Benvenuti in queste pagine dedicate a scienza ed arte. Amelia Carolina Sparavigna

Friday, April 8, 2011

Planets heated by dark matter

Audacious notion of the week: planets heated by dark matter - March 30, 2011
"It’s dark outside, permanently. The sun twinkles in the distance barely bigger than other stars. But the ground is warm, and oceans are teaming with life. That’s the scenario envisioned by Dan Hooper and Jason Steffen of Fermi National Laboratory in Batavia Illinois, who released a preprint yesterday about the possibility of dark matter heating planets that are otherwise too far from their host stars to be habitable."
More Nature.com

According to Dan Hooper and Jason Steffen, they " have calculated the capture rate of dark matter particles in Earth-like and super-Earth planets, and determined the resulting surface temperature of those planets that would result from dark matter annihilations. While planets in the local region of our galaxy receive only a negligible quantity of energy from dark matter annihilations," the authors" find that planets in dwarf spheroidal galaxies and in the innermost volume of the Milky Way could plausibly accumulate and annihilate enough dark matter to heat their surfaces to temperatures capable of sustaining liquid water, even in the absence of energy from starlight or other standard sources. Although" they "expect ecologically relevant quantities of energy to be released through dark matter annihilations only within the interiors of planets that reside in very special environments (such as near the Galactic Center, or near the center of a dwarf spheroidal galaxy), and only in the case of dark matter models which feature large elastic scattering cross sections with nuclei (near the current upper limits)," the authors "expect that within such models planets will exist which derive enough heat from dark matter to almost indefi nitely sustain surface temperatures suffi cient to yield liquid water. Even in the absence of starlight, such planets could plausibly contain life. And, given their extremely long lifetimes, such planets may prove to be the ultimate bastion of life in our universe."