It’s the solar wind that stripped Mars atmo once it’s core cooled and no longer was generating a large magnetic field to produce a magnetosphere....NASA has a plan to create a large plasma bubble and an artificial magnetosphere. Then Mars could hold an atmosphere it has the mass to hold one and did for a long time while it has the protection of its magnetosphere Mars once had a sense atmo, liquid oceans and was much warmer. It was conducive to life hundreds of millions of years before earth cooled enough to hold liquid water on its surface. It’s entirely possible life evolved there first and we know meteorites have come from Mars to Earth and landed in one piece with the internal temp of the inside not getting above a hundred F from the deep cold of space to touchdown the what pulse is fast and largely contained to the other layers of meteorites.
https://astrobiology.nasa.gov/news/how-to-give-mars-an-atmosphere-maybe/
Get the plasma bubble big enough and you deflect the solar wind in its shadow.
As I said, a domed atmosphere is about the only practical way to get an atmosphere of any kind. If you tried to trap an atmosphere, without a dome, it’d be like being near the top of Everest.
According to Grok.
Mars can hold an atmosphere, but its small size and low gravity make it difficult to retain a thick, Earth-like one. Here’s a concise explanation:
Gravity and Size: Mars has about 38% of Earth’s gravity due to its smaller mass (about 11% of Earth’s) and radius (roughly half Earth’s). Lower gravity means less ability to hold onto atmospheric gases, which can escape into space over time, especially lighter molecules like hydrogen.
Current Atmosphere: Mars has a thin atmosphere, primarily carbon dioxide (95.3%), with nitrogen (2.7%) and argon (1.6%). Its surface pressure is only about 0.6% of Earth’s (6 millibars vs. 1013 millibars), too low to support liquid water or human breathing without aid.
Historical Atmosphere: Evidence like ancient riverbeds and minerals suggests Mars once had a thicker atmosphere, possibly supporting liquid water 3-4 billion years ago. Its small size, lack of a strong magnetic field (unlike Earth’s, which deflects solar wind), and geological inactivity led to atmospheric loss over time. Solar wind stripped lighter gases, and the planet’s weak gravity couldn’t retain them.
Comparison: Larger planets like Earth or Venus have stronger gravity, helping retain denser atmospheres. Mars’ small size limits its ability to hold a substantial atmosphere without external intervention (e.g., terraforming).
Could Mars hold a thicker atmosphere if artificially replenished? Theoretically, yes, but maintaining it would require ongoing efforts due to its low gravity and solar wind exposure. If you’re curious about terraforming possibilities or specific atmospheric data, I can dig deeper or check for recent discussions on X or the web. Want to explore that?
Gravity could be simulated with exercise suits, but there is no way to give Mars a solid atmosphere without increasing it’s mass to give it the gravity to hold one.
The idea that Mars had its atmosphere stripped by the solar wind is based on the idea that Mars had one in the first place. There’s probably no reason to think that the magnetosphere has any bearing on it at all.
That said, even if it did, and we introduced a 78 percent N 22 percent O atmosphere, presumably using blobs of frozen gases from the outer solar system, the solar wind would still require millions of years to get rid of it, leaving plenty of leeway for artificial replenishment.
Regarding Venus, it has a very slow and retrograde axial rotation. If that probably could be mitigated by a carefully planned large impact (assuming the planet has a lumpy distribution of density, as Earth does https://freerepublic.com/tag/potsdamgravitypotato/index?tab=articles ), perhaps using a huge chunk of ice, sufficient to cover the surface with water to a depth of tens of miles, changing the direction of rotation while changing the location of its axis.
After some long period of time, the planet would be cooled sufficiently to seed its ocean with aquatic plant life from Earth. Probably need GMO extremophiles to clean up the atmospheric residues first. A couple of thousand years should do it. :^)