What you have just read is the brainchild of highly intelligent and highly qualified scientists. From here on, all you'll get is the hypothesising of a rank amateur ... me!!
I'm trying to extrapolate from the situation in Earth's region of the solar system, to that of Mars. And I've had to make a few assumptions along the way.
First of all, I've assumed that the number of snowballs in the space near Mars is roughly equal to the number around Earth. But Mars' mass, at 10% of Earth's, should mean only 1/10th the number of snowballs gets pulled in to hit the atmosphere. However, the surface area of Mars is only 28.3% that of Earth, so the rate at which water should accumulate on the surface is about 0.1/0.283, or 0.35 times the rate for Earth.
One inch every 20,000 years translates to 1 kilometre every 790 million years for Earth. This means a global layer of water for Mars of 1 kilometre every 2.26 billion years.
But of course this water should, if ambient temperatures allowed, accumulate in the low lying regions, which constitute about 40% of the surface (i.e. excluding the cratered southern highlands and the Tharsis Bulge). Thus, in the past 2.26 billion years alone, the last half of Mars' existence, enough water could have arrived to provide a northern ocean and Hellas Sea with an average depth of 2.5 kilometres!!
This completely ignores any water which Mars possessed originally, and which was outgassed through volcanism in the first 1-2 billion years when Mars' interior was hotter than today. And it also ignores the snowball comet influx during the first 2.26 billion years of the planet's existence.
Even if we assume that outgassing provided only a modest 1 kilometre depth of water in the lowland areas, the cometary water would add enough to provide up to 6 kilometres of water in those same areas over the whole of Martian history!!
Most authorities I've read about, seem to think that Mars still has most of the water it started out with. Some believe that impact blasts and atmospheric hydrodynamic escape are unlikely to cause much more than a 10% loss over geological time periods.
Even if we allow a very generous factor of, say, 1/3rd for losses, it would seem possible that Mars still has enough water in the polar caps and the regolith to fill the lowland areas to an average depth of about 4 kilometres!!
We still don't know for sure just how much water Odyssey detected in the regolith of the Martian southern hemisphere because the instrument operates only in the topmost metre of the 'soil'. And we have yet to hear the results of a similar survey of the northern plains because we're still supposed to be waiting for the CO2 to clear in the comparative warmth of the northern summer.
If this snowball comet theory is found to be accurate, I wouldn't mind betting that Mars has a surprise or two for us yet as far as water is concerned!!
I suspect that Mars is merely on a carbon dioxide global retransmission cycle. The atmosphere isn't really getting thicker. More and more is just moving to the north pole during the southern summer. Check out the latest CO2 snow depth on the northern residual cap.
It just gets deeper and deeper!
]]>I think that it would be a bit premature to say that just because Earth is warming and Mars is warming, there is a connection between the two - correlation and causation and all that. It does seem that greenhouse gases (mainly CO2) are the culprits in both cases though - but the circumstances are wildly different.
]]>"global warming" mars
on Google...
I was trying to find a particular MOLA article, but I couldn't. Mars' southern risidual ice cap is receeding a few meters a year, but it's my suspicion that Mars doesn't actually have enough carbon dioxide to sustain a warm atmosphere... it's all in the form of carbonate.
]]>Researchers have concluded the hydrogen detected is not distributed uniformly over the upper 3 feet (one-meter). Rather, it is much more concentrated in a lower layer beneath the top-most surface.
Boynton said that the amount of hydrogen detected indicates 20 to 50 percent ice by mass in the lower layer. Because rock has a greater density than ice, this amount is more than 50 percent water ice by volume.
Heating a full bucket of this ice-rich polar soil would yield more than half a bucket of water, Boynton said.
"There's really an awful lot of water that's in there when you melt it," he said
So - there's a lot of water. What I would like to know is what effect terraformation would have on the Martian landscape - if there's a lot of water around, could we be seeing some serious disruption of the surface? I certainly wouldn't want to be the one who's living on a base that sits on top of several metres of ice when the temperature goes up...
]]>Does anyone here remember a recent story about Mars warming up?
It was within the past few months, as I recall. I don't remember the amount of warming that had been measured. Earth is also warming. I think the two are connected. There's no SUVs running around on Mars causing global warming. At least as far as I know!
]]>Perhaps as Josh said Mars really did have a warm, wet past with a long-lived ocean; this would be quite conducive to the formation of life and we might find fossils. If there's a lot of water underground, it's not impossible that there is some liquid water about, so there might even be extant life. Personally I think that if either case were true, that's definitely 'something amazing'.
]]>In other words, there is more evidence now than ever to say that Mars was once warm. Once had a large ocean. And had this ocean for many millions of years.
That's basically what he means.
It's too early for anything else.
]]>Breaking the Surface: How Scientists Could Use Mars' Water-Ice
By Leonard David
Senior Space Writer
posted: 09:15 am ET
30 May 2002
On Mars, water ice may be both biological buried treasure and a rich resource for future Mars explorers.
NASA's 2001 Mars Odyssey spacecraft has found enormous quantities of subsurface water ice. Scientists using the spacecraft's gamma ray spectrometer instrument have detected hydrogen in the upper three feet (one-meter) of soil. That hydrogen is believed likely to be in the form of water ice.
