How the presence of oxygen and other disequilibrium gases could signpost life.
New research has revealed that a giant impact on Mars more than four billion years ago would explain the unusual amount of "iron loving" elements in the Red Planet.
Mars' Gale Crater, once home to a flowing river and a lake, had the right conditions for life in ancient times, according to a new study looking at three years of data from NASA's Curiosity rover.
It is thought that animal life first arose during the Ediacaran Period, between 635 and 541 million years ago, but these organisms bore little resemblance to the animals we know today.
In an unlikely scenario, the impacts that created the craters that became Canada's two Clearwater Lakes apparently occurred almost 200 million years apart.
Life on other planets could draw from thousands of amino acids to build proteins, not just the limited ones used on Earth.
The colors of planets beyond the solar system could indicate whether or not they're friendly to life.