The aliens can't exist because it's too outlandish they haven't found us yet. They already destroyed themselves through something like climate change. (Alternatively, they are running the simulation, I suppose). They don't exist: we are living in a computer simulation. They’ll have to set up camp where it’s super cool.' 'Machine-based civilizations, with their massive supercomputers, will have huge problems managing their heat waste. They are too far away because they live at the extreme edge of the universe. We're too remote to notice we live in an otherwise colonised galaxy, like Inuits who didn't know America had been colonised. We are too far away from anyone else to be found because we are in a supervoid. All life, including us, is distributed through the Universe by space dust. is not here” because nobody knows that travel between the stars is possible in the first place.' might exist elsewhere” and the statement “E.T. 'There is no logical contradiction between the statement “E.T. 'Fermi was questioning the feasibility of interstellar travel-nobody thought he was questioning the possible existence of extraterrestrial civilizations.' 'Natural variability will mean that sometimes galaxies will be settled, but often not.' 'Based upon the current state of astrobiological knowledge, there’s a 53 to 99.6 percent chance we are the only civilization in this galaxy and a 39 to 85 percent chance we are the only one in the observable universe.' This contradiction between expectation and observation often goes by the name of the Fermi paradox, and in this talk I discuss a few of the many resolutions that have been proposed.There is no paradox. And yet the universe appears silent and empty. They should have left evidence of their existence - messages artefacts signatures of their technology.

But if we also grant that there is nothing special about humanity's arc of technological progress then it is hard not to conclude that, at some stage in the 13.8-billion-year history of the cosmos, an extraterrestrial civilisation should have disturbed the universe in a way that we could now detect. So if we grant that there is nothing special about our home planet then it is hard not to conclude that life - and presumably intelligent life - exists elsewhere. Our Galaxy contains hundreds of billions of stars and the Universe contains hundreds of billions of galaxies.

Stephen webb fermi paradox