“For the last century the biggest bar fight in science has been between Albert Einstein and himself,” reports the New York Times:
On one side is the Einstein who in 1915 conceived general relativity, which describes gravity as the warping of space-time by matter and energy. That theory predicted that space-time could bend, expand, rip, quiver like a bowl of Jell-O and disappear into those bottomless pits of nothingness known as black holes. On the other side is the Einstein who, starting in 1905, laid the foundation for quantum mechanics, the nonintuitive rules that inject randomness into the world — rules that Einstein never accepted. According to quantum mechanics, a subatomic particle like an electron can be anywhere and everywhere at once, and a cat can be both alive and dead until it is observed. God doesn’t play dice, Einstein often complained.
Gravity rules outer space, shaping galaxies and indeed the whole universe, whereas quantum mechanics rules inner space, the arena of atoms and elementary particles. The two realms long seemed to have nothