November 17, 2012
Wandering Planets Common In Space?
Some astronomers think they've found a planet unattached to a star wandering thru space 100 light years from Earth.
Astronomers using ESO's Very Large Telescope and the Canada-France-Hawaii Telescope have identified a body that is very probably a planet wandering through space without a parent star. This is the most exciting free-floating planet candidate so far and the closest such object to the Solar System at a distance of about 100 light-years. Its comparative proximity, and the absence of a bright star very close to it, has allowed the team to study its atmosphere in great detail. This object also gives astronomers a preview of the exoplanets that future instruments aim to image around stars other than the Sun.
Such worlds might be common.
These worlds could be common -- perhaps as numerous as normal stars . If CFBDSIR2149 is not associated with the AB Doradus Moving Group it is trickier to be sure of its nature and properties, and it may instead be characterised as a small brown dwarf. Both scenarios represent important questions about how planets and stars form and behave.
What I wonder: Do any space-faring species use these planets as stopping places to get materials during long voyages between solar systems that have intelligent life? I'm reminded by Niven and Benford's new novel Bowl Of Heaven about the need to get resupply for propulsion and food during long interstellar voyages.
So how could a spaceship remove materials from such a planet? It might be several times the mass of Jupiter and also a few hundred degrees celsius.
Randall Parker, 2012 November 17 09:47 PM
Why spend the fuel, energy and time to decelerate at a rogue planet to "refuel" instead of coasting to the target star and then decelerate?
Or perhaps it is a sleeper ship or a generation ship. Or just a rock, but it would seem a planet-sized object would normally form in a solar system. One scifi author (sorry, don't remember who,) based a story around the idea that Phobos, the Martian moon, which has an unusual albedo, very low orbit and unusual surface features, was actually a very old generation ship. it made a good story.
It makes sense for ships on our oceans to stop to resupply, because the kinetic energy getting up to speed is utterly dwarfed by energy expended against drag. As you suggest, there's no point at all in stopping along the way for a starship.
Except for two circumstances:
1. To resupply the life support system with volatiles. But an extra supply of volatiles would seem to be easier to store than the fuel involved. Perhaps only a factor if some accident enroute destroyed supplies.
2. As an intermediate destination, where people could actually colonize, and the next generation resumes the trip.
Some kinds of rogue planets might be suitable for colonization. This would depend on how accessible the heavier elements were. If they were all buried in the core, you'd be in trouble. If there were an accessible solid surface, or rocky moons, it might be feasible. Living on the moon of a rogue planet would certainly be isolated, but political and/or religious minorities might find that attractive. Nobody is likely to show up and interfere with whatever you're up to.