May be an interesting place to send a space probe some day

choff · Post by **choff** » Thu Jul 28, 2011 8:50 pm

http://news.ca.msn.com/top-stories/eart ... -companion

rjaypeters · Post by **rjaypeters** » Sat Jul 30, 2011 3:58 pm

I have conjectured when humanity gets ready for planetary-scale engineering it might be useful to relocated Mars and Venus to Earth's Trojan points. Then I remember the orbits may not be stable...Has anyone done the math?

Anyway, it's nice to see at least one Trojan point has moons waiting for the new tenant.

Skipjack · Post by **Skipjack** » Sat Jul 30, 2011 5:59 pm

Yeah an advanced civilization in my favorite scifi novel series relocated two other planets to the orbit of their home planet.

Helius · Post by **Helius** » Sat Jul 30, 2011 7:51 pm

rjaypeters wrote:I have conjectured when humanity gets ready for planetary-scale engineering it might be useful to relocated Mars and Venus to Earth's Trojan points. Then I remember the orbits may not be stable...Has anyone done the math?

Anyway, it's nice to see at least one Trojan point has moons waiting for the new tenant.

Were it stable, there'd be crap in there already. It'd take constant energy to keep an object there, much like balancing a broom handle on your finger.

rjaypeters · Post by **rjaypeters** » Sun Jul 31, 2011 12:43 am

There is crap there already (at least around one) and the scientists hope the asteroid has been there a long time. So it can it be that difficult to, at least, orbit the exact Lagrangian points?

Specifically, does putting a large mass, Mars- or Venus-sized, near the Lagrangian points change the orbital mechanics enough from the Lagrangian ideal (one large mass, one smaller mass and one much smaller mass) that the Lagrangian orbits no longer exist?

Jonathan Burns · Post by **Jonathan Burns** » Sun Jul 31, 2011 1:25 am

rjaypeters wrote:I have conjectured when humanity gets ready for planetary-scale engineering it might be useful to relocated Mars and Venus to Earth's Trojan points. Then I remember the orbits may not be stable...Has anyone done the math?

Terrible idea!

Theorists in the Origin of the Moon debate consider it plausible that two planets accreted in our orbit: a supersized pre-Earth and another perhaps Mars-sized in one of the stable Trojan positions. When the latter grew too large it destabilized its own gravitational perch and wandered along the common orbit until finally it fell into pre-Earth's gravity well. After that, collision was just a matter of time.

But that still leaves room for us to place an awful lot of habitable stuff in our Trojans and inner-planet orbits in general. Just not whole planets.

kurt9 · Post by **kurt9** » Sun Jul 31, 2011 5:09 am

The more NEA's there are, the more resources to build O'neill style space colonies, whenever they come into vogue.

rjaypeters · Post by **rjaypeters** » Sun Jul 31, 2011 10:24 am

Jonathan Burns wrote:Theorists in the Origin of the Moon debate consider it plausible that two planets accreted in our orbit: a supersized pre-Earth and another perhaps Mars-sized in one of the stable Trojan positions. When the latter grew too large it destabilized its own gravitational perch and wandered along the common orbit...

Yikes!

Which leaves us with the question: How big a Lagrangian companion is too big?

Luzr · Post by **Luzr** » Sun Jul 31, 2011 11:55 am

kurt9 wrote:The more NEA's there are, the more resources to build O'neill style space colonies, whenever they come into vogue.

Exactly! I still do not quite understand why everybody is so dedicated about colonizing planets...

Betruger · Post by **Betruger** » Sun Jul 31, 2011 12:31 pm

Familiarity. It's gonna be a while before people don't get the munchies, so to speak, for earth under your feet and green fields and blue skies.

ladajo · Post by **ladajo** » Sun Jul 31, 2011 1:17 pm

Deep Space Radiation...

Betruger · Post by **Betruger** » Sun Jul 31, 2011 1:47 pm

And... So far there really aren't any planet sized bodies with Earth like atmosphere/magnetosphere. Indoor/underground radiation-shielding volumes that are large enough to feed that instinctive need for open spaces are far enough in the future that it's nowhere near being a consideration in most people's minds.

Helius · Post by **Helius** » Sun Jul 31, 2011 2:14 pm

Betruger wrote:And... So far there really aren't any planet sized bodies with Earth like atmosphere/magnetosphere. Indoor/underground radiation-shielding volumes that are large enough to feed that instinctive need for open spaces are far enough in the future that it's nowhere near being a consideration in most people's minds.

I'm thinking something like 8 cubic mile underground amphitheaters on the moon, with half mile high ceilings would be more than adequate. Wouldn't it be fun to fly to your favorite catch and release trout stream via a human powered hang glider?

kurt9 · Post by **kurt9** » Sun Jul 31, 2011 5:31 pm

Luzr wrote:
kurt9 wrote:The more NEA's there are, the more resources to build O'neill style space colonies, whenever they come into vogue.
Exactly! I still do not quite understand why everybody is so dedicated about colonizing planets...

Planetary chauvinism. Planets have romantic appeal. Since we live on a planet, the assumption is that we must always live on planets. Planets are nice if you can find habitable planets with warm oceans, beaches, etc. The problem is that there are no others like this in our solar system and the recent Keplar findings suggest that only 1 out of every 50-100 G stars has such a planet. Even if we get the warp drive, finding such planets will be like finding a flee on an elephant's ass.

Skipjack · Post by **Skipjack** » Sun Jul 31, 2011 5:48 pm

Exactly! I still do not quite understand why everybody is so dedicated about colonizing planets...

Well, of course our solar system has an expiration date and before that even we could be hit by a gamma ray burst or some other cosmic catastrophy that can not be prevented. In all these cases mankinds only chance of survival is if it has already colonized a planet, or multiple planets in another solar system.
So if we want to insure a long term survival of mankind, we have to expand to other solar systems or better other solar systems.
The survival of the human species should always be the highest goal.