As 2015 comes to a close, United Press International made a list of top ten scientific breakthroughs, discoveries, and announcements.

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A new human ancestor: Homo nalendi

In September, scientists announced the discovery of a previously unknown human ancestor, homo nalendi, found in a cave in South Africa. The unearthed fossils represented at least 15 individuals characterized by body mass and stature similar to small-bodied humans.

Free-flowing water on Mars

In September, NASA scientists presented what they said was the strongest evidence yet of the presence of water on Mars: flowing salty streaks of water that vary with the seasons. Scientists were also able to detect the presence of waterlogged molecules, called perchlorates. This discovery makes the presence of living organisms on the planet more likely.