Do aliens exist?

Well I am a sceptic, but not close minded. It is probable that life exist elsewhere in the universe. However what is the likelihood that aliens are capable of visiting us? I'm not saying that there can't be intelligent life or even superior beings out there. Man has been to the moon and sent satellites out to explore our solar system and beyond. Where can we make it in another thousand years? What if intelligent beings had a headstart on us; they may be capable of long distance space exploration.