I personally think that there IS possibility of other life in our solar system, either current or in previous millennia, even if this consists of microbial life, I consider it life.
The environmental survivability that we know of just here on earth has shown than life can exist in the harshest of places, and some of the fundamental building blocks for life as we know it have been witnessed from previous scientific missions to Mars.
However what about life as we don’t know it?
Must all life be a carbon based life form?
Is there an alternative to water in which life can prosper?
I can’t say no.
I am a firm believer of evolution and adaptability and in the words of the great Dr. Ian Malcolm in Jurassic Park, “Life, uh, finds a way”.
In fact we know that things like asteroids have hit the Earth and knocked chunks of rock into space, and have hit other planets like Mars and blown chunks of rock into space from them too, and then those chunks of rock have eventually landed on other planets. We’ve actually found lots of Mars rock here on Earth. So it is possible that even if life only started on one planet in our solar system, it would have been spread around to other planets in that way. Actually, we could all be evolved from life that started on Mars in the first place – we could all be Martians!