Confirmed: Water Once Flowed On Mars

An anonymous reader writes "A new study based on observations last September by the Curiosity rover on Mars has confirmed that pebble-containing slabs of rock found on the Martian surface were part of an ancient streambed. The work provides some of the most definitive evidence yet that water once flowed on Mars. '[The pebbles'] smooth appearance is identical to gravels found in rivers on Earth. Rock fragments that bounce along the bottom of a stream of water will have their edges knocked off, and when these pebbles finally come to rest they will often align in a characteristic overlapping fashion. ...It is confirmation that water has played its part in sculpting not only this huge equatorial bowl but by implication many of the other landforms seen on the planet.' According to NASA, 'The stream carried the gravels at least a few miles, or kilometers, the researchers estimated. The atmosphere of modern Mars is too thin to make a sustained stream flow of water possible, though the planet holds large quantities of water ice. Several types of evidence have indicated that ancient Mars had diverse environments with liquid water. However, none but these rocks found by Curiosity could provide the type of stream flow information published this week. Curiosity's images of conglomerate rocks indicate that atmospheric conditions at Gale Crater once enabled the flow of liquid water on the Martian surface.'"

Comments

Water in particular?

[Anonymous Coward]

Perhaps I'm missing something, but the evidence cited in the article only seems to show that liquid of some kind once flowed on Mars. What further evidence do we have to think that it was water in particular?

Re:Water in particular?

[steelfood]

What other liquid did you have in mind? Water is about the simplest, most abundant, and most versatile liquid out there. Most other naturally-occurring liquids are not liquids in the Martian temperature range, or too complex for there to be a significant amount of (and this applies to the entire universe in general as well, though there may be localized anomolies).

Unless you're positing that it was something organic like oil, or artificial like formaldehyde, there's no other likely candidate liquid that's abundant, operates at those temperatures, and with that viscosity. Don't forget that CO2, the only other abundant substance on Mars, subliminates under 5 atm, and we know the Martian atmospheric pressure is lighter than ours.

How does this confirm it was water?

[Lucas123]

It could have been any liquid with similar viscosity.

Re:What happened to it?

[Anonymous Coward]

That is how religions get formed.