What does it mean to be “alive”? Astrobiologists such as Nathalie Cabrol must contend with the lack of a concrete answer as they explore the universe looking for something out there that can properly ...

It began the way many discoveries do — a tickling of curiosity in the back of someone’s mind. That someone was astronomer and communicator Carl Sagan. The thing doing the tickling was the trajectory ...

According to a new study, living cells outnumber stars in the universe, highlighting the deep, underrated link between geophysics and biology. By Dennis Overbye What’s in a number? According to a ...