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  (Source: Warner Bros.)
Mars had materials rich in oxygen about 4 billion years ago

A new study suggests that Mars had an oxygen-rich environment long ago -- even before Earth. 

Oxford University researchers, led by Professor Bernard Wood of Oxford University's Department of Earth Sciences, compared meteorites and surface rocks before coming to this conclusion. 

The team studied meteorites from Mars and rocks found by NASA's Spirit rover on Mars' surface. They found that the surface rocks were five times richer in nickel than the meteorites. 

They believe this is the case because of subduction, where material is recycled into the planet's interior. The study says that Mars' surface was oxidized long ago, and through subduction, materials rich in oxygen went into the planet's interior and were recycled back to the surface about 4000 million years ago. Earth didn't experience a rise in atmospheric oxygen until 2500 million years ago. 

The meteorites, though, are younger rocks that came from deep within the red planet. Hence, they are unphased by this subduction. 

"What we have shown is that both meteorites and surface volcanic rocks are consistent with similar origins in the deep interior of Mars but that the surface rocks come from a more oxygen-rich environment, probably caused by recycling of oxygen-rich materials into the interior," said Wood. "This result is surprising because while the meteorites are geologically 'young', around 180 million to 1400 million years old, the Spirit rover was analysing a very old part of Mars, more than 3700 million years old."

Spirit, a golf cart-sized, solar-powered robot geologist that was sent to Mars in 2004, spent six long years traveling the Martian surface. But after enduring many harsh winters on Mars, Spirit finally fell silent in 2010, and was removed from the mission in mid-2011. 

NASA has been relying on rover Curiosity to dig up new info on the red planet now. It landed on Mars in August 2012, and has found rock samples that suggest life on Mars and questionable radiation levels that could determine human travel to Mars. 

Source: Science Daily



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By BRB29 on 6/21/2013 12:27:59 AM , Rating: 3
Mars has a thin atmosphere because it lost its magnetosphere about 4 billion years ago. This allows the solar wind to strip air atoms away from it.

There are moons with thick atmospheres so it is not gravity. I would say gravity does play a role but a small one.


By ShieTar on 6/21/2013 5:46:28 AM , Rating: 5
It's a little more complex than that. Titan is the only moon with any relevant atmosphere in our solar system, and the reason why it exists is actually not very clear yet. It is widely agreed though that it needs to be replenishing by a release of gas from the moons interior or from external sources.
It is clearly not stabilized by the very low gravity of 0.14g, as this only requires an escape velocity of 2.6 km/s. A Nitrogen-2 molecule can reach this velocity after absorbing a single photon of a wavelength of 1.3┬Ám or shorter, which is the majority of the solar spectrum. As a comparison the escape velocity of earth is 11.2 km/s, so Nitrogen-2 needs to absorb a photon with a wavelength of less than 70nm, which is only a negligible part of the solar spectrum.


By drewsup on 6/21/2013 7:14:53 AM , Rating: 2
An interesting experiment for terraforming would be to send out a bunch of cheap small mass drivers to nudge asteroids into a low speed collision with Diemos,( Phobos is a lost cause, it's orbit is decaying fast). One would hope that if enough mass is added to Diemos, the core of Mars would unlock due to tidal stress induced heat. Maybe Mars could be habitable with a magnetosphere.


By BRB29 on 6/21/2013 9:21:29 AM , Rating: 2
That is a long shot. The amount of energy and time it would require. We humans are not known to be patient.


By wasteoid on 6/21/2013 11:04:49 PM , Rating: 2
Speak for yourself. I could easily wait *years* for Mars to be terraformed into a habitable pleasure destination.


By BRB29 on 6/24/2013 8:35:32 AM , Rating: 2
it would take more than years lol. It would take lifetimes and many many obstacles.


By delphinus100 on 6/23/2013 1:33:29 AM , Rating: 2
quote:
One would hope that if enough mass is added to Deimos, the core of Mars would unlock due to tidal stress induced heat. Maybe Mars could be habitable with a magnetosphere.


First, you'd need to make it seriously more massive to have any meaningful effect. Even Deimos and Phobos combined aren't enough to do anything.

Second, It's mostly a matter of primordial heat, and radiodecay of unstable elements in its mass, not 'tidal stress.' A larger sphere is going to lose less heat through its surface area, average density and all other things being equal, than a smaller one. Mars simply cooled off faster, Earth's moon faster still. Eventually Earth will become geologically dead, too. But not anytime soon. (IIRC. the Magellan orbiter may have detected current volcanic activity on the slightly less massive, slow rotating, moonless Venus.)


By delphinus100 on 6/23/2013 1:22:39 AM , Rating: 2
quote:
There are moons with thick atmospheres so it is not gravity. I would say gravity does play a role but a small one.


How well a planet (or other body) can hold an atmosphere is a function of gravity, the molecular weight of the gases in question, and the speed of those molecules (temperature) at the 'top' of its atmosphere.

Titan, Saturn's largest moon, can hold a substantial atmosphere in spite of being much less massive than Mars because it's mostly fairly heavy methane and nitrogen molecules, and because it's cold way out there. The chances are small that any of those heavy molecules will be kicked up to escape velocity. If you brought it closer to the Sun, that would go away fairly quickly.

The gas giant planets, however, are massive enough to hang onto light hydrogen molecules. The extrasolar 'hot Jupiters' we know to be out there are likely massive enough to keep significantly hydrogen atmospheres, even though within spitting distance of their stars.

Venus is pretty hot, has no real magnetic field either, but is massive enough to hang onto its mostly CO2 atmosphere, in spite of also being even closer to the source of the solar wind.

It's no surprise that colder but lighter Mars retains heavy carbon dioxide molecules as well.

It's not all about planetary magnetic fields and solar winds...


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