“Dark matter could make planets habitable” (New Scientist, 30 March 2011), Maggie McKee tells us:
No one knows what dark matter is – astronomers merely detect its gravitational pull on normal matter, which it seems to outweigh by a factor of five to one. But many researchers believe it is made of particles called WIMPs, which interact only weakly with normal matter but annihilate on contact with each other, creating a spray of energetic particles.[ … ]
But closer to the centre of the galaxy, the concentration of dark matter is much higher – so this heating could approach the heat that Earth receives from sunlight. The researchers found that a planet weighing a few times the mass of the Earth, lying within about 30 light years from the galactic centre, could be heated enough by dark matter alone to maintain liquid water on its surface.
That would mean that any planets that had broken away from their host stars in gravitational tussles with neighbours could be habitable, even though they were floating through cold space.
And the heating would continue for trillions of years, since dark matter would continually be captured by the planets’ gravity. “This is the ultimate form of sustainable energy,” Hooper told New Scientist.
Well, it is the ultimate form of something, anyway … Friend Rob Sheldon responds,
Yeesh.The things people will propose just to get funding. (NASA has a big chunk assigned to “dark matter detection”.)
If you don’t know what dark matter is, then how do you know it will produce a megawatt?
And if dark matter could warm a small planet, think of what it could do for a neutron star? Now that would be observable.… Since we don’t know what dark matter is, how about assuming it is little balls of bacteria, and then we can solve OOL and the dark matter problem at the same time! That ought to double your funding options.
Now if only we could also assume it also possesses Dark Energy…
Actually, while we are in this space, we can assume just about anything. It’s the ultimate fun at work: science fiction for which one can get research grants.