* Astronomy

Blobrana · L

RE: Mars - more water

Blobrana · L

The Phoenix spacecraft on Mars has detected snow above its landing site.
The US robot used its lidar instrument to probe the structure of clouds and saw large water ice-crystals falling through the Martian "air".
The instrument, which works by scattering pulses of laser light off particles in the sky, did not follow the snow to the ground.

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Blobrana · L

Scientists studying the Martian landscape said yes, a river ran through it and not just one. The ancient red planet also seems to have experienced rain, they say.
The rivers may have cut the deep valleys in the Martian highlands near the equator, and also left calling cards elsewhere. Three Mars spacecraft spotted signs of fan-shaped river deltas inside ancient craters which some valleys clearly flow into.

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Blobrana · L

Was Mars wet for a billion years longer?
Scientists think rains and floods persisted into more recent Mars' history
Parts of ancient Mars may have been wet for a billion years longer than scientists previously thought, a new study of images of the red planet's surface suggests.

Along with Earth and the other inner planets of our solar system, Mars formed about 4.5 billion years ago. Scientists have long known that flowing water formed many of the features seen on Mars today, but previous studies suggested that water runoff from precipitation had ceased after the first billion years of Mars' history, called the Noachian Epoch.
But one team of scientists thinks these rains and floods persisted into more recent geologically speaking periods in Mars' history.

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Blobrana · L

Ancient features on the surface of Mars called valley networks may well have been carved by recurrent floods during a long period when the martian climate may have been much like that of some arid or semiarid regions on Earth. An alternative theory that the valleys were carved by catastrophic flooding over a relatively short time is not supported by the new results.

Often cited as evidence that Mars once had a warm environment with liquid water on the surface, valley networks are distinctive features of the martian landscape. In the new study, researchers used sophisticated computer models to simulate the processes that formed these features.

"Our results argue for liquid water being stable at the surface of Mars for prolonged periods in the past" - Charles Barnhart, a graduate student in Earth and planetary sciences at the University of California, Santa Cruz.

Barnhart conducted the study as a Graduate Student Research Program scholar at NASA Ames Research Center, working with NASA planetary scientist Jeffrey Moore and Alan Howard of the University of Virginia. A paper describing their findings has been accepted for publication in the Journal of Geophysical Research - Planets and is currently available online.

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-- Edited by Blobrana at 18:38, 2008-09-17

Blobrana · L

Mars once hosted vast lakes, flowing rivers and a variety of other wet environments that had the potential to support life, according to two new studies based on data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) and other instruments on board NASAs Mars Reconnaissance Orbiter (MRO).

A colour-enhanced image of the delta in Jezero Crater, which once held a lake. Researchers led by CRISM team member and Brown graduate student Bethany Ehlmann report that ancient rivers ferried clay-like minerals (shown in green) into the lake, forming the delta. Clays tend to trap and preserve organic matter, making the delta a good place to look for signs of ancient life.
Credit: NASA/JPL/JHUAPL/MSSS/Brown University)

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Blobrana · L

A new analysis of Martian soil data led by University of California, Berkeley, geoscientists suggests that there was once enough water in the planet's atmosphere for a light drizzle or dew to hit the ground, leaving tell-tale signs of its interaction with the planet's surface.
The study's conclusion breaks from the more dominant view that the liquid water that once existed during the red planet's infancy came mainly in the form of upwelling groundwater rather than rain.
To come up with their conclusions, the UC Berkeley-led researchers used published measurements of soil from Mars that were taken by various NASA missions: Viking 1, Viking 2, Pathfinder, Spirit and Opportunity. These five missions provided information on soil from widely distant sites surveyed between 1976 and 2006.

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Blobrana · L

A clash of lava and ice may have unleashed a vast flood on Mars not long ago, a fresh look at surface images suggests.
Mars's ice caps are scarred by huge chasms, but until recently no one knew for sure what happened to their contents. Now a team led by Niels Hovius of the University of Cambridge reckon they have found volcanic craters in exposed rock at one chasm's base and scours that suggest huge flows of water.
The craters are between 20,000 and 10 million years old, suggesting liquid water was present on Mars's surface relatively recently. The wet area beneath the ice could have been a temporary haven for life.

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Blobrana · L

Were the northern plains of Mars submerged in a vast flood as recently as 20,000 years ago? Geologists claim to have found evidence of a recent volcanic eruption under the ice cap that could have created a wall of water 200 metres high and 35 kilometres wide.
Signs of volcanic activity and flowing mel****er have been found before, but the new study links the two together with strong geological evidence, bolstering theories that water was the chief sculptor of the huge chasms in the northern martian ice cap.

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Blobrana · L

Martian megafloods