Author Topic: Copycat Mars may have had huge ocean, scientists say  (Read 1987 times)

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Offline Rapunzel

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Copycat Mars may have had huge ocean, scientists say
« on: July 23, 2013, 07:01:32 am »
http://now.msn.com/mars-may-have-had-ocean-covering-a-third-of-its-surface-say-scientists?ocid=ansnowex


Copycat Mars may have had huge ocean, scientists say
16 hrs ago



Forget a measly river: Scientists think a massive ocean may have once covered up to a third of Mars. High-resolution images from NASA's Mars Reconnaissance Orbiter show ridgelike features that researchers say are inverted channels that look an awfully lot like patterns made by water flowing into a large body of water. "Scientists are finding a rich sedimentary record on Mars that is revealing its past environments, which include rain, flowing water, rivers, deltas and potentially oceans," says Mike Lamb of the California Institute of Technology. "Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun." So maybe global warming is an intergalactic thing. [Source]
�The time is now near at hand which must probably determine, whether Americans are to be, Freemen, or Slaves.� G Washington July 2, 1776

Offline Rapunzel

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #1 on: July 23, 2013, 07:06:47 am »
http://www.csmonitor.com/Science/2013/0722/Water-on-Mars-Ancient-Red-Planet-had-humongous-ocean-say-scientists.-video

Water on Mars? Ancient Red Planet had humongous ocean, say scientists. (+video)


http://www.youtube.com/watch?v=SH40TEUsv0Y

Water on Mars: Images from NASA's Mars Reconnaissance Orbiter suggests that billions of years ago, as much as a third of the Red Planet's surface could have been covered with liquid water.

By Mike Wall, SPACE.com / July 22, 2013

 Scientists have spotted more evidence that an enormous ocean on Mars covered much of the planet's surface billions of years ago.
 
A NASA satellite has picked up evidence that an ocean of water existed on Mars that may have covered a third of the planet.

The latest clues were found in photos from NASA's powerful Mars Reconnaissance Orbiter circling the planet. The images show what appears to be an ancient river delta, which may have emptied into a vast Martian ocean that inundated up to one-third of the Red Planet long ago, a new study reports.

"Scientists have long hypothesized that the northern lowlands of Mars are a dried-up ocean bottom, but no one yet has found the smoking gun," study co-author Mike Lamb, an assistant professor of geology at the California Institute of Technology (Caltech) in Pasadena, said in a statement. [Photos: The Search for Water on Mars]
 
The new study does not provide the long-sought smoking gun, researchers stressed, but it further bolsters the hypothesis.

The team studied high-resolution images of a slice of the northern lowlands snapped by the HiRise camera aboard NASA's Mars Reconnaissance Orbiter, which can distinguish features as small as 10 inches (25 centimeters) on the Red Planet's surface.

Specifically, the scientists looked at a 39-square-mile (100 square kilometers) area that's part of a larger region called Aeolis Dorsa, which lies about 620 miles [≈ greatest diameter of the dwarf planet, Ceres] (1,000 km) from Gale Crater. (NASA's Curiosity rover touched down inside Gale Crater last August, kicking off a planned two-year surface mission to assess Mars' past and present potential to host microbial life.)

The small section of Aeolis Dorsa features many ridges called inverted channels, which form in river bottoms over time when coarse material, such as gravel, is deposited by flowing water. Inverted channels can linger long after the rivers that created them have evaporated, helping researchers trace the past activity of liquid water on Mars.

HiRise images allowed the study team to do just that in the section of Aeolis Dorsa they examined. They found that the inverted channels spread out markedly and slope steeply downward near their end, just as streams here on Earth do when they approach and empty into the sea.

Ancient river deltas have been discovered on Mars before. But most of them have been spotted inside craters or other geologically bounded regions, providing evidence for lakes but not global oceans, researchers said.

    In Pictures Exploring Mars with Curiosity
 
The newfound delta is different.

"This is probably one of the most convincing pieces of evidence of a delta in an unconfined region — and a delta points to the existence of a large body of water in the northern hemisphere of Mars," lead author Roman DiBiase, a postdoctoral scholar at Caltech, said in a statement.

