The deeper we look into space, the more places we come across that seem like maybe, just maybe, they could host life. From our neighboring planets to distant galaxies sending out weird signals, the list of spots in space worth checking out just continues to grow.
The closest world we should check for signs of life is one we’ve already been to, or at least our robots have. There’s increasing evidence that Mars was once a lot more like Earth, with oceans on its surface. Today it’s more harsh, but it’s not out of the question that we could find some sort of microbes in Martian soil.