This animated pie chart shows rounded values for the three known components of the universe: visible matter (5%), dark matter (27%), and dark energy (68%). Credit: NASA's Goddard Space Flight Center | › Full video and caption

In opposition to the attractive force of dark matter, we have dark energy. Dark energy is a repulsive force and makes up roughly 68% of energy in the known universe. Scientists believe that the existence of dark energy and the amount of repulsion it displays compared with dark matter is what's causing our universe to not only expand, but also to expand faster and faster.

Dr. Jennifer Wiseman, a senior project scientist with the Hubble Space Telescope mission, explains how the mission has been helping scientists learn more about dark energy. Credit: NASA Goddard | Watch on YouTube

But to truly understand this mysterious force and how it interacts with both dark matter and normal matter, scientists will have to map barely detectable distortions of light traversing the universe, carefully measuring how that light changes over time and distance in every direction. As JPL Astrophysicist Jason Rhodes explains, “Dark energy has such a subtle effect that we need to survey billions of galaxies to adequately map it.”

And that's where Euclid comes in.

How It Works

The European Space Agency and NASA each contributed to the development of the Euclid mission, which launched from Cape Canaveral Space Force Station in Florida on July 1. The spacecraft consists of a 1.2-meter (48-inch) space telescope and two science instruments: an optical camera and a near-infrared camera that also serves as a spectrometer. These instruments will provide a treasure trove of data for scientists of numerous disciplines, ranging from exoplanet hunters to cosmologists.

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

This infographic is divided into three sectionss. The first describes how wavelengths increase over time, shifting from blue to yellow to red as objects in space get older and farther away. The second shows how light stretched by the expansion of space becomes redder and enters the infrared portion of the electromagnetic spectrum. The third shows how telescopes like Roman use infrared detectors to see this ancient light and learn about the early universe.

This graphic illustrates how cosmological redshift works and how it offers information about the universe’s evolution. Credit: NASA, ESA, Leah Hustak (STScI) | › Full image and caption

As Gisella de Rosa at the Space Telescope Science Institute explains, “The ancillary science topics we will be able to study with Euclid range from the evolution of the objects we see in the sky today to detecting populations of galaxies and creating catalogs for astronomers. The data will serve the entire space community.”

The cameras aboard Euclid will operate at 530-920 nanometers (optical light) and at 920-2020 nanometers (near infrared) with each boasting more than 576 million and 65 million pixels, respectively. These cameras are capable of measuring the subtle changes to the light collected from celestial objects and can determine the distances to billions of galaxies across a survey of 15,000 square degrees – one-third of the entire sky.

Meanwhile, Euclid's spectrometer will collect even more detailed measurements of the distance to tens of millions of galaxies by looking at redshift. Redshift describes how wavelengths of light change ever so slightly as objects move away from us. It is a critical phenomenon for measuring the speed at which our universe is expanding. Similar to the way sound waves change as a result of the Doppler effect, wavelengths of light are compressed to shorter wavelengths (bluer) as something approaches you and extended to longer wavelengths (redder) as it moves away from you. As determined by a Nobel Prize winning team of astronomers, our universe isn’t just red-shifting over time, distant objects are becoming redder faster.

Euclid will measure these incredibly minuscule changes in wavelength for objects near and far, providing an accurate measurement of how the light has changed as a factor of time and distance and giving us a rate of acceleration of the universe. Furthermore, Euclid will be able to map the relative densities of dark matter and normal matter as they interact with dark energy, creating unevenly distributed pockets of more attractive forces. This will allow scientists to identify minute differences in where the universe is expanding by looking at the way that light is altered or "lensed."

The multi-dimensional maps created by Euclid – which will include depth and time in addition to the height and width of the sky – will inform a complementary mission already in development by NASA, the Nancy Grace Roman Space Telescope. Launching in 2026, this space telescope will look back in time with even greater detail, targeting areas of interest provided by Euclid. The telescope will use instruments with higher sensitivity and spatial resolution to peer deeper into redshifted and faint galaxies, building on the work of Euclid to look farther into the accelerating universe. As Caltech’s Gordon Squires describes it: “We’re trying to understand 90% of our entire universe. Both of these telescopes will provide essential data that will help us start to uncover these colossal mysteries.”

Teach It

The abstract concepts of the scope and origin of our universe and the unimaginable scale of cosmology can be difficult to communicate to learners. However, simple models and simulations can help make these topics more tangible. See below to find out how, plus explore more resources about our expanding universe.

