41
votes
Accepted
Could the Moon keep an atmosphere?
It can keep an atmosphere, and in fact does. The atmosphere is something akin to a high grade Earth-based vacuum. But that's probably not what you are looking for.
What would happen with an Earth ...
- 121k
23
votes
Accepted
Self-sustainable Hermetically Sealed System: Humans & Plants
This is being done with biosphere 2 and several similar projects and found to be very complicated. Specifically in a small sealed system there is little buffering or inertia available if one element ...
- 21.4k
22
votes
Place a satellite at Sun-Mars L1 to shield Mars from Sun radiation
This answers the question on how to block ions coming directly from the Sun from hitting Mars by a satellite stationed at L1. It does not cover the fact whether such a shield is effective in reducing ...
- 14.9k
21
votes
Accepted
Terraforming Mars using a combination of aerogel and GM microbes?
The underlying aerogel scheme seems to have some serious fundamental flaws:
Aerogel is extremely expensive, and you need enough to cover a significant portion of a planet.
Aerogel is extremely ...
- 10.7k
20
votes
What would be the effect of increasing the mass of Mars?
Planets are much, much bigger than you think.
The total mass of all the bodies in the main asteroid belt is about half of 1% of Mars's present mass. There's no realistic way to round up enough loose ...
- 167k
18
votes
Why not bring life to Venus along with the next exploring mission?
Question: Why not bring cyanobacteria and fertilizer to the atmosphere of Venus to improve conditions for life there by producing oxygen ?
... Only a few scientists have speculated that ...
- 3,256
17
votes
Is Mars' gravity strong enough to hold a human-breathable atmosphere?
Q: If we ever try to make Mars outdoors habitable, won't the air just keep flying off into the outer space because of low gravity?
Yes, but very, very slowly, so slowly, that it would not matter for ...
- 148k
16
votes
Accepted
If Mars had a denser atmosphere, how warm would it be?
Other factors being equal, planetary temperature (measured on an absolute scale e.g. degrees Kelvin) falls with the square root of distance from the sun, so a merely Earth-like atmosphere isn't enough ...
- 167k
16
votes
Accepted
What is stopping us from starting to terraform Mars right now?
A few of reasons for not mounting such a terraforming mission now are:
Cost-effectiveness. It's expensive to go to Mars, and simply throwing some seeds and fertilizer at the place is too unlikely to ...
- 17.4k
15
votes
Venus vs Mars for colonization
The reason Mars gets more attention than Venus is because we could walk on Mars. Our current technology can handle Mars. Venus on the other hand everything dissolves in a few hours from the heat and ...
- 1,020
15
votes
Accepted
How deep a valley or trench would be needed on Mars to provide the same atmospheric pressure as 6 km above sea level on Earth?
Mars' atmosphere scale height is, depending on who you ask, 10.8 to 11.1 km.
Pressure at the bottom of Hellas Planitia: 1.16 kPa
Earth sea level: 101.3 kPa
Earth 6km altitude: ~50 kPa.
So we need ...
- 167k
15
votes
Terraforming Mars using a combination of aerogel and GM microbes?
"Microbes that are genetically modified to produce perfluorocarbons" do not exist, for good reason.
Carbon is a useful building block for life not only because each atom can form 4 bonds, ...
- 47.8k
14
votes
Could the Moon keep an atmosphere?
PearsonArtPhoto covers the basic issue, which is that light molecules move so fast that they reach lunar escape velocity.
The average speed of the molecules of a particular gas is proportional to the ...
- 2,743
13
votes
Where's the Nitrogen on Venus?
There is nitrogen in the atmosphere of Venus, four times the amount of nitrogen on Earth. Because Venus' atmosphere is so dense, made up almost entirely of carbon dixode, the percentage of nitrogen ...
- 6,907
13
votes
Accepted
Harvesting Venus' atmosphere to Terraform Mars
There are easier ways to enhance Mars's atmospheric pressure, so no, don't use Venus materials. I calculated the energy required to lift a kg of nitrogen — or a kg of anything, for that matter — out ...
