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Strong geological evidence that Mars once had liquid water on its surface has been revealed this week. Scientists analysing data sent back from NASA and ESA Mars orbiters say that the McLoughlin Crater, caused by a meteor impact millions of years ago, was probably once filled with water. It is likely that the water originated deep under the surface of the Red planet, where microbial life could have lurked.

Domestication of dogs
New genetic analysis of dogs and their pack-hunting ancestors shed light on how dogs descended from wolves, from behavioural changes to dietary adaptation.

Cataloguing life on Earth
How many of Earth's plants and animals still need to be discovered and classified? Not as many as some people think. A review in the journal Science this week, states that there are enough professional taxonomists and amateurs looking for, and classifying new species around the world to be able to complete the job by the end of this century. It'll take some funding, but if we know what we have to lose, we might take better care of it.

(Photo credit: NASA/Getty Images)