Light-colored mounds of a mineral deposited on a volcanic cone more than three billion years ago may preserve evidence of one of the most recent habitable microenvironments on Mars.

While most planetary scientists believe water on Mars is the best clue to finding interesting rock samples, there are big questions that remain about where exactly that water may be found. New results give a short-list for some who track the water history on the red planet.

If you have a telescope and don't want to miss out on an astronomical event that will next occur in 2287, wrap up warmly and head outside. Earth and Mars are currently hurtling towards a rare rendezvous on August 27, when they will pass as close as possible.