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5 December 2013 11:26 am ,
Vol. 342 ,
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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ScienceShot: Mars's Frozen Water Cycle
11 June 2010 4:42 pm
River water spills down snow-capped mountains into evaporating oceans and then pours back onto mountaintops as rain or snow. Thus, the water cycle on Earth turns. A new model proposes that a similar sequence may have occurred 3.5 billion years ago on Mars, even though the temperature was a frosty -25°. Many scientists had thought that ancient Mars needed to be warm in order to be wet. But a paper published in this month's Icarus suggests that heavy doses of salts from the mineral-rich martian soil and an atmosphere 10,000 times thicker than present-day allowed flowing rivers and open oceans despite subfreezing temperatures. What did a frozen water cycle look like? Streams gushed from the melting underside of highland glaciers into basins, according to the author, creating ice-packed oceans that sublimated and then snowed back onto the highlands. Over the eons, Mars grew too cold for continuous flows; it's current average temperature is -55°C. But modern satellites have spotted trickles at edges of martian craters (left panel) that look similar to icy brine flows in the Canadian Arctic (right panel), suggesting that small amounts of open water may still exist today and potentially provide a home for extraterrestrial life.
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