NASA's Maven Mission Solves the Mystery of Mars' Lost Atmosphere 120
StartsWithABang writes: If you came to the Solar System some 500 million years after its formation, you would've found two world with oceans of liquid water, continents and all the conditions we know of for life to begin thriving: Earth and Mars. But unlike our own world, Mars' organic history was cut short when it lost its atmosphere and became a barren, desert wasteland. While we had some pretty compelling theories as to how this happened, it was only with the advent of the Maven mission and its first science results that we discovered exactly how, how fast and when Mars lost its atmosphere. One cool discovery: aurorae appear diffuse and all over the entire night sky on Mars!
Summary missing information (Score:5, Informative)
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Try the NASA site, here:
http://lasp.colorado.edu/home/... [colorado.edu]
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Let me get this straight: the 8 page article with pictures and videos had more information than the 4 sentence summary?
The problem is precisely that it is not a summary, but a clickbait paragraph. The title mentions a mystery solved, but you get zero info about it by reading the non-summary.
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Re:Summary missing information (Score:4, Informative)
And the magnetic field stopped why?
Mars, being half the diameter of Earth, has a higher surface to volume ratio. Thus, it cooled faster. Presumably the liquid core froze, or at least, enough of it froze to stop the dynamo of molten metal that creates the magnetic field
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And yet Mercury has quite a magnetic field, especially for its size and Venus has none even though only 10% smaller then the Earth.
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Not sure about Venus, though. Maybe it has a smaller core than you'd expect for a planet its size? It's difficult to tell, since its atmosphere has a nasty habit of melting all our probes.
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I doubt that the heat from the Sun makes a difference, it's still cooler then Venus. The huge metal core, perhaps. There's also the question of how much radioactives are in the various planets cores.
Re: Summary missing information (Score:2)
I haven't looked at the numbers, but could tidal forces have a heating effect?
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Mercury is in resonance with the Sun (3:2) so tidal forces should be minor. The orbit is also fairly circular.
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What heats Io (and other Jovian and Saturnian satellites) is the change of forces on on the planet between those from Jupiter (Saturn) and the forces from the other satellites.
Tidal forces are generated by the steepness of the gravitational
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Thanks for the explanation.
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My apologies, seems that Mercury has the largest orbital eccentricity of the planets and therefore 17 times higher tides then the Earth. Still sounds like the magnetic field is caused by the extra large core which is probably still molten from formation.
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It does.
The surface temperature of Mercury is hot enough that e.g. lead is melting.
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Venus also has a surface temperature that will melt lead. From https://en.wikipedia.org/wiki/... [wikipedia.org]
Temperature of Mercury from the wiki,
I see someone marked me overrated for pointing this out.
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Mercury has a lower average because there's nothing holding heat in on the night side. It does, however, hold the record for the greatest temperature difference in the solar system, between the day and night halves.
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So our solar system rolled at least 4 times with the dice, and won only once.
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Once? Where?
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Actually judging by the amount of sulfur and potassium in the crust, it was not involved in a giant collision. leading theory is that during formation the solar wind drove away the lighter materials with another theory that it was so heated that it had a rock vapor atmosphere which the solar wind drove away.
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Bulk rocks have density between 2.5 and 3.1. With compression in the depths that ge
So How Long Do We Have? (Score:2)
So what is the calculation of when the Earth's core will freeze over or is there enough radioactivity to last until the Sun finally expands and consumes Earth?
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Well, if you consider the longest a species of life on Earth has existed (which is about 200 million years I think) against time time frames being given for cores cooling and atmospheres being stripped... "how long do *we* have?" is the wrong question.
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If you consider the AVERAGE lifespan of a species - we're already almost there.
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Re:Summary missing information (Score:5, Interesting)
meanwhile Venus without intrinsic magnetic field and closer to the sun has an atmosphere thicker than earth
Re:Summary missing information (Score:5, Informative)
Gravity. Venus has about 0.8 the mass of the Earth. Mars has about 0.1 of the mass. That's a big difference. Without that extra mass, Mars doesn't have the gravity to hold in the atmosphere, so the solar wind is strong enough to strip it away. On Venus, there's plenty of mass to generate gravity which keeps the atmosphere in place with more force than the solar wind has to strip it. On Earth, there's even more gravity plus a magnetic shield that negates the solar wind completely.
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Also, that thicker atmosphere's convection current generates an intense magentosheath that protects from solar winds. In a way, Venus's atmosphere is self-bootstrapped.
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Venus has a mass comparable to Earth's. Mars' mass is 1/10th Earth's. While it's nice to put hard numbers to it, the reason why Mars' atmosphere got blown away isn't hard to understand.
Re:Venus (Score:2)
Should We Colonize Venus Instead of Mars? [youtube.com]
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Trouble is getting there in the first place won't be.
