Mars may be emerging from an ice age, according to a new study | Hacker News Reader

Mars may be emerging from an ice age, according to a new study

theverge.com

122 pointsjonbaer67 comments

Following this story for the last couple days, it's interesting to see that based on the same research, the headlines have become more and more certain of the results. What started as "Mars may be emerging from an ice age..." has quickly morphed into "Mars is emerging from an ice age..."

Like this http://www.phdcomics.com/comics/archive.php?comicid=1174

It's classic herding behavior; that being earlier adopters are more willing to take risks in their view of reality, but also pragmatic in their observations.

The mainstream takes less risk and constructs a reality based on absolutes.

Laggers believe their reality is the only true one; when confronted with a reality that does not match their own, they ignore it until it's no longer an option to do so.

That's interesting, and of course ice ages have probably helped Mars retain more of its water than it otherwise would have, since it doesn't have a strong and protective magnetosphere.

How amazing would it be if this triggered runaway global warming and Mars terraformed itself?

But even just a few degrees warmer might still be very interesting.

Without an atmosphere, would be hard to start a greenhouse effect on Mars. [1] Carbon dioxide, as well as methane, have been long detected, but you need large amounts of these gases.

[1] https://en.wikipedia.org/wiki/Mars#Atmosphere

I counter your link with this one:

https://en.m.wikipedia.org/wiki/Terraforming_of_Mars

There is presently enough carbon dioxide (CO2) as dry ice in the Martian south pole and absorbed by regolith (soil) on Mars that, if sublimated to gas by a climate warming of only a few degrees, would increase the atmospheric pressure to 30 kilopascals (0.30 atm),[26][not in citation given] comparable to the altitude of the peak of Mount Everest, where the atmospheric pressure is 33.7 kilopascals (0.333 atm). Although this would not be breathable by humans, it is above the Armstrong limit and would eliminate the present need for pressure suits

For how long? Won't the lack of a global magnetosphere on Mars make that a relatively short term "fix"?

For hundreds of millions of years if not billions. It takes a long time for the solar wind to push that amount of gas away from a place with gravity even in the absence of a magnetic field.

The rate a lack of magnetosphere causes your atmosphere to be stripped away is in the order of hundreds of millions years.

This is a chicken-egg problem: in order to heat Mars you need greenhouse gases in atmosphere; you can only get that gases in atmosphere by heating Mars.

The only situation were this wouldn't be an issue is if the Sun is increasing the activity/power output so that the energy inputs the Mars system from outside. Then Mars would heat and the process would start.

But without active vulcanism or tectonics or mangnetic core, Mars would not heat by itself.

Terraforming by droping bacteria on Mars that would start releasing the gases faster is an option, but only when we are 100% there is absolutely no life on Mars as of now. We don't have yet this proof and therefore this solution is portponed until then.

But this whole thread is about Mars becoming warmer on its own because it's exiting an ice age. That's the chicken to your egg right there.

Would the energy from the impact of a big asteroid be enough to heat up Mars to that point? If so, maybe we could try to change the course of such asteroid to make that happen :)

It's my understanding that Mars doesn't have a magnetosphere to speak of, which significantly contributes to the lack of atmosphere on the planet.

How would a would-be terraformer address that?

I'd like to see Venus go towards an Ice Age, which might bring down the surface temperatures from average 462 degrees Celsius to Earth norms, and then maybe the place could be relatively habitable, albeit still with 96% CO2 and clouds of sulphuric acid to deal with.

The atmosphere of Venus, for what it is worth, is one of the most Earth-like places in the solar system. Breathable air is a lifting gas in the thick Venerian atmosphere, making floating habitats viable. Furthermore, at the altitude where the pressure is 1 atm and a habitat would stabilize (around 50km), ambient temperature is also in the range for liquid water. And even at this height, there would still be enough atmosphere left to provide protection from cosmic radiation.

https://en.wikipedia.org/wiki/Colonization_of_Venus#Aerostat...

The atmosphere also contains high levels of sulfuric acid which would be a bit of a concern. It's definitely a route worth exploring. It just comes with it's own set of crazy concerns.

Iirc, most of the H2SO4 haze falls below the habitable altitude, however there are clouds of it at that height. Biggest challenge would be the lack of water. You'd have to extract hydrogen from the acid to make water.

Yup. Problem with Venus is just that the ground is too far down.

The insane air-pressure ruins it. Basically, the solution to terraforming Venus is to convert the CO2 into water. The problem is that this requires hydrogen that's not readily available to do it. A lot of it.

How much?

At 1 Earth atmosphere, imagine a balloon filled with Hydrogen the size of the planet Mars. It would take two of those.

But then you could scrape enough CO2 out of the atmosphere to make oceans and Earth pressure.

A few years ago I read a paper that suggested freezing the CO2 out of the atmosphere, covering it with a layer of thermally-insulating material, and then putting oceans of liquid water on top of it to keep it sequestered. [0]

[0] - http://www.orionsarm.com/fm_store/TerraformingVenusQuickly.p...

Is that a good long-term solution? Can the CO2 just be left there forever?

The long term solution (per the paper) is to harvest the CO2. The paper states the CO2 will melt over time, but not as quickly as it can be harvested, and that water may even be poured in to melt it faster.

But who on Earth is so fond of CO2? right, plants via photosyntesis.

So why not sending green algae on Venus to harvest that CO2? When the temp drops, send something else, like trees.

Quite SF, but would worth a calculation.

If you want plants to do it, you need water, and there isn't any. The solar wind blew it all away.

Not just because "plants need water", because the chemistry is CO2 + H20 => O2 + carbohydrate

Indeed, you are right. Interesing link on this subject [1], it explains a bit more in detail the greenhouse runway process.

[1] http://www.vanderbilt.edu/AnS/physics/astrocourses/AST101/re...

Plants can't photosynthesize without water. No hydrogen, no water, no photosynthesis to take CO2 out of the atmosphere.

I would have thought you'd do it by making limestone. You just need lots of calcium for that.

`emerging` from something that `ended 400,000 years ago`. right.

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