About three billion years ago, all of that liquid water was lost, and Mars became what we call a hyper-arid or polar desert.We show here that even after that and in the recent past, when Mars’ axis tilts to 35 degrees, it heats up sufficiently to melt snow and ice, bringing liquid water back until temperatures drop and it freezes again.PHOTO BY LORENZO DI COLA/GETTY IMAGES
Liquid water flowed on Mars just a few hundred thousand years ago, scientists say .
Thawing ice carved gullies into the landscape where environments could have been habitable – increasing hope of finding evidence of life.
They resemble those in the Dry Valleys of Antarctica – caused by water erosion from melting glaciers.
Ancient lakes once dotted the Red Planet. Vast quantities of water are locked up in sheets of permafrost at the frigid poles,Mars will eventually tilt to 35 degrees again, the researchers said.
Scientists have long wondered whether life ever existed on Mars. NASA’s mantra in the search for extraterrestrials is to follow the water.
On Earth, all lifeforms require water to survive. Among the planets in our solar system, only Earth has a more hospitable climate than Mars. It is suspected Mars once sheltered primitive, bacteria-like organisms.
The U.S. team used a computer model to simulate a ‘sweet spot’ when conditions on Mars allow the planet to get above freezing – leading to periods of flowing liquid water.
The phenomenon could not be explained without the occasional presence of water.
The vast area in the southern hemisphere is known for deposits of minerals – with implications for the possible existence of Martian life.
The study in the journal Science fills missing gaps in the planet’s geological history.
Previous theories suggest gullies were carved by carbon dioxide frost, which evaporates from soil, causing rock and rubble to slide down slopes.
But their height indicated meltwater from glaciers had to be involved because of the distance they traveled down the slopes and levels of erosion.If ice was present, conditions would have been right for melting as temperatures rose above 273 degrees Kelvin, equivalent to about 32 degrees Fahrenheit.
“This means that Mars has been able to create liquid water in enough volume to erode channels within the last million years, which is very recent on the scale of Mars geologic history.”
The researchers had seen similar features firsthand in Antarctica. There, despite the cold temperatures, the sun is able to heat ice just enough for it to melt and for gully activity to occur.
The study also introduces the importance of these gullies in terms of potential targets to visit during future exploration missions.
Produced in association with SWNS Talker
Get news, handpicked just for you, in your box.