Just how big this body of water was remains an open question. It would at least have flooded all of Aeolis Dorsa, covering about 38,600 square miles [≈ Iceland] (100,000 square km), researchers said. And it might even be the long-hypothesized global ocean, which some scientists suspect covered a third of Mars.

It's possible that the Aeolis Dorsa delta was once confined by a crater or other feature that has since completely eroded. However, this interpretation implies that the Martian surface is more geologically active than scientists think, team members said.

The researchers plan to continue searching for signs of the potential ocean along its coastline, in an attempt to shed more light on the Red Planet's warmer and wetter past.

"In our work and that of others — including the Curiosity rover — scientists are finding a rich sedimentary record on Mars that is revealing its past environments, which include rain, flowing water, rivers, deltas and potentially oceans," Lamb said. "Both the ancient environments on Mars and the planet's sedimentary archive of these environments are turning out to be surprisingly Earth-like."

The study was published online in the July 12 issue of the Journal of Geophysical Research.
�The time is now near at hand which must probably determine, whether Americans are to be, Freemen, or Slaves.� G Washington July 2, 1776

Offline Relic

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #2 on: July 23, 2013, 01:28:08 pm »
Mars is fascinating to me. The stuff I've seen proposes that Mars developed an ecosphere early on. The problem with Mars now, and why terraforming isn't likely is that Mars has no magnetic field. The core of the planet seems to have cooled, likely due to it's smaller size. No magnetic field, no shield from the sun's radiation means no complex life.

Oceander

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #3 on: July 25, 2013, 02:24:32 am »
Mars is fascinating to me. The stuff I've seen proposes that Mars developed an ecosphere early on. The problem with Mars now, and why terraforming isn't likely is that Mars has no magnetic field. The core of the planet seems to have cooled, likely due to it's smaller size. No magnetic field, no shield from the sun's radiation means no complex life.

Is Venus any more terraformable?

Offline Relic

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #4 on: July 25, 2013, 01:37:30 pm »
Is Venus any more terraformable?

I don't think so. The atmosphere is dense, with a large component of sulfuric acid and it's hot. Like 400 degrees hot. There may be life, but nothing we'd recognize.

Oceander

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #5 on: July 26, 2013, 02:17:47 am »
I don't think so. The atmosphere is dense, with a large component of sulfuric acid and it's hot. Like 400 degrees hot. There may be life, but nothing we'd recognize.

True enough, but terraforming necessarily implies making vast changes in a planet's global climatology, which I would assume includes making changes to the composition of the planet's atmosphere.

Offline Relic

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #6 on: July 26, 2013, 04:10:11 am »
True enough, but terraforming necessarily implies making vast changes in a planet's global climatology, which I would assume includes making changes to the composition of the planet's atmosphere.

Right, but in the case of Mars, given the existence of water/ice, it would be fairly easy. The problem is, no magnetic shield. I guess it one could be generated locally, but not on a big enough scale to make terraforming practical.

In the case of Venus, I'm unaware of a technology to thin out the atmosphere and change the chemical composition.

Oceander

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Re: Copycat Mars may have had huge ocean, scientists say
« Reply #7 on: July 29, 2013, 05:42:02 am »
Right, but in the case of Mars, given the existence of water/ice, it would be fairly easy. The problem is, no magnetic shield. I guess it one could be generated locally, but not on a big enough scale to make terraforming practical.

In the case of Venus, I'm unaware of a technology to thin out the atmosphere and change the chemical composition.

What about orbiting shields that significantly reduce the amount of sunlight reaching the planet?  That should reduce the overall temperature of the planet, thereby allowing some of the material in the atmosphere to condense and form oceans of some sort.  If Earth didn't have its oceans, the atmospheric pressure down at the "bottom" would be substantially higher than it is at the "bottom" now.

The chemical composition could be changed by either (a) liberating desirable compounds from the existing lithosphere, or locking undesirables in, or (b) dropping in meteors and/or comets containing desireable compounds.  In fact, if I recall, Venus has a dearth of water - although I don't know if it has a corresponding dearth of oxygen- and hydrogen- based compounds other than water - and so dropping a few comets onto the planet might be one way of changing the composition of the atmosphere by bringing more water to it.  I think there might also be issues with Venus' magnetic system as well.