Mars is a large enough planet that astrobiologists looking for life need to narrow the parameters of the search to those environments most conducive to habitability.
NASA's Mars Curiosity mission is exploring such a spot right now at its landing site around Gale Crater, where the rover has found extensive evidence of past water and is gathering information on methane in the atmosphere, a possible signature of microbial activity.
But where would life most likely gain energy from its surroundings? One possibility is in an environment that includes “green rust,” a partially oxidized iron mineral. A fully oxidized iron “rust” — one exposed to oxidation for long enough — turns orangey-red, similar to the color of Mars' regolith. When oxidization is incomplete, however, the iron rust is greenish.
The supermassive black hole is 40 million times as massive as the sun and powers a quasar that existed 700 million years after the Big Bang.
The asteroid zoomed by Earth at a perfectly safe distance of around 1.8 million miles (2.9 kilometers).
Images show surprise changes to the spacecraft as it interacted with the atmosphere.
