A team of the US space scientists believes that if they can spot oxygen on other planets it'll lead them to extraterrestrial life.
They say they have come up with a technique to do this using a very special super-strength telescope.
But what does it all really mean and how will it be done?
Okay, so this could be a little bit of a let down - extraterrestrial life simply means life outside of Earth.
So, this could be anything from space plants or tiny organisms to the little green guys we all wonder about.
Nasa has developed a technique to help them spot oxygen gas on planets other than Earth.
If there is oxygen on a planet then the likelihood is that there is some form of life there too!