Is there any proof of life on other planets or in other galaxies?
There is currently no proof of life on other planets.
It is very likely that there is life in other solar systems and galaxies. We are finding that most stars have planets, the the odds are high that life has evolved on some of them.
It is believed that life once existed on Mars. The conditions on Jupiter's moon Europa and Saturn's moons Titan and Enceladus are thought to be capable of supporting life.
As yet, we have found no evidence of life outside of the Earth. It is still very early days. Space probes and being sent to Mars to search for signs of life. Space telescopes are actively searching for planets around other stars (exoplanets). As these telescopes get more sensitive we will be able to determine the composition and temperatures of exoplanets and look for the signatures of life.
So, as yet there is no proof of life on other planets, but hopefully soon there will be.