As I said before, there is a chance that extraterrestrial life exist, but if they would exist in the Milky Way alone, we would know that by know. There is a shitload of many complex and huge solar systems across the galaxy, but in order for lifeforms to live, there have to be water. Although there is water, life requires a whole bunch chemical materials. Scientists have even found water in the freezing atmosphere of Jupiter, Neptune etc. However, that water is waaaay to frozen to actually create life. It either has to be liquid, or just plain gas (steam). But yeah, scientists have found water in clouds less than a light year away, in the constellation Orion.