And if the Universe was only one among many others? The hypothesis is disturbing, it questions our conception of the cosmos, it invites us to rethink space-time.
And if the Universe was only one among many others? The hypothesis is disturbing, it questions our conception of the cosmos, it invites us to rethink space-time. It completes the lesson of humility that astrophysics has been teaching us since the Copernican revolution 500 years ago. No, our Earth is not the center of everything, it is only one of the hundreds of billions of planets in the Milky Way, which is only one galaxy among more than 2,000 billion others in the visible universe. And now our Universe itself could be only a tiny part of the multiverse! Pure science fiction? Not at all: in reality, most current cosmological models predict the existence of a profusion of these famous parallel universes so dear to the big screen …

Read also: Would there be a mirror universe on the other side of the Big Bang?

Starting, even, with the theory that has been the reference for more than a century: Einstein’s General Relativity! This theory of gravitation states that space-time is not fixed: it deforms and bends in the presence of matter or energy.

According to Relativity, space could extend to infinity, or loop back on itself in three dimensions,” describes Benjamin Wandelt, professor of astrophysics and member of the Planck collaboration. Now, if the Universe is infinite, then it is obligatory: there exists somewhere in space-time a planet similar to the Earth populated by our look-alikes, a true parallel world! This is because in infinity, everything that has a non-zero probability of occurring… necessarily occurs, and an infinite number of times: there would therefore be infinite Earths!