It is far more difficult (and costs a LOT more energy) to send a rocket to the inner planets than to an outer planet. The reasons are a bit complicated for a slashdot post (it's about how much orbital velocity you need around the sun in a smaller orbit and then to get into planetary orbit you have to slow down by a lot more).
It's possible and we've sent probes to venus but they used a lot more fuel than the same size probe would need to Mars despite Mars
Re: Venus (Score:2)
But getting to low orbit for landing Mars needs 2.1 km/s while venus needs 3.3 km/s.
You looked at the transfer alone but a trip is more than one burn. You have to add them all up.
One thing I havent factored in is the increased possibility of aerobreaking around venus. Not sure how that changes the final scores.
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(They mention this in the video but it still seems important to state) Venus is much more inhabitable than Mars is. The biggest issue at the moment is the fact that Venus's surface temperature is above 450 C. We currently know how to make a planet warmer over time, but we don't know how to make a planet that much cooler for multiple reasons. Partially because of the fact that with a sulfuric atmosphere and that temperature it becomes very difficult to even get any machines there for colonization.
Also no
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Venus is actually a fairly interesting prospect for colonization. You obviously don't go down to the surface with its lead-melting temperatures. However, about 50km from the surface you have temperatures a bit above freezing, the atmospheric pressure of roughly one atmosphere, and gravity that's very near Earth's. It's about the most earth-like place in the solar system that's not on Earth itself. The atmosphere is mostly CO2, which is a dense gas, so a balloon filled with breathable air would float. Y
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But what's the point about the cost of sending people there? Apart from the first few colonists - a few thousand - they'll breed their own inhabitants. why would they want poor foreign immigrants from a polluted or nearly uninhabitable planet like Earth will be in the thousands of years that the project would take.
Or ... were people thinking of dreams about the future being a substitute for dealing with current problems?
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The summary is missing important information.
No it isn't. The summary is providing just enough information to force you to go to the site for the answer. Look at the author. He didn't miss anything, he calculated the required amount of clickbaitness.
The next question (Score:1)
Why did Mars lose its magnetic field? Anything to do with its core solidifying?
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Re: The next question (Score:2)
Mars didn't lose its magnetic field, it just misplaced it. it is around the Solar System somewhere, so watch where you step.
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Reminds me at "American Gods", where Odin is asked: "Where did you lose your eye?" and he answeres: "I did not lose my eye, I know exactly where it is."
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The Martians designed a technology to attempt to weaponise earthquakes. It backfired, and stopped the rotation of the core.
Re:The next question (Score:5, Interesting)
Mass too small, internal heat too low to generate a liquid iron core dynamo.
As TFA says though, we don't have to worry about that since if we put a good atmosphere on it by terraforming, it would last several million years.
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But what's the point in doing all the hard work to terraform Mars when there is nothing that can be done to stop this? The planet is dead unless we can increase the mass and magnetic fields, two things we don't have the science to do, nor will have in any remotely near timespan.
Any work we'd do to terraform would be throwaway.
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You're 100% correct. If we took the time and effort to put an Earth-like dense atmosphere it would be gradually stripped away... ...in about 100 million years.
I think if we could manage to terraform Mars, I think we could probably do some even more interesting things with the terraformed planet in 100 million years.
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Van Luen: " 'Cause I don't have to, there have been people there for 20 years and they never complained about any hostile organism"
Ripley: "What do you mean, what people?"
Van Luen: "Terraformers, planet engineers, they go in set up these big atmosphere processors to make the air breathable, takes decades, it's what we call a Shake and Bake colony."
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As TFA says though, we don't have to worry about that since if we put a good atmosphere on it by terraforming, it would last several million years.
Great idea. Where are you going to get the carbon from to replace all the CO2 that has blown away?
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Great idea. Where are you going to get the carbon from to replace all the CO2 that has blown away?
Send Al Gore there. I hear he produces enough CO2 for a small planet.
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That's about a kiloton of coal every four months to just replace the current carbon that's being lost. To actually make a dent in the planet's carbon supply, it would be necessary to add more than that. Good luck finding the fuel to transport that, and the people who would be happy to see so much carbon leave Earth.
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As I estimated here, delivering atmosphere at one Chelyabinsk (-size meteorite) an hour, it would take hundreds of thousands to a million or so years to deliver the atmosphere needed.
No sir. (Score:2)
You and me both know it was aliens what did that to Mars.
http://www.dailymail.co.uk/sci... [dailymail.co.uk]
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Oh, and Joseph built the pyramids to use for grain storage.
http://www.cbsnews.com/news/be... [cbsnews.com]
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You know, I'll bet there are numerous subject in which you don't know anything. Do you expect him to know how to fix his computers and setup a server too?
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There is no behind your back, punk, you could create an account and see the signature just like everyone else. But, since you seem to be incapible of doing that, here is the signature:
--
APK is a Troll, please ignore him. If he had anything to say, he'd have an account.
