NASA holds a news conference to discuss the close encounter of Comet Siding Spring with Mars. On October 19, 2014, the comet will pass 139,500 kilometers (88,000 miles) from the red planet.
Where did the two natural satellites of Mars, Phobos and Deimos, come from? For a long time, their shape suggested that they were captured asteroids. However, the shape and course of their orbits contradict this hypothesis. Two independent and complementary studies now provide an answer: these satellites formed from the debris of a gigantic collision between Mars and a protoplanet one-third its size.
While Mars doesn’t have much in the way of Earth-like weather, it does evidently share one kind of weird meteorology: acid fog. Planetary scientist Shoshanna Cole has pieced together a compelling story about how acidic vapours may have eaten at the rocks in Gusev Crater on Mars using a variety of data gathered by instruments on the 2003 Mars Exploration Rover Spirit.
NASA’s new planet-hunting TESS observatory completed its first post-launch thruster firing Saturday, setting up for a big boost Wednesday that will send the spacecraft toward the moon for a flyby next month, the next maneuvers in a two-month process to reach the mission’s final science orbit in mid-June.