Dry Ice, not water, creating ‘gullies’ on Mars
Scientists believed it was liquid water streaming on the Mars surface, but new data indicates that it was in fact carbon dioxide.
Water on Mars? Doesn’t sound like it. photo/NASA
Gullies on the Mars surface appeared to be similar to those created here on Earth by water, but new photos collected by NASA’s Mars Reconnaissance Orbiter (MRO) point to a different origin of the gullies. They were formed and are still being formed by carbon dioxide, which freezes in wintertime on Mars, a study published online by the journal Icarus says.
“As recently as five years ago, I thought the gullies on Mars indicated activity of liquid water,” said lead author Colin Dundas of the US Geological Survey’s Astrogeology Science Center in Flagstaff, Arizona.”We were able to get many more observations, and as we started to see more activity and pin down the timing of gully formation and change, we saw that the activity occurs in winter.”
The team, which also included scientist from the Jet Propulsion Laboratory and the University of Arizona, used satellite images of 356 sites on Mats taken by MRO over several years starting 2006. Active formation of gullies was spotted at 38 sites, and the timing of the changes corresponded to cold seasons, when the temperatures would not allow water to be liquid.
The scientists are not quite sure how exactly frozen carbon dioxide, which we call dry ice, can function in this manner, The phenomenon doesn’t occur here on Earth.
Meanwhile a Universe Today July 9 article still promotes the “water on Mars” hypothesis, even with their science fiction and Doctor Who references, with a very contradictory quote (or just outdated) from the U.S. Geological Survey:
“These canyons are believed to have formed when underground water was released from plains materials to the surface, causing the ground to collapse. The water could have been stored within the plains in localized aquifers or as ice, which could have melted due to the heat from nearby volcanoes.”
A portion of a 2014 Mars map showing the area east of Hellas basin, at midsoutherly latitudes. Credit: USGS
