Flowing Water Discovered on Mars

Dolphy writes "BBC News has the latest big scoop on the Mars phenomenon. Researcher Tahirih Motazedian apparently uncovered proof quite some time ago of flowing water and surface change on Mars."

Comments

High res images

[t0qer]

Higher res images

(o) <----put that karma right here :P

Re:Water's not the only liquid in universe

[umofomia]

Mars's surface temperature goes down pretty low at night to some -100 degree Celcius, at which nitrogen (roughly our air) is liquid as well (at earth ground pressures).

Um... the temperature at which nitrogen turns liquid is -195.8 degrees Celcius. With Mars' lower air pressure, I'm sure it's even less.

Meanwhile, even at the poles, Mars does not go below -150 degrees, so there is no place on Mars at which nitrogen will turn into a liquid.

Re:Water's not the only liquid in universe

[panurge]

First, the boiling point of nitrogen is much lower than -100C. And the atmospheric pressure of nitrogen you would need to get a river to flow when the temperature dropped would mean a planet much bigger than Mars.

Second, the remarkable thing about water is that based on simple chemical rules it should not be a liquid at ordinary temperatures: ammonia, with a similar MW, is a gas. It is the strong hydrogen bonding between water molecules that gives it the high melting and boiling points, and the very wide range between them. The ideal liquid to sustain life has a wide range between MP and BP, dissolves a wide range of substances, is itself mostly unreactive, is made from elements common in planets, does not react with oxygen, hydrogen, carbon or sulphur in the liquid state at ordinary pressures, and is easily formed in chemical reactions (which implies a small molecule). Water fits the bill extremely well. Another liquid which is quite good is ethyl alcohol. The other small molecules (ammonia, nitrous oxide, sulphur dioxide, methane, methyl alcohol, hydrogen cyanide) all fall down badly or one or more of the criteria.

Water may not be the only liquid that makes a suitable carrier for life, but it would be really hard to find a more suitable one. Human experiments to use alcohol instead are rarely successful for very long.

Re:Water's not the only liquid in universe

[_Eric]

OK one step further: Martian Atmosphere

Surface pressure: 6.36 mb at mean radius (variable from 4.0 to 8.7 mb depending on season)
[6.9 mb to 9 mb (Viking 1 Lander site)]
Surface density: ~0.020 kg/m3
Scale height: 11.1 km
Total mass of atmosphere: ~2.5 x 1016 kg
Average temperature: ~210 K (-63 C)
Diurnal temperature range: 184 K to 242 K (-89 to -31 C) (Viking 1 Lander site)
Wind speeds: 2-7 m/s (summer), 5-10 m/s (fall), 17-30 m/s (dust storm) (Viking Lander sites)
Mean molecular weight: 43.34 g/mole
Atmospheric composition (by volume):
Major : Carbon Dioxide (CO2) - 95.32% ; Nitrogen (N2) - 2.7%
Argon (Ar) - 1.6%; Oxygen (O2) - 0.13%; Carbon Monoxide (CO) - 0.08%
Minor (ppm): Water (H2O) - 210; Nitrogen Oxide (NO) - 100; Neon (Ne) - 2.5;
Hydrogen-Deuterium-Oxygen (HDO) - 0.85; Krypton (Kr) - 0.3;
Xenon (Xe) - 0.08

So we're talking carbon dioxide. Pressure is 7mb or 7hPa or 0.7kPa (earth pressure beeing around 1000hPa or 100kPa)

Here's a phase diagram of CO2

So at such low pressures, CO2 is vapor at diurnal temperature ranges. My theory seems not to hold. Please go back to sleep.

Re:In the exalted words of our esteemed former VP.

[croddy]

qualye quotes (like gore quotes and bush2 quotes) are more often false. snopes does attribute this one to him though.