how thick of an atmosphere could mars realistically have? can humans live in an ATM of 0.3?

Question

in terms of atmospheres. i mean, mars' gravity could only keep hold of so much atmospheric gas.

hmm. let's see. we can figure out the gravitational strength by looking up the acceleration due to gravity on mars, which is 3.69 m/s2 at the equator, as compared to 9.81 m/s2 for earth. so the gravity strength is about a third of earth's - does that mean mars can only support a third of earth's atmosphere? if it does, that means it can only support an atmospheric pressure of about 0.3 ATMs, which is pretty much nothing...can humans live in an environment of 0.3 atms?

turns out that venus has an atmospheric pressure 90 times that of earth so i think the gravity/atmosphere correlation is incorrect.

"A terrestrial planet, it is sometimes called Earth's "sister planet", as the two are similar in size and bulk composition. The planet is covered with an opaque layer of highly reflective clouds and its surface cannot be seen from space in visible light, making it a subject of great speculation until some of its secrets were revealed by planetary science in the 20th century. Venus has the densest atmosphere of the terrestrial planets, consisting mostly of carbon dioxide, and the atmospheric pressure at the planet's surface is 90 times that of the Earth."

Answer 1

That's like living above Mount Everest. No, it is not possible.

http://bmj.bmjjournals.com/content/vol317/issue7165/images/large/abcoxy5.f2.jpeg

Answer 2

This is a very interesting question. I once read an analysis of this very question, and it seems that Mars could hold an atmosphere of 2.0 Bar, or 2 atmospheres, indefinitely. Remember that each gas molecule acts like a tiny spacecraft, and obeys Newton's laws just like any other bit of matter. The Earth's escape velocity is ~25,000 miles per hour. The average gas molecule travels at ~760 miles per hour. This difference is more than enough to keep a very dense atmosphere stable indefinitely on Earth. The escape velocity from Mars is about 8,000 miles per hour, which is still more than sufficient to hold an atmosphere of at least one Bar indefinitely. Remember that the Earth once originally had a very Venus like CO2 atmosphere which has been estimated to be 60-100 atmospheres in density. Virtually all of this CO2 did not escape into space, but rather it became locked up in the regolith as carbonate rock. According to the analysis that I read, even the Moon could hold a 1.0 Bar atmosphere with a half life of of approximately one million years. While this is not considered "stable", It is certainly longer than my lifetime.
As to your question about could people live in a 0.3 Bar atmosphere, the answer is yes. The skylab space station had a 1/3 atmosphere pressure, with 60%O2 and 40% N2. The astronauts lived quite effectively and comfortably for several months in this atmosphere. Higher plants have been shown to be able to live quite well in only 1% of a Bar, with 80%O2 and 20%CO2. So adding only a small amount of O2 to the Martian atmosphere could allow farming and forests to proliferate across Mars, growing out in the open. Kind of neat, huh.

Answer 3

Rotational force has nothing to do with the density of the atmosphere where ever it is - it is a function of mass!! The more massive the planet and the more massive the components of the atmosphere will determine the atmosphere's density.As far as we currently know, humans would not be able to BREATHE the atmosphere on Mars because of the constituent elements of its atmosphere. However the density is a critical issue because the lower the density - the lower the boiling point of blood.

Answer 4

yes you could.
atmosphere needs to be no more than 1% CO2 and at least 17% Oxygen.
Without it our blood would boil.
Mars currently is 95% carbondioxide.

Answer 5

Nope.

We would slowly explode, as we need very close to 1 atmosphere.

William