Mars may have been habitable much more recently than thought - Harvard Gazette

"The study indicates that Mars' protective magnetic field may have lasted until about 3.9 billion years ago, which is significantly later than previous estimates of 4.1 billion years."

"The research team conducted simulations of the Martian surface that suggest the conditions supporting a life-enabling atmosphere could have persisted for hundreds of millions of years longer than previously thought."

Read at Harvard Gazette