For more than a century, the idea that life might have arrived on our planet from elsewhere in the cosmos sat at the fringes ...

Evidence is mounting that the same basic chemistry that made Earth habitable is unfolding, or once unfolded, on Mars. From ...

During Earth's ancient Snowball periods, when the entire planet was wrapped in ice, life may have endured in tiny meltwater ponds on the surface of equatorial glaciers. MIT researchers discovered that ...