“In the end, the most improbable and hence the most puzzling aspect of space is its very existence. The simple fact that we live in an apparently smooth and regular three dimensional world represents one of the greatest challenges to the developing quantum theory of gravity,” wrote physicist Lee Smolin in Three Roads To Quantum Gravity. “If you look around at the world seeking mystery, you may reflect that one of the biggest mysteries is that we live in a world in which it is possible to look around, and see as far as we like. The great triumph of the quantum theory of gravity may be that it will explain to us why this is so.”
Perhaps in 10,000 years, or perhaps tomorrow, the inhabitants of Earth will wake up and find an alien spaceship the size of the Moon parked in orbit, writes China’s preeminent ‘hard’ science-fiction author and philosopher of alien contact, Liu Cixin, described as China’s Arthur. C. Clarke. Liu warns that the universe is a “dark forest” and a possible and terrifying reason behind the Fermi Paradox.
“Through how many dimensions and how many media will life have to pass? Down how many roads among the stars must man propel himself in search of the final secret?” asked scientist and philosopher Loren Eiseley with almost poetic, lyrical insight in The Immense Journey.
“Behind every man now alive stand thirty ghosts, for that is the ratio by which the dead outnumber the living. Since the dawn of time, roughly a hundred billion human beings have walked the planet Earth, which is an interesting number, for by a curious coincidence there are approximately a hundred billion stars in our local universe, the Milky Way. So for every man who has ever lived, in this universe there shines a star.
“Today I think we are beginning to suspect that man is not a tiny cog that doesn’t really make much difference to the running of the huge machine, but rather that there is a much more intimate tie between man and the universe than we heretofore suspected. The physical world is in some deep sense tied to the human being. Being homo sapiens, we live on an island –the universe–surrounded by a sea of ignorance. As our island of knowledge grows, so does the shore of our ignorance. But, of all obstacles to a thoroughly penetrating account of existence, none looms up more dismayingly than ‘time.’
The universe we see –stars, moons, planets, galaxies– is but a small, accidental tip of an infinite cosmic iceberg. During the epoch of inflation, thought to have been triggered by the phase transition that marked the end of the grand unification at approximately 10−36 seconds after the Big Bang, the accelerating expansion of space was far more dramatic than in today’s universe, expanding at an absolutely staggering rate, tearing space asunder. During this period no objects—even two elementary particles—remained close enough to one another for long enough to interact.