- 18.2k
12
votes
Is Mars' gravity strong enough to hold a human-breathable atmosphere?
Not for the long term, although it might last for a while. We can see what level of gas can stay based on the gravity and size of an object, as seen in the below chart from Wikipedia.
Bottom line, ...
- 121k
11
votes
Accepted
Will thinning the atmosphere of Venus make its surface habitable?
There's several advantages and disadvantages to Venus compared to Mars terraforming and colonization:
Advantages:
Venus's gravity is ~0.9 G which is very similar to Earth's
Venus is closer to the ...
- 18.1k
10
votes
Removing perchlorate from Mars surface soil
Perchlorate contamination is a problem on Earth. Essentially, there is a series of water treatments and bioremediation, the process of using biological systems to fix the problem.
Here is a detailed ...
- 2,253
10
votes
Harvesting Venus' atmosphere to Terraform Mars
No. Moving N2 or O2 wouldn't make sense, because it would require moving about a quadrillion tons from one planet to another, while we've barely figured out how to move one ton up from one gravity ...
- 11.5k
9
votes
Would it be possible to deploy a man-made magnetic field in Mars orbit for terraforming?
If you are able to terraform Mars in some reasonable amount of time, let's say in 100 years, then you don't need a magnetic field. Just do whatever you did to terraform the planet, but at one ...
- 58.5k
8
votes
How could an induced magnetosphere be created at Mars for terraforming?
The way to solve this problem has recently been proposed by NASA. Put a magnet on the L1 Legrange point (between Mars and the Sun) of about 2 Tesla. This is what it looks like:
At present, ...
- 383
8
votes
Accepted
Could we achieve aerodynamic and aerostatic lift on the Moon if it had an atmosphere of xenon?
First of all, while xenon would be the most stable due to its molecular weight being the largest of any elemental non-radioactive gas, there are other gases that would work as well. Sulfur ...
- 121k
8
votes
Is a magnetic field really needed to terraform Mars?
Mars has no magnetic field to protect any atmosphere we might add to the planet, but fortunately it would be lost very slowly, over geological time. Fortunately, both protecting and creating a Martian ...
8
votes
Venus vs Mars for colonization
Leaving aside the terraforming question, having a floating habitat is non trivial since pretty much the only thing that is earthlike at the proposed altitude is the temperature. The pressure is very ...
- 21.4k
8
votes
Accepted
If I wanted to try to terraform Mars, who would have the authority to stop me?
Who would have the authority to stop me?
The country from which you're trying to launch.
Article IX of the Outer Space Treaty (formally, the "Treaty on Principles Governing the Activities of ...
- 73.2k
8
votes
Removing perchlorate from Mars surface soil
Apart from perchlorate treatment mentioned in @Chris's answer, there are some other methods which could be able to remove the perchlorate from the martian soil:
Rinsing the soil with water. ...
- 1,015
8
votes
Using Venus' Atmosphere to Cool the Earth
While the earth's magnetic field was disturbed by the tests mentioned, I don't think there's any sign that the field as a whole was degraded, certainly not on a timescale that would materially affect ...
- 6,687
8
votes
Terraforming Mars using a combination of aerogel and GM microbes?
Leaving aside the question of whether this is desirable, I think the biggest issue is the availability of fluorine.
While Mars is estimated to have more fluorine than Earth, tracing that back to its ...
- 7,736
8
votes
Accepted
Would an increase of a planet's mass affect its trajectory?
Firstly, orbital trajectories don't really depend on the mass of the orbiting object as long as the body they orbit (in this case the Sun) doesn't move.
The force of gravity is:
$$F = G\frac{m_1 m_2}{...
7
votes
Is terraforming mars with only 4 nuclear bombs/penetrators in 10 years possible as this paper says?
I'm not an expert in any of the topics of the paper, but on a quick read I see it's full of naive assumptions about ratios -- to cover 1/20 the area requires 1/20 the energy release, 6% of cap ...
- 167k
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