Oxygen is a signal of life on our own planet, but that's not necessarily the case elsewhere. Particularly when it comes to young planets, signs of oxygen do not necessarily indicate the presence of biological processes, new research argues.
Water vapor in the upper atmosphere of a young planet could break into hydrogen and oxygen by incoming ultraviolet and extreme ultraviolet rays from the parent star.
"Atomic hydrogen is so light that it can escape to space and lead to the oxidization of the planet," said Robin Wordsworth, a geophysicist at the University of Chicago. "It will just keep continuing and oxidizing the atmosphere. That’s what we try and investigate in the paper.”