
Most of Mars' air was 'lost to space' - daegloe
http://www.bbc.co.uk/news/science-environment-39459561
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tradersam
> That liquid water once stood on Mars' surface or flowed freely at times
> seems obvious.

> However, climate models, based on the limited evidence to date of what the
> atmosphere was like, have struggled to simulate a Mars on which conditions
> were warm enough to allow lots of liquid water. Much of it would have been
> locked up in ice, they suggest.

Bit contradictory here.

~~~
the_d00d
I disagree.

The section you are quoting is titled 'climate conundrum'.

The writer is saying that it is visually obvious that there was running water
at some point, but climate models do not support this.

That is why it is a .....conundrum.

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astro1138
What does that mean for terraforming? Establish a magnetosphere first so that
solar winds don't drag away an atmosphere?

~~~
theWatcher37
At humantimescales it's a non-issue. Any terraforming effort capable of
generating an atmosphere over ~100 years or so could more than compensate for
losses to space.

One great idea I heard to make mars more habitable in general is creating a
large magnetic field at a Lagrange point between mars and the sun. A sort of
"radiation sunshade"

~~~
M_Grey
It's important to realize that when it comes to terraforming you have a
tradeoff between speed and cost. The notion of producing an atmosphere in a
100 years is borderline magical, but certainly _staggeringly_ expensive in
terms of energy input. Your "sunshade" is another example of a quick, but
incredibly pricey option.

Most terraforming research tends to be more realistic, and therefore looks at
scales of thousands of years for change to take effect, often driven by
engineered single-celled organisms in stages.

~~~
dwaltrip
For those who are interested, I recommend the terraforming​ video by the
excellent Isaac Arthur:

[https://youtu.be/ikoNQNj9ZnU](https://youtu.be/ikoNQNj9ZnU)

I discovered his channel a few weeks ago, and was blown away. He has tons of
videos that cover all aspects of humanity's potential future in the stars in
great detail, and does a very good job of staying grounded in hard science. It
seems like he really knows his stuff. The episodes can be quite long (15 - 60
mins), but definitely worth checking out. I've been slowing making my way
through them.

~~~
M_Grey
I'm always looking for youtube channels like this, and that's right in the
timeframe I look for. Thanks!

~~~
dwaltrip
My pleasure. Some of the earlier videos from his megastructure series are a
little slow, but he has some absolute gems.

So far, I've really liked the video on "Black hole farming at the end of
civilization", some of his Fermi paradox episodes, as well as the one on
terraforming.

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spraak
Some of my friends cite 'sources' that humans came from Mars but destroyed the
planet's atmosphere and had to escape to Earth. They seem (slightly) less
crazy now!

~~~
ams6110
Yes they had the technology to travel to another planet but when they arrived
they threw it all away and lived in caves and hunted with rocks and sticks.

~~~
SandB0x
That's more or less what happens at the end of Battlestar Galactica (syfy
version).

~~~
Filligree
What ending?

That series never got renewed. It's a pity; the first season was nice. I'm
glad they didn't, though, because an ending like that would have made me
scream.

~~~
thom
Yes, this ranks up there with my disappointment that they never made Star Wars
episodes I-III.

