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




SATURN DAILY
Mystery of the Missing Waves on Titan
by Dr. Tony Phillips for NASA Science News
Huntsville AL (SPX) Jul 23, 2013


A new ScienceCast video ponders the mystery of the missing waves on Titan.

One of the most shocking discoveries of the past 10 years is how much the landscape of Saturn's moon Titan resembles Earth. Like our own blue planet, the surface of Titan is dotted with lakes and seas; it has river channels, islands, mud, rain clouds and maybe even rainbows. The giant moon is undeniably wet.

The "water" on Titan is not, however, H2O. With a surface temperature dipping 290 degrees F below zero, Titan is far too cold for liquid water. Instead, researchers believe the fluid that sculpts Titan is an unknown mixture of methane, ethane, and other hard-to-freeze hydrocarbons.

The idea that Titan is a wet world with its own alien waters is widely accepted by planetary scientists. Nothing else can account for the observations: NASA's Cassini spacecraft has flown by Titan more than 90 times since 2004, pinging the Moon with radar and mapping its lakes and seas. ESA's Huygens probe parachuted to the surface of Titan in 2005, descending through humid clouds and actually landing in moist soil.

Yet something has been bothering Alex Hayes, a planetary scientist on the Cassini radar team at Cornell University.

If Titan is really so wet, he wonders, "Where are all the waves?"

Here on Earth, bodies of water are rarely still. Breezes blowing across the surface cause waves to ripple and break; raindrops striking sea surfaces also provide some roughness. Yet on Titan, the lakes are eerily smooth, with no discernable wave action down to the millimeter scale, according to radar data from Cassini.

"We know there is wind on Titan," says Hayes. "The moon's magnificent sand dunes [prove] it."

Add to that the low gravity of Titan-only 1/7th that of Earth-which offers so little resistance to wave motion, and you have a real puzzle.

Researchers have toyed with several explanations. Perhaps the lakes are frozen. Hayes thinks that is unlikely, however, "because we see evidence of rainfall and surface temperatures well above the melting point of methane." Or maybe the lakes are covered with a tar-like substance that damps wave motion. "We can't yet rule that out," he adds.

The answer might be found in the results of a study Hayes and colleagues published in the July 2013 online edition of the journal Icarus. Taking into account the gravity of Titan, the low viscosity of liquid hydrocarbons, the density of Titan's atmosphere, and other factors, they calculated how fast wind on Titan would have to blow to stir up waves: A walking-pace breeze of only 1 to 2 mph should do the trick.

This suggests a third possibility: the winds just haven't been blowing hard enough. Since Cassini reached Saturn in 2004, Titan's northern hemisphere (where most of the lakes are located) has been locked in the grip of winter. Cold heavy air barely stirs, and seldom reaches the threshold for wave-making.

But now the seasons are changing. In August 2009 the sun crossed Titan's equator heading north. Summer is coming, bringing light, heat and wind to Titan's lake country.

"According to [climate models], winds will pick up as we approach the solstice in 2017 and should be strong enough for waves," he says.

If waves appear, Cassini should be able to detect them. Radar reflections from wavy lake surfaces can tell researchers a great deal. Wave dimensions, for instance, may reveal the viscosity of the underlying fluid and, thus, its chemical composition. Also, wave speeds would track the speed of the overlying winds, providing an independent check of Titan climate models.

Hayes is excited about "bringing oceanography to another world. All we need now," he says, "are some rough seas."

.


Related Links
Cassini at JPL
Cassini images
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
Revealed - the mystery of the gigantic storm on Saturn
Vitoria-Gasteiz, Spain (SPX) Jun 25, 2013
We now understand the nature of the giant storms on Saturn. Through the analysis of images sent from the Cassini space probe belonging to the North American and European space agencies (NASA and ESA respectively), as well as the computer models of the storms and the examination of the clouds therein, the Planetary Sciences Group of the University of the Basque Country has managed to explain the ... read more


SATURN DAILY
Moon Base and Beyond

First-ever lunar south pole mission could be attempted by 2016

Engine recovered from Atlantic confirmed as Apollo 11 unit

Soviet Moon rover moved farther than thought

SATURN DAILY
Mars Curiosity sets one-day driving distance record

Scientists establish age of Mars meteorites found on Earth

Ancient snowfall likely carved Martian valleys

Reports Detail Mars Rover Clues to Atmosphere's Past

SATURN DAILY
NASA starts building faster-than-light warp engine

Zero Gravity Solutions Commences Trading Of Its Stock

Boeing CST-100 Spacecraft Model Passes Water-Recovery Tests

NASA announces funding for far-out space research

SATURN DAILY
China launches three experimental satellites

Medical quarantine over for Shenzhou-10 astronauts

China's astronauts ready for longer missions

Chinese probe reaches record height in space travel

SATURN DAILY
ISS Research Exposing the Salty Truth of Supercritical Water Transitions

NASA launches new probe of spacesuit failure

Space Station ARISS Software Upgraded by Student For Students

Astronaut's helmet leak forces abrupt end to spacewalk

SATURN DAILY
Alphasat Wears Its Color For Alphabus

Both payloads for Arianespace's next Ariane 5 flight are now mated to the launcher

SpaceX Testing Complete at NASA Glenn's Renovated Facility

Alphasat stacks up

SATURN DAILY
Snow falling around infant solar system

'Water-Trapped' Worlds

A snow line in an infant solar system: Astronomers take first images

In the Zone: The Search For Habitable Planets

SATURN DAILY
Mirror, mirror on the wall, who has the lowest noise of them all

Researchers seek metal-coating secrets of ancient gold-, silversmiths

Magnets make droplets dance

Delayed Shield game gadget to hit market on July 31




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