A team of astronomers proposes that extrasolar planets wandering through space may not be the frozen wastelands experts first thought they were. Interactions between these bodies and dark matter could keep them relatively warm.
The investigation is focused exclusively on planets that have been kicked out of their star systems, and are now drifting through empty space at great speed. Such objects travel entirely on their own, in a straight line, and are only influenced by prevailing gravitational forces at each point in space.
This means that it could be drawn into orbit around a black hole, or a large star, if it's fortunate enough to come by such an object. Otherwise, it will continue on its cosmic path without ever slowing down.
Astronomers believed that temperatures on these worlds would be extremely low, due to the fact that only minimal amounts of photons would make their way to the surface to keep it warm. But a new study indicates that that may not be the case.
What researchers are suggesting is that weakly-interacting massive particles (WIMP), the stuff believed to make up dark matter, are producing heat when they are attracted by the gravitational pull of exoplanets. Dark matter is thought to permeate the Universe, accounting for 23 percent of its mass-energy budget, Daily Galaxy
WIMP have a very weird behavior, experts suspect. No one was ever able to detect them directly – since dark matter only interacts with baryonic matter through the force of gravity – but theoretical studies suggest that these particles are their own antiparticles.
What this means is that whenever two WIMP meet up, they annihilate each other just as matter and antimatter would. The process releases a rather high amount of energy, primarily as heat and positrons (the positively-charged antimatter equivalents of electrons).
This energy could be converted to heat around exoplanets, say researchers at the US Department of Energy's (DOE) Fermi National Accelerator Laboratory (Fermilab), led by physicist Dan Hooper and astrophysicist Jason Steffen.
Hooper believes that dark-matter-fueled exoplanets are the only hope civilizations such as our own have in surviving over prolonged periods of time. Our Sun, for example, will burn out in about 5 billion years, and then most likely destroy our planet.
If our species is to survive for trillions of years, then these exoplanets may literally act as lifeboats, sailing through empty space. By that time, the Universe would have expanded tremendously, increasing the distance between stars to nearly-unimaginable lengths.