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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: K-12 Education, Teaching, Teachers, Educators, Resources, Universe, Dark Matter, Dark Energy, Euclid, Nancy Grace Roman Space Telescope, Universe of Learning

  • Brandon Rodriguez
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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.

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

  • Lyle Tavernier
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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.

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

  • Ota Lutz
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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:

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

  • Lyle Tavernier
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Collage of images from the events and lessons featured in this article.

With 180 lessons in our online catalog, you can explore Earth and space with us all year long. We show you how with this handy NASA-JPL school year calendar.


We just added the 180th lesson to our online catalog of standards-aligned STEM lessons, which means JPL Education now has a lesson for every day of the school year. To celebrate and help you make the year ahead stellar, we've put together this monthly calendar of upcoming NASA events along with links to our related lessons, Teachable Moments articles, and student projects you can use to engage students in STEM while they explore Earth and space with us all year long.


August

The Voyagers Turn 45

The twin Voyager spacecraft launched in 1977 on a journey to explore the outer planets and beyond – and they're still going. Now more than 12 billion miles (19 billion kilometers) from Earth in a region known as interstellar space, they're the most distant human-made objects in space.

Get a primer on these fascinating spacecraft from Teachable Moments, then use it as a jumping off point for lessons on the scale, size, and structure of our solar system and how we communicate with distant spacecraft.

Lessons & Resources:


September

Rendezvous with an Asteroid

A distant asteroid system 6.8 million miles (11 million kilometers) from Earth was the site of NASA's first attempt at redirecting an asteroid. On September 26, the Double Asteroid Redirection Test, or DART, mission impacted the asteroid Dimorphos in an attempt to alter its speed and path around a larger asteroid known as Didymos. Dimorphos and Didymos do not pose a threat to Earth, which makes them a good proving ground for testing whether a similar technique could be used to defend Earth against potential impacts by hazardous asteroids in the future.

Get a primer on the DART mission and find related resources for the classroom in this article from our Teachable Moments series. Plus, explore our collection of standards-aligned lessons and activities all about asteroids to get students learning about different kinds of space rocks, geology, and meteoroid math.

Lessons & Resources:

A Closer Look at Europa

Just a few days later, on September 29, the Juno spacecraft that had been orbiting Jupiter since 2016 captured the closest views of Jupiter’s moon Europa in more than 20 years. The ice-covered moon is thought to contain a subsurface liquid-water ocean, making it an exciting new frontier in our search for life beyond Earth. NASA's Europa Clipper mission, which is scheduled to launch in 2024 is designed to study the moon in more detail. But until Europa Clipper arrives at the Jovian system in 2030, these observations from Juno are our best chance to get a closer look at this fascinating moon.

Learn more about Europa and why it is interesting to scientists in this talk from our Teaching Space With NASA series featuring a Europa Clipper mission scientist. Then, explore our Ocean Worlds Lesson Collection for ideas on making classroom connections.

Lessons & Resources:


October

Celebrate Halloween Like a Space Explorer

The month of October is the perfect time to get students exploring our STEM activities with a Halloween twist. Students can learn how to carve a pumpkin like a JPL engineer, take a tour of mysterious locations throughout the solar system, and dig into the geology inside their Halloween candy.

October 31 is also JPL's 86th birthday, which makes October a great time to learn more about JPL history, including the team of female mathematicians known as "human computers" who performed some of the earliest spacecraft-tracking calculations and the Laboratory's role in launching the first U.S. space satellite.

Lessons & Resources:


November

Watch a Total Lunar Eclipse

Look up in the early morning hours of November 8 to watch one of the most stunning spectacles visible from Earth: a total lunar eclipse. This one will be viewable in North and South America, as well as Asia and Australia.

Learn more about lunar eclipses and how to watch them from our Teachable Moments series. Then, get students of all ages outside and observing the Moon with lessons on moon phases and the hows and whys of eclipses. Students can even build a Moon calendar so they always know when and where to look for the next eclipse.

Lessons & Resources:

Artemis Takes a Giant Leap

NASA is making plans to send astronauts back to the Moon for the first time since 1972 – this time to establish a sustainable presence and prepare for future human missions to Mars. The first major step is Artemis I, which is testing three key components required to send astronauts beyond the Moon: the Orion spacecraft, the Space Launch System, or SLS, rocket and the ground systems at Kennedy Space Center in Florida. The uncrewed Artemis I mission marks the first test of all three components at once.

