Ancient Mars bombardment likely enhanced life-supporting habitat

The bombardment of Mars some 4 billion years ago by comets and asteroids as large as West Virginia likely enhanced climate conditions enough to make the planet more conducive to life, at least for a time, says a new study.
Researchers from University of Colorado Boulder said if early Mars was as barren and cold as it is today, massive asteroid and comet impacts would have produced enough heat to melt subsurface ice. The impacts would have produced regional hydrothermal systems on Mars similar to those in Yellowstone National Park, which today harbor chemically powered microbes, some of which can survive boiling in hot springs or inhabiting water acidic enough to dissolve nails.

https://www.sciencedaily.com/releases/2016/04/160405105606.htm

Paper: http://www.sciencedirect.com/science/article/pii/S0012821X16300528