Water Flowed Recently on Mars 411
elfguygmail.com writes "According to to Space.com 'Small gullies on Mars were carved by water recently and would be prime locations to look for life, NASA scientists said today.' "
Fast, cheap, good: pick two.
Article Text (Score:5, Informative)
By Robert Roy Britt
Senior Science Writer
posted: 24 August 2005
07:57 pm ET
Small gullies on Mars were carved by water recently and would be prime locations to look for life, NASA scientists said today.
There have been many studies of Martian gullies that concluded water was involved. But most of the features are ancient, or if they seemed modern then there were questions about how the water could stay liquid long enough to do the carving.
Scientists know there is a lot of water ice on Mars, locked up at the poles and beneath the surface elsewhere.
Water is a key ingredient for life as we know it, and other scientists have speculated that life on Mars, if there is any, could lurk just beneath the surface where ice melts in pockets.
A closer look
The new study suggests water may still bubble to the surface of Mars now and then, flow for a short stretch, then boil away in the thin, cold air.
The conclusion is based on computer modeling of the atmosphere and how water would behave.
"The gullies may be sites of near-surface water on present-day Mars and should be considered as prime astrobiological target sites for future exploration," said Jennifer Heldmann, the lead researcher from NASA's Ames Research Center. "The gully sites may also be of prime importance for human exploration of Mars because they may represent locations of relatively near surface liquid water, which can be accessed by crews drilling on the red planet."
Any potential long-term human presence on Mars would require a water source, both for drinking and to be broken down into hydrogen as fuel for return flights.
The claim that water carved the gullies is based on the shape and size of features spotted by NASA's Mars Global Surveyor.
Short gullies
"If liquid water pops out onto Mars' surface, it can create short gullies about 550-yards (500-meters) long," Heldmann said in a statement. "We find that the short length of the gully features implies they did form under conditions similar to those on present-day Mars, with simultaneous freezing and rapid evaporation of nearly pure liquid water."
Some of the gullies taper off into very small debris fields or leave no debris at all. That implies the water rapidly froze or evaporated.
Given the low air pressure on Mars, water would boil in a flash, the researchers say, so it is doubtful that ice accumulates in the gullies.
The findings will be presented next month at a meeting of the American Astronomical Society's Division for Planetary Sciences in Cambridge, England.
Re:What about climate ? (Score:3, Informative)
Re:What about climate ? (Score:2, Informative)
So, based on that alone, no the climate would not sustains humans. On parts of Mars, the day-time temps can reach ~20C, but the night-time is still too cold for life. Also, the atmosphere is only ~0.1% oxygen, compared to ~21% on Earth, and ~95% carbon dioxide compared to Earth's So bottom line is... glass domes!
Re:Someone inform me? (Score:3, Informative)
Thin vs THIN (Score:3, Informative)
The Martian atmosphere is much thinner than earth's, even at the highest peaks. I think the air pressure at Mt Everest is about 20% of sealevel, while on Mars it is 0.1%.
I don't have the numbers here, but I assume the physical foundation for this story is that at that pressure, the boiling temperature is below the freezing temperature, so water really can't exist stably in fluid state.
Re:Someone inform me? (Score:2, Informative)
Re:Someone inform me? (Score:3, Informative)
Or, to think of it another way, the state of matter is a function of how much it gets pushed together. H20 is liquid until it has enough energy for the molecules moving around in it to push against the molecules of atmosphere and escape from the mass. When it loses that energy, it gets forced back together. Less air pressure means less stuff pushing in means less energy is needed to escape. It's not an entirely perfect mental picture, but it'll get you close.
Re:Move on NASA! (Score:5, Informative)
The "radiation" theory is interesting, but I find a much simpler theory quite sufficient: two dimensional boundary interfaces. Picture that, say, you have some organic molecule forming on top of a grain of quartz sand underwater. There are different forces acting on one side of the assembly site than the other. The side that forms next to the water will not be likely to form in the same shape as the side that forms near the quartz.
Boundary interfaces abound in the universe - almost every joint between grains in almost every rock, from the surfaces of those rocks, from organic deposits, to liquids and gasses. If a certain substrate acts as a catalyst for forming a given molecule, and the molecule is rarely formed otherwise, it's only natural to expect that chiral form to come into play. Once the more dominant form is incorporated into a lifeform, it is "locked in" - more of that form will be created to help the lifecycle, while the other form won't be renewed.
Re:Move on NASA! (Score:2, Informative)
Re:Move on NASA! (Score:2, Informative)
You're wrong. The very first chapter of the Quran starts with the words:
"Praise be to God, Lord of the Worlds"
Several places in the Quran, it is said that God repeats creation. And there are several indications that this world was not the first.
Re:Move on NASA! (Score:3, Informative)
Re:Someone inform me? (Score:3, Informative)
The boiling point of any liquid is a function of both pressure and temperature, a point which you yourself seemed to make later in your post. Check out this article on phase transitions [wikipedia.org] for more technical discussion. (For yet more info, follow the link in the article pertaining to critical points.)
It's entirely possible for three material phases (solid, liquid, gas) to exist simultaneously for a given substance if you have the right combination of temperature and pressure; this is called the triple point.
Re:Someone inform me? (Score:3, Informative)
Not sure where you're getting your numbers from, but that's almost certainly wrong. According to this article [wikipedia.org]:
So if the boiling point of water is 69 degrees Celsius at 260 millibars, it's most assuredly far lower at 10 millibars. Assuming that the surface pressure on Mars is 10 millibars (which is 1 kPa), you can calculate the boiling point there. There's a handy boiling point calculator [cam.ac.uk] to assist with this; for 1 kPa of atmospheric pressure, you get just above -11 degrees Celsius as the boiling point of water. (This temperature is well within the typical temperature swing for the planet Mars. You can find the temperature and atmospheric pressure ranges at this site [solarviews.com]; the temperature ranges from -140 C to 20 C, with the average at -63 C. Pressure varies from 6.8 mbar to 10.8 mbar.)
my religion would be confirmed by such a discovery (Score:3, Informative)
Re:Move on NASA! (Score:1, Informative)
Many theologians would point you to the fact the creation myth puts the creation of earth on the first day, and the creation of life on the third, while heavenly bodies aren't created before the fourth. Ergo, there is no life on them.
Then again, theologians have widely altered their long-standing literal interpretation of 1 Chronicles 16:30, Psalm 93:1, Psalm 96:10, Psalm 104:5 and Isaiah 45:18 - saying earth is unmoving, and the center of the universe - when confronted with the facts. So I fully expect that when aliens are found, theologians will promptly stop to see this contradicting scripture.
Re:Move on NASA! (Score:1, Informative)
Like here: http://scriptures.lds.org/moses/1 [lds.org]
verses 33 to the end
(sorry to be an anonymous coward but i'm too lazy to register)