Get your K-12 students following along with lessons in rocketry and what it takes to live in space. Plus, register to follow along with the mission with resources and updates from NASA's Office of STEM Engagement.

Lessons & Resources:


December

Satellite Launches on a Mission to Follow the Water

As crucial as water is to human life, did you know that no one has ever completed a global survey of Earth’s surface water? That is about to change with the launch of the SWOT mission. SWOT, which stands for Surface Water Ocean Topography, will use a state-of-the-art radar to measure the elevation of water in major lakes, rivers, wetlands, and reservoirs. It will also provide an unprecedented level of detail on the ocean surface. This data will help scientists track how these bodies of water are changing over time and improve weather and climate models.

Engage your students in learning about Earth’s water budget and how we monitor Earth from space with these lessons. And be sure to check out our Teachable Moments article for more about the SWOT mission and the science of our changing climate.

Prepare for the Science Fair

Before you know it, it'll be science fair time. Avoid the stress of science fair prep by getting students organized and thinking about their projects before the winter recess. Start by watching our video series How to Do a Science Fair Project. A scientist and an engineer from JPL walk your students through all the steps they will need to create an original science fair project by observing the world around them and asking questions. You can also explore our science fair starter pack of lessons and projects to get students generating ideas and thinking like scientists and engineers.

Lessons & Resources:


January

Explore STEM Careers

January is the time when many of us set goals for the year ahead, so it's the perfect month to get students exploring their career goals and opportunities in STEM. Students can learn more about careers in STEM and hear directly from scientists and engineers working on NASA missions in our Teaching Space video series. Meanwhile, our news page has more on what it takes to be a NASA astronaut and what it's like to be a JPL intern.

For students already in college and pursuing STEM degrees, now is the time to start exploring internship opportunities for the summer. The deadline for JPL summer internships is in March, so it's a good idea to refresh your resume and get your application started now. Learn how to stand out with this article on how to get an internship at JPL – which also includes advice for pre-college students.

Resources:


February

Mars Rover Celebrates 2-Year 'Landiversary'

NASA's Perseverance Mars rover celebrates its "landiversary" on February 18, which marks two years since the rover made its nail-biting descent on the Red Planet. The rover continues to explore Jezero Crater using science tools to analyze rocks and soil in search of signs of ancient microbial life. As of this writing, the rover has collected twelve rock core samples that will be sent to Earth by a future mission. Perseverance even witnessed a solar eclipse! Meanwhile, the Ingenuity Mars helicopter, which the rover deployed shortly after landing, has gone on to achieve feats of its own.

The Mission to Mars Student Challenge is a great way to get students of all ages exploring STEM and the Red Planet right along with the Perseverance rover. The challenge includes seven weeks of education content that can be customized for your classroom as well as education plans, expert talks, and resources from NASA.

Lessons & Resources:


March

Take On the Pi Day Challenge

Math teachers, pie-lovers, and pun-aficionados rejoice! March 14 is Pi Day, the annual celebration of the mathematical constant used throughout the STEM world – and especially for space exploration. This year's celebration brings the 10th installment of the NASA Pi Day Challenge, featuring four new illustrated math problems involving pi along with NASA missions and science.

Explore the full collection of pi math lessons, get students learning about how we use pi at NASA, and hear from a JPL engineer on how many decimals of pi we use for space exploration at the links below.

Lessons & Resources:


April

Celebrate Earth Day With NASA

You may not immediately think of Earth science when you think of NASA, but it's a big part of what we do. Earth Day on April 22 is a great time to explore Earth science with NASA, especially as new missions are taking to the skies to study the movements of dust, measure surface water across the planet, and track tiny land movements to better predict natural disasters.

Whether you want to focus on Earth’s surface and geology, climate change, extreme weather, or the water budget, we have an abundance of lessons, student projects and Teachable Moments to guide your way.

Lessons & Resources:


May

Summer Learning Adventures

As the school year comes to a close, send your students off on an adventure of summer learning with our do-it-yourself STEM projects. Additionally, our Learning Space With NASA at Home page and video series is a great resource for parents and families to help direct students' learning during out-of-school time.

Lessons & Resources:

TAGS: K-12 Education, Teachers, Students, Lessons, Resources, Projects, Events, Artemis, Voyager, DART, Asteroids, Europa, Ocean Worlds, Halloween, History, Earth, Climate, SWOT, Lunar Eclipse, Science Fair, Career Advice, Mars, Perseverance, Pi Day, Earth Day, Summer STEM

  • Kim Orr
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