Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. 24/7 Space News .




SATURN DAILY
River networks on Titan point to a puzzling geologic history
by Jennifer Chu for MIT News
Cambridge MA (SPX) Jul 23, 2012


Images from the Cassini mission show river networks draining into lakes in Titan's north polar region. Image: NASA/JPL/USGS.

For many years, Titan's thick, methane- and nitrogen-rich atmosphere kept astronomers from seeing what lies beneath. Saturn's largest moon appeared through telescopes as a hazy orange orb, in contrast to other heavily cratered moons in the solar system. In 2004, the Cassini-Huygens spacecraft - a probe that flies by Titan as it orbits Saturn - penetrated Titan's haze, providing scientists with their first detailed images of the surface.

Radar images revealed an icy terrain carved out over millions of years by rivers of liquid methane, similar to how rivers of water have etched into Earth's rocky continents.

While images of Titan have revealed its present landscape, very little is known about its geologic past.

Now researchers at MIT and the University of Tennessee at Knoxville have analyzed images of Titan's river networks and determined that in some regions, rivers have created surprisingly little erosion.

The researchers say there are two possible explanations: either erosion on Titan is extremely slow, or some other recent phenomena may have wiped out older riverbeds and landforms.

"It's a surface that should have eroded much more than what we're seeing, if the river networks have been active for a long time," says Taylor Perron, the Cecil and Ida Green Assistant Professor of Geology at MIT. "It raises some very interesting questions about what has been happening on Titan in the last billion years."

What accounts for a low crater count?
Compared to most moons in our solar system, Titan is relatively smooth, with few craters pockmarking its facade. Titan is around four billion years old, about the same age as the rest of the solar system. But judging by the number of craters, one might estimate that its surface is much younger, between 100 million and one billion years old.

What might explain this moon's low crater count? Perron says the answer may be similar to what happens on Earth.

"We don't have many impact craters on Earth," Perron says. "People flock to them because they're so few, and one explanation is that Earth's continents are always eroding or being covered with sediment. That may be the case on Titan, too."

For example, plate tectonics, erupting volcanoes, advancing glaciers and river networks have all reshaped Earth's surface over billions of years. On Titan, similar processes - tectonic upheaval, icy lava eruptions, erosion and sedimentation by rivers - may be at work.

But identifying which of these geological phenomena may have modified Titan's surface is a significant challenge.

Images generated by the Cassini spacecraft, similar to aerial photos but with much coarser resolution, are flat, depicting terrain from a bird's-eye perspective, with no information about a landform's elevation or depth.

"It's an interesting challenge," Perron says. "It's almost like we were thrown back a few centuries, before there were many topographic maps, and we only had maps showing where the rivers are."

Charting a river's evolution

Perron and MIT graduate student Benjamin Black set out to determine the extent to which river networks may have renewed Titan's surface.

The team analyzed images taken from Cassini-Huygens, and mapped 52 prominent river networks from four regions on Titan. The researchers compared the images with a model of river network evolution developed by Perron.

This model depicts the evolution of a river over time, given variables such as the strength of the underlying material and the rate of flow through the river channels. As a river erodes slowly through the ice, it transforms from a long, spindly thread into a dense, treelike network of tributaries.

Black compared his measurements of Titan's river networks with the model, and found the moon's rivers most resembled the early stages of a typical terrestrial river's evolution.

The observations indicate that rivers in some regions have caused very little erosion, and hence very little modification of Titan's surface.

"They're more on the long and spindly side," Black says. "You do see some full and branching networks, and that's tantalizing, because if we get more data, it will be interesting to know whether there really are regional differences."

Going a step further, Black compared Titan's images with recently renewed landscapes on Earth, including volcanic terrain on the island of Kauai and recently glaciated landscapes in North America.

The river networks in those locations are similar in form to those on Titan, suggesting that geologic processes may have reshaped the moon's icy surface in the recent past.

"It's a weirdly Earth-like place, even with this exotic combination of materials and temperatures," Perron says. "And so you can still say something definitive about the erosion. It's the same physics."

This research was supported by NASA's Cassini Data Analysis Program. A paper detailing the group's findings will appear in the Journal of Geophysical Research-Planets.

.


Related Links
Massachusetts Institute of Technology
Explore The Ring World of Saturn and her moons
Jupiter and its Moons
The million outer planets of a star called Sol
News Flash at Mercury






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





SATURN DAILY
Cassini Spots Daytime Lightning on Saturn
Pasadena CA (JPL) Jul 20, 2012
Saturn was playing the lightning storm blues. NASA's Cassini spacecraft has captured images of last year's storm on Saturn, the largest storm seen up-close at the planet, with bluish spots in the middle of swirling clouds. Those bluish spots indicate flashes of lightning and mark the first time scientists have detected lightning in visible wavelengths on the side of Saturn illuminated by the sun ... read more


SATURN DAILY
Plans to revisit Moon impeded by financial difficulties

Russia says no manned moon shots till 2018

ESA to catch laser beam from Moon mission

Researchers Estimate Ice Content of Crater at Moon's South Pole

SATURN DAILY
ExoMars program gathers strength

Opportunity Runs the First Martian Marathon

NASA Conducts Mission Simulations In Hawaii

Opportunity Continues to Explore Rocks on the Rim of Endeavour Crater

SATURN DAILY
New York museum opens space shuttle Enterprise to public

Listening to the past and talking to the future

NASA and ATK Complete Space Act Agreement

NASA Completes Another Successful Orion Parachute Test

SATURN DAILY
Looking Forward to Shenzhou 10

Astronauts in good shape after return

Shenzhou mission sparks 'science fever'

China Beats Russia on Space Launches

SATURN DAILY
Japanese Rocket Sends Cargo to ISS

Japan sends cargo to space station

Japan cargo ship heads to space station

New crew docks with space station: Russia

SATURN DAILY
The Spaceport maintains its mission cadence for Ariane 5 flights

S. Korea plans fresh rocket launch in October

NASA Selects Launch Services Contract for Jason-3 Mission

NASA Selects Launch Services Contract for Three Missions

SATURN DAILY
UCF Discovers Exoplanet Neighbor

Can Astronomers Detect Exoplanet Oceans

The Mysterious Case of the Disappearing Dust

Study in Nature sheds new light on planet formation

SATURN DAILY
Samsung records robust sales of latest smartphone

WTO to examine China rare earths dispute, says source

US defends suit on Apple, e-books amid criticism

New Notre Dame research raises questions about iris recognition systems




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement