JPL
Careers
Education
Science & Technology
JPL Logo
JPL Logo
Solar System
.

Cassini Catches Titan Naked in the Solar Wind

Jan 28, 2015
This diagram depicts conditions observed by NASA's Cassini spacecraft during a flyby in Dec. 2013, when Saturn's magnetosphere was highly compressed, exposing Titan to the full force of the solar wind.› Full image and caption
Credit: NASA/JPL-Caltech

Researchers studying data from NASA's Cassini mission have observed that Saturn's largest moon, Titan, behaves much like Venus, Mars or a comet when exposed to the raw power of the solar wind.

Researchers studying data from NASA's Cassini mission have observed that Saturn's largest moon, Titan, behaves much like Venus, Mars or a comet when exposed to the raw power of the solar wind. The observations suggest that unmagnetized bodies like Titan might interact with the solar wind in the same basic ways, regardless of their nature or distance from the sun.

Titan is large enough that it could be considered a planet if it orbited the sun on its own, and a flyby of the giant moon in Dec. 2013 simulated that scenario, from Cassini's vantage point. The encounter was unique within Cassini's mission, as it was the only time the spacecraft has observed Titan in a pristine state, outside the region of space dominated by Saturn's magnetic field, called its magnetosphere.

"We observed that Titan interacts with the solar wind very much like Mars, if you moved it to the distance of Saturn," said Cesar Bertucci of the Institute of Astronomy and Space Physics in Buenos Aires, who led the research with colleagues from the Cassini mission. "We thought Titan in this state would look different. We certainly were surprised," he said.

The solar wind is a fast-flowing gale of charged particles that continually streams outward from the sun, flowing around the planets like islands in a river. Studying the effects of the solar wind at other planets helps scientists understand how the sun's activity affects their atmospheres. These effects can include modification of an atmosphere's chemistry as well as its gradual loss to space.

Titan spends about 95 percent of the time within Saturn's magnetosphere. But during a Cassini flyby on Dec. 1, 2013, the giant moon happened to be on the sunward side of Saturn when a powerful outburst of solar activity reached the planet. The strong surge in the solar wind so compressed the sun-facing side of Saturn's magnetosphere that the bubble's outer edge was pushed inside the orbit of Titan. This left the moon exposed to, and unprotected from, the raging stream of energetic solar particles.

Using its magnetometer instrument, which is akin to an equisitely sensitive compass, Cassini has observed Titan many times during the mission's decade in the Saturn system, but always within Saturn's magnetosphere. The spacecraft has not been able to detect a magnetic field coming from Titan itself. In its usual state, Titan is cloaked in Saturn's magnetic field.

This time the influence of Saturn was not present, allowing Cassini's magnetometer to observe Titan as it interacted directly with the solar wind. The special circumstance allowed Bertucci and colleagues to study the shockwave that formed around Titan where the full-force solar wind rammed into the moon's atmosphere.

At Earth, our planet's powerful magnetic field acts as a shield against the solar wind, helping to protect our atmosphere from being stripped away. In the case of Venus, Mars and comets -- none of which is protected by a global magnetic field -- the solar wind drapes around the objects themselves, interacting directly with their atmospheres (or in the comet's case, its coma). Cassini saw the same thing at Titan.

Researchers thought they would have to treat Titan's response to the solar wind with a unique approach because the chemistry of the hazy moon's dense atmosphere is highly complex. But Cassini's observations of a naked Titan hinted at a more elegant solution. "This could mean we can use the same tools to study how vastly different worlds, in different parts of the solar system, interact with the wind from the sun," Bertucci said.

Bertucci noted that the list of similarly unmagnetized bodies might include the dwarf planet Pluto, to be visited this year for the first time by NASA's New Horizons spacecraft.

"After nearly a decade in orbit, the Cassini mission has revealed once again that the Saturn system is full of surprises," said Michele Dougherty, principal investigator of the Cassini magnetometer at Imperial College, London. "After more than a hundred flybys, we have finally encountered Titan out in the solar wind, which will allow us to better understand how such moons maintain or lose their atmospheres."

The new research is published today in the journal Geophysical Research Letters.

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. JPL designed, developed and assembled the Cassini orbiter. The magnetometer team is based at Imperial College, London, U.K.

More information about Cassini:

http://www.nasa.gov/cassini

and

http://saturn.jpl.nasa.gov

News Media Contact

Preston Dyches

818-354-7013

preston.dyches@jpl.nasa.gov

2015-038

Related News

Solar System .

NASA’s Deep Space Network Welcomes a New Dish to the Family

Mars .

6 Things to Know About NASA’s Mars Helicopter on Its Way to Mars

Mars .

NASA to Host Virtual Briefing on February Perseverance Mars Rover Landing

Mars .

NASA InSight’s ‘Mole’ Ends Its Journey on Mars

Mars .

Mars 2020 Perseverance Rover to Capture Sounds From the Red Planet

Solar System .

NASA’s Juno Mission Expands Into the Future

Mars .

NASA’s Curiosity Rover Reaches Its 3,000th Day on Mars

Mars .

NASA Extends Exploration for Two Planetary Science Missions

Mars .

Celebrate the Perseverance Rover Landing With NASA's Student Challenge

Mars .

7 Things to Know About the NASA Rover About to Land on Mars

Explore More

Image .

Juno's Mission Goes On

Topic .

Solar System

Image .

A Hot Spot on Jupiter

Image .

Jupiter's Storm Oval BA As Viewed By An Artist

Image .

Two Views of Jupiter Hot Spot

Image .

A Jupiter Circumpolar Cyclone

Image .

Jupiter North Pole Detail

Video .

What's Up - January 2021

Image .

All Eight Northern Circumpolar Cyclones in 2020

Image .

Tracking Clouds on Jupiter

About JPL
Who We Are
Executive Council
Directors of JPL
JPL History
Documentary Series
Virtual Tour
Annual Reports
Missions
All
Current
Past
Future
News
All
Earth
Mars
Solar System
Universe
Technology
Galleries
Images
Videos
Audio
Podcasts
Infographics
Engage
JPL and the Community
Lecture Series
Public Tours
Events
Team Competitions
JPL Speakers Bureau
Topics
Solar System
Mars
Earth
Climate Change
Stars and Galaxies
Exoplanets
Technology
JPL Life
For Media
Contacts and Information
Press Kits
More
Asteroid Watch
Robotics at JPL
Subscribe to Newsletter
Social Media
Get the Latest from JPL
Follow Us

JPL is a federally funded research and development center managed for NASA by Caltech.

More from JPL
Careers Education Science & Technology Acquisitions JPL Store
Careers
Education
Science & Technology
Acquisitions
JPL Store
Related NASA Sites
Basics of Spaceflight
Climate Kids
Earth / Global Climate Change
Exoplanet Exploration
Mars Exploration
Solar System Exploration
Space Place
NASA's Eyes Visualization Project
Voyager Interstellar Mission
NASA
Caltech
Privacy
Image Policy
FAQ
Feedback
Site Manager: Veronica McGregor
Site Editors: Tony Greicius, Randal Jackson, Naomi Hartono