Also, why would I care if your crap hits Google? Do you think it matters how much insane shit posting show up? You are the one that is looking bad, not me, so it doesn't bother me one iota.
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Which of course will not stop him from weighing in on the subject.
What would it take to replace Mars's atmosphere? (Score:5, Interesting)
The article says it would last for a while if we could, so...back of the envelope with probably horribly wrong numbers. Martian atmospheric density at the surface is 0.020 kg/m^3, human survival limit is something like 0.6 kg/m^3, so we need to add 29x current martian atmosphere to be long-term human survivable without a mask (for children and older, babies would still need higher pressure). NASA puts current atmospheric mass at 2.5e16kg, so we need to add 7.25e17kg. If we wanted to accomplish that task over a thousand years, or roughly 3.15e10 seconds, we would need to produce about 2.30e7kg of atmosphere every second for the duration. (At that speed, the loss rate of Mars's atmosphere due to solar wind is absolutely negligible.)
Martian surface area is 1.44e14m^2, which means we'd need to pull ~5,000 kg of atmosphere out of every single square meter of the planet if we don't have some other source. I don't know what density or composition Martian rock is, but rock in general is about 2.5g/cm^3, or 2500kg/m^3. So you might need to dig several meters into the ground to get what you're after, and expend one hell of a lot of energy to crack the oxygen out of it, but it's not like you'd need to dig a whole mile down across the whole planet or anything.
Re:What would it take to replace Mars's atmosphere (Score:4, Insightful)
...new idea. If you already have the crazy tech necessary to do all that, just have your robots fabricate enclosed colony space instead. Mine, smelt, build roof. Yeah it's still ridiculous future technology, but if all you want is to make the place livable, it's a lot faster if you just make a bunch of buildings. Hell, in the amount of time it would take to crack all those atmospheric gases, you could have your crazy future robots just build an entire planet-covering roof for an enormous habitation space. It would take less work.
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"...it's a lot faster if you just make a bunch of buildings. "
Which could be partly earth-sheltered to reduce radiation.
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Or we relocate Callisto, as in arrange a collision between Mars and Callisto. If that isn't enough energy to remelt Mar's core, then add Mercury. Or probably bang Mercury and Mars together first, then drop in Callisto so you don't lose the water that makes up Callisto. That might get you a habitable planet once the crust hardens up again.
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Venus: too much atmosphere, too hot.
Mars: not enough atmosphere, too cold.
The answer is so simple even a hipster twat who paints himself blue and has a shaved head and a silly beard could work it out.
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Find a planet between them that has just the right amount of atmosphere and it neither too hot or cold?
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In short, we would need to capture a small fraction of the mass of one of the gas giants, and transport it to Mars. It would be interesting to see a proposal on how that could be done.
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Perhaps, but it is more likely that we will have our hands full just surviving global warming here on Earth caused by the collective will of humanity.
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Heat mars....perhaps covering it in dark dust at the polar caps, put some machines there to pump out CFCs...global warming will cause sublimation of dry ice into carbon dioxide, a green house gas...planet heats more, more is sublimated, etc...hopefully get a positive feedback cycle going...
Maybe comet/asteroid impacts if needed....
Reflectors positioned to focus sunlight...
Nuclear detonations....
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I believe the normal science fiction solution is throwing comets at it. The comets can add water and various gases (although ammonia and methane probably aren't what you want for a liveable atmosphere) along with various organics.
I'm not sure it would do us a lot of good, but it might give Mars a chance to develop life of its own, especially if seeded with simple life from Earth.
Honestly, If we're going that far, I'd say a better target is Venus. Venus has no water. One of the theories for why Venus lack
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We just need Schwarzenegger to go to Mars and find some alien artifacts to make the atmosphere breathable in about 30 seconds.
Two planets with water and air? (Score:4, Insightful)
Submission claims that for the first 1/2 billion years there were 2 planets with water and air. What about Venus?
Venus was also possibly inhabitable for the first part of its life, perhaps billions of years, until the Sun got warm enough to boil the Venusian oceans and created a runaway greenhouse affect.
Same thing is predicted for the Earth as the Sun continues to heat up (due to having a higher percentage of helium with time and therefore higher density) perhaps in as soon as 500 million years.
Nice pictures though (Score:1)
Well add more mass then (Score:1)
Elon Musk suggested nuking Mars to warm it up [youtube.com].
How about engineering controlled tiny asteroid collisions at the poles, replace the solar wind matter being stripped off.
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"Let's hope there is a fifth dimensional being because none of this will happen with current leadership."
Of course. It would take little people who are good at math, fearless about engineering and have a track record of long-term thinking. Oh, wait -
Come on, let's make it Buzzfeed-worthy (Score:5, Funny)
Scientists discover this one weird trick to remove a planet's atmosphere!
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...Which the Democrat kids can then mug them for. So the same income redistribution takes place with either party.