View Full Version : Mars/ Earth co orbital--potential for future colony

2009-Jan-26, 04:06 PM
If Mars could be positioned say, 0.1 AU away from Earth, would it stay in its own orbit, or become trapped in Earth's orbit as a co-orbital? That is significantly less than the distance between Earth and Venus. (0.28 AU?)

How close COULD Mars be to Earth, theoretically, without terrible consequences?

OK, bear with me. We don't have the technology, but IF we could nudge Mars closer--perhaps with methods scientists are experimenting with to protect us from potentially dangerous asteroids--it could open up lots of possibilities.

IF Mars were orbiting closer to the sun, maybe it could better hold an atmosphere?
If Mars were closer, then it wouldn't take so long to travel there. (though at this point we'd have more advanced propulsion systems to get us there faster.)

I know, it's out of our present realm, but fun to think about.



2009-Jan-26, 04:57 PM
IF Mars were orbiting closer to the sun, maybe it could better hold an atmosphere?
I don't know about that. Why would it?

If Mars were closer, then it wouldn't take so long to travel there.

Still, I think it would be about a trillion times easier and more efficient for us to take the time to travel there as opposed to moving Mars closer.... :lol:

2009-Jan-26, 05:59 PM
Mars' thin atmosphere is primarily due to both it's low gravity as well as it's relatively low volcanic activity as compared to Earth.

Moving it towards the sun would only serve to sweep away more of it's fringes into space. I'm not sure what "lots of possibilities" that would open up. The Moon is a lot closer, with a much shallower gravity well and intense sunlight (solar power) half the time.

If I had an opportunity to become a Loonie, I would!

2009-Jan-26, 06:14 PM
Earth's magnetic field prevents the sun from blowing away its atmosphere. Mars, without a strong magnetic field, lost its atmosphere. Putting it closer to the sun would only make things worse unless you could create a magnetic field for it.

As a rough estimate, Mars could have an orbit as close as 0.03 AU from Earth and remain stable according to the formula on page 6 of http://arxiv.org/ftp/astro-ph/papers/0603/0603200.pdf . Here's an online calculator so you can play with the formula yourself: http://orbitsimulator.com/formulas/reachexterior.html . At opposition, Mars would appear as a disk.

If we had the technology to nudge Mars into a new orbit, we'd probably also have the technology to get there rapidly even at its current distance.

2009-Jan-26, 07:45 PM
I suspect that you would do better to move Venus outward, but the capacity to do any such thing would imply the deployment of technology that would make the modification of planetary surfaces either trivial or irrelevant.

2009-Jan-26, 08:08 PM
OK, sorry! Mars is too small, has no magnetic field, and poor plate tectonics. Forget Mars. Moving Venus to cool it down and get rid of that atmosphere may be better.

But you're right; if we could move planets, we would have amazing technology, hence great propulsion systems. So why not just go find an exoplanet that already is in an optimal orbit.
I'll need to go to another solar system to dream things up. (...I see that eye rolling out there)

Thank you for the article link and formula!


2009-Jan-26, 08:36 PM
It would be easier to leave Venus where it is and use some sort of huge sunshade to reduce/eliminate sunlight heating.

2009-Jan-27, 12:17 PM
OK, let's leave all our planets where they are. I am now going off into another solar system...


I feel very dense admitting this, but I could not find that constant in the formula you sent, tony873004. (grr.)

2009-Jan-27, 05:50 PM
Just use 3 for that constant if your orbits are round.

2009-Jan-28, 01:52 AM
I'm all for leaving them where they are too.... Sheesh who want even more neighbours...

2009-Jan-28, 07:19 AM
By the time we figure out how to do that, we would have already figured out how to make black holes, and probably destroy the Earth.

2009-Jan-28, 08:00 PM
Gee, that's a cheery thought...