Slashdot Mirror
NASA's Maven Mission Solves the Mystery of Mars' Lost Atmosphere
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!
The summary is missing important information. As TFA discusses, the primary issue was (as already strongly suspected) the loss of the magnetic field around Mars. With only a very weak magnetic field nothing protected the planet's atmosphere from the solar wind which blasted the atmosphere away over a time span probably in the hundreds of millions of years. This last result, the slow loss of the atmosphere is a genuinely novel and important discovery because as TFA discusses this makes it more plausible that if there was life on Mars that it would have had time to evolve to survive the gradually harsher environment. The research also suggests that Mars will become completely airless in around 2 billion years.
Scientists discover this one weird trick to remove a planet's atmosphere!
#DeleteChrome
The Martians designed a technology to attempt to weaponise earthquakes. It backfired, and stopped the rotation of the core.
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.
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.
...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.
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.
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.
https://en.wikipedia.org/wiki/Inverted_totalitarianism
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.
Confucius say, "Find worm in apple - bad. Find half a worm - worse."