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

New Models Suggest Titan Lakes Are Explosion Craters

Sep 09, 2019
This artist's concept of a lake at the north pole of Saturn's moon Titan illustrates raised rims and rampartlike features such as those seen by NASA's Cassini spacecraft around the moon's Winnipeg Lacus.› Full image and caption
Credit: NASA/JPL-Caltech

A new theory, based on radar data from NASA's Cassini mission, proposes that some of Titan's lakes formed when pockets of nitrogen blew out basins that filled with methane.

Using radar data from NASA's Cassini spacecraft, recently published research presents a new scenario to explain why some methane-filled lakes on Saturn's moon Titan are surrounded by steep rims that reach hundreds of feet high. The models suggests that explosions of warming nitrogen created basins in the moon's crust.

Titan is the only planetary body in our solar system other than Earth known to have stable liquid on its surface. But instead of water raining down from clouds and filling lakes and seas as on Earth, on Titan it's methane and ethane - hydrocarbons that we think of as gases but that behave as liquids in Titan's frigid climate.

Most existing models that lay out the origin of Titan's lakes show liquid methane dissolving the moon's bedrock of ice and solid organic compounds, carving reservoirs that fill with the liquid. This may be the origin of a type of lake on Titan that has sharp boundaries. On Earth, bodies of water that formed similarly, by dissolving surrounding limestone, are known as karstic lakes.

The new, alternative models for some of the smaller lakes (tens of miles across) turns that theory upside down: It proposes pockets of liquid nitrogen in Titan's crust warmed, turning into explosive gas that blew out craters, which then filled with liquid methane. The new theory explains why some of the smaller lakes near Titan's north pole, like Winnipeg Lacus, appear in radar imaging to have very steep rims that tower above sea level - rims difficult to explain with the karstic model.

The radar data were gathered by the Cassini Saturn Orbiter - a mission managed by NASA's Jet Propulsion Laboratory in Pasadena, California - during its last close flyby of Titan, as the spacecraft prepared for its final plunge into Saturn's atmosphere two years ago. An international team of scientists led by Giuseppe Mitri of Italy's G. d'Annunzio University became convinced that the karstic model didn't jibe with what they saw in these new images.

"The rim goes up, and the karst process works in the opposite way," Mitri said. "We were not finding any explanation that fit with a karstic lake basin. In reality, the morphology was more consistent with an explosion crater, where the rim is formed by the ejected material from the crater interior. It's totally a different process."

The work, published Sept. 9 in Nature Geosciences, meshes with other Titan climate models showing the moon may be warm compared to how it was in earlier Titan "ice ages."

Over the last half-billion or billion years on Titan, methane in its atmosphere has acted as a greenhouse gas, keeping the moon relatively warm - although still cold by Earth standards. Scientists have long believed that the moon has gone through epochs of cooling and warming, as methane is depleted by solar-driven chemistry and then resupplied.

In the colder periods, nitrogen dominated the atmosphere, raining down and cycling through the icy crust to collect in pools just below the surface, said Cassini scientist and study co-author Jonathan Lunine of Cornell University in Ithaca, New York.

"These lakes with steep edges, ramparts and raised rims would be a signpost of periods in Titan's history when there was liquid nitrogen on the surface and in the crust," he noted. Even localized warming would have been enough to turn the liquid nitrogen into vapor, cause it to expand quickly and blow out a crater.

"This is a completely different explanation for the steep rims around those small lakes, which has been a tremendous puzzle," said Cassini Project Scientist Linda Spilker of JPL. "As scientists continue to mine the treasure trove of Cassini data, we'll keep putting more and more pieces of the puzzle together. Over the next decades, we will come to understand the Saturn system better and better."

The Cassini-Huygens mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. JPL, a division of Caltech in Pasadena, manages the mission for NASA's Science Mission Directorate in Washington. JPL designed, developed and assembled the Cassini orbiter. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the U.S. and several European countries.

More information about Cassini can be found here:

https://solarsystem.nasa.gov/cassini

News Media Contact

Gretchen McCartney

Jet Propulsion Laboratory, Pasadena, Calif.

818-393-6215

gretchen.p.mccartney@jpl.nasa.gov

Alana Johnson

NASA Headquarters, Washington

202-672-4780 / 202-358-0668

alana.r.johnson@nasa.gov

2019-183

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