Extraterrestrial life has never been discovered, but that doesn’t mean it doesn’t exist.

We stand at a crossroads in the search for life. We’ve found thousands of planets in our Milky Way galaxy, a large fraction of them in Earth’s size range and orbiting in their stars’ “habitable zones” – the distance from the star at which liquid water could exist on the surface. We know the galaxy likely holds trillions of planets. Our telescopes in space and on the ground, and our remote-sensing technology, grow ever more powerful. Yet so far, the only life we know of is right here at home. For the moment, we’re staring into the void, hoping someone is staring back.

Observations from the ground and from space have confirmed thousands of planets beyond our solar system. Our galaxy likely holds trillions. But so far, we have no evidence of life beyond Earth. Is life in the cosmos easily begun, and commonplace? Or is it incredibly rare?

https://science.nasa.gov/exoplanets/search-for-life/