The spacecraft spotted enough Mars water ice to fill Lake Michigan twice over in what may be a "splash" of data, with the deluge yet to come.
Odyssey scientists were ready to report their findings on Thursday at a NASA Space Science Update briefing in Washington, D.C. However, over eager reporters hijacked the announcement, breaking embargoed information, thereby forcing the space agency to cancel the briefing.
More than a month ago, one early science result from Odyssey was a tantalizing detection of frozen water on Mars, surrounding the planet's south pole. The signature of buried hydrogen has also been found in the north, but not in the areas close to the pole.
"What's important now is that we don't have use terms like 'gobs' and 'whopping huge' amounts of subsurface water ice," said William Boynton, principal investigator for Odyssey's gamma ray spectrometer suite at the University of Arizona, Tucson.
"I'd have to give the instrument an A-plus. It's doing everything we expected, and more so," Boynton told SPACE.com.
Researchers have concluded the hydrogen detected is not distributed uniformly over the upper 3 feet (one-meter). Rather, it is much more concentrated in a lower layer beneath the top-most surface.
Boynton said that the amount of hydrogen detected indicates 20 to 50 percent ice by mass in the lower layer. Because rock has a greater density than ice, this amount is more than 50 percent water ice by volume.
Heating a full bucket of this ice-rich polar soil would yield more than half a bucket of water, Boynton said.
"There's really an awful lot of water that's in there when you melt it," he said.
Priming the pump
Boynton said there's much more work needed before dispatching astronauts to the red planet. But knowing an ample supply of underground water ice exists on Mars ahead of time clearly primes the pump, so to speak, he said.
"There's enough water there that astronauts don't have to worry about bringing water along with them," Boynton said.
"All you have to do is heat it up and the water is going to run out. You just put it through a filter?nothing any more elaborate than the kind of filter you'd use on your coffee pot," Boynton said. "My guess is that it would be clean enough to drink right like that," he said.
Boynton added, however, that astronauts would have to be on their guard not to drink contaminated water. "If you melted the ice and you found too much bacteria?.well, actually that would be great news. It means you've got life on Mars," he said.
"They could always boil the water and not have to worry about bacteria. My guess is, based on everything we know at Mars is that water would be pretty pure, with no organic matter in it at all," Boynton said.
Designing a future Mars lander to dig down and sample the ice layer, heat it up, and measure its organic content would be a straightforward experiment, Boynton said. "Obviously, it would be very useful to bring some of this ice back to Earth labs and study it in detail," he said.
Climate story
Bruce Jakosky, an astrobiologist at the University of Colorado in Boulder, said the Odyssey data points to a climate story, rather than a biology tale. "The big thing is that the water ice detected in the regolith [the top layer of Mars] appears to be most consistent with it being deposited via vapor exchange with the atmosphere," he said.
Odyssey is "telling us more about climate and climate history than about biology, Jakosky said. "At present, there is no way to warm this water ice enough to get even trace amounts of liquid. The ice is in equilibrium with atmospheric vapor," he said.
Given Mars temperature, this is way below the melting point under any reasonable or realistic conditions, Jakosky said. The new Mars data is spelling out an important climate story, he said.
"It tells us about the atmospheric water cycle and, by implication, the polar water cycle and the history of climate over the last few hundred thousand or million years. It's one more very important piece of the puzzle that we are putting together on how water behaves on all time-scales and what the nature of the climate is," he said.
Unseen planet
"Mars never fails to surprise," said Jim Garvin, Mars Program Scientist at NASA Headquarters in Washington, D.C.
Odyssey's observations show the strength of NASA's Mars strategy of "follow the water," Garvin said. "Our 'science catch phrase' has proven amazingly resilient and has maintained its relevance. Finding gobs of hydrogen-bearing stuff, which Boynton and team are interpreting as water ice, in new places and at new concentrations?bolsters our approach," he said.
Garvin said that Odyssey also shows that as measurement perspectives on Mars change -- from imaging to the infrared and now neutrons and the like -- "we see yet more of the 'previously unseen' planet," he said.
Finding water ice in abundance today on Mars means that follow-up spacecraft are going to be busy.
For instance, a U.S.-Italian-built radar onboard the European Space Agency's Mars Express will look deep below Mars' surface. Mars Express is now being readied for a June 2003 liftoff.
In addition, NASA's Mars Reconnaissance Orbiter, to be rocketed toward the red planet in 2005, totes along a subsurface sounding radar to probe at shallow depths and a high-tech hyperspectral imager too.
Something amazing
"It's my own view that the Odyssey findings that Boynton and team have given us further strengthens the possibilities that Mars is hiding something amazing," Garvin said.
"I'll bet that we have not seen anything yet.... and just wait till those Mars Exploration Rovers start ambling around in early 2004," Garvin said.
Odyssey's revelations, Garvin said, will not alter NASA's step-by-step plan to explore Mars.
Garvin said that NASA's Mars Exploration Program strategy is both vindicated and re-affirmed with Odyssey's results. Moreover, the probe has much more to offer in months to come.
"Mars will not let us down," Garvin concluded.
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