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Titan’s Topography and Shape at the End of the Cassini Mission

Topographic Constraints on the Evolution and Connectivity of Titan’s Lacustrine Basins



Cassini Finds Saturn Moon Has ‘Sea Level’ Like Earth


原題「Cassini Finds Saturn Moon Has ‘Sea Level’ Like Earth」 Credits: NASA/JPL-Caltech/ASI/USGS NASAが発表したタイタンの海面の動画です。 日本語訳した動画も近日中に掲載予定です。

Saturn’s moon Titan may be nearly a billion miles away from Earth, but a recently published paper based on data from NASA’s Cassini spacecraft reveals a new way this distant world and our own are eerily similar. Just as the surface of oceans on Earth lies at an average elevation that we call “sea level,” Titan’s seas also lie at an average elevation.

This is the latest finding that shows remarkable similarities between Earth and Titan, the only other world we know of in our solar system that has stable liquid on its surface. The twist at Titan is that its lakes and seas are filled with hydrocarbons rather than liquid water, and water ice overlain by a layer of solid organic material serves as the bedrock surrounding these lakes and seas.

The new paper, led by Alex Hayes at Cornell University in Ithaca, New York, and published in the journal Geophysical Research Letters, finds that Titan’s seas follow a constant elevation relative to Titan’s gravitational pull — just like Earth’s oceans. Smaller lakes on Titan, it turns out, appear at elevations several hundred feet, or meters, higher than Titan’s sea level. Lakes at high elevation are commonly found on Earth. The highest lake navigable by large ships, Lake Titicaca, is over 12,000 feet [3,700 meters] above sea level.
ニューヨークのイサカにあるコーネル大学のアレックス・ヘイズ博士が主導して地球物理学研究誌に掲載されたこの新しい学術論文は、タイタンの海は地球の海のようにタイタンの重力に比例して一定の海面を維持していることを明らかにしました。 タイタンの小さな湖の湖面は、タイタンの海面よりも数百メートル高い標高で見られます。高々度の標高にある湖は地球上でもよく見ることができます。大型船でも航海できる湖で最も高い標高にあるチチカカ湖は、標高12000フィート(3700m)を超えています。

The new study suggests that elevation is important because Titan’s liquid bodies appear to be connected under the surface in something akin to an aquifer system at Earth. Hydrocarbons appear to be flowing underneath Titan’s surface similar to the way water flows through underground porous rock or gravel on Earth, so that nearby lakes communicate with each other and share a common liquid level.

The paper was based on data obtained by Cassini’s radar instrument until just months before the spacecraft burned up in the Saturn atmosphere last year. It also used a new topographical map published in the same issue of Geophysical Research Letters.

For more details on the two papers, visit:https://news.cornell.edu/stories/2018/01/saturns-moon-titan-sports-earth-features

The Cassini-Huygens mission is a cooperative project of NASA, ESA (European Space Agency) and the Italian Space Agency. NASA’s Jet Propulsion Laboratory, a division of Caltech in Pasadena, manages the mission for NASA’s Science Mission Directorate, 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:https://www.nasa.gov/cassini https://saturn.jpl.nasa.gov

Jia-Rui Cook
Jet Propulsion Laboratory, Pasadena, Calif.

Last Updated: Jan. 18, 2018
Editor: Tony Greicius



Ligeia Mare, shown in here in data obtained by NASA’s Cassini spacecraft, is the second largest known body of liquid on Saturn’s moon Titan. It is filled with liquid hydrocarbons, such as ethane and methane, and is one of the many seas and lakes that bejewel Titan’s north polar region.
Credits: NASA/JPL-Caltech/ASI/Cornell

Titan is the only world in our solar system other than Earth that has stable liquid on its surface. The liquid in Titan’s lakes and seas is mostly methane and ethane.
Credits: NASA/JPL-Caltech/ASI/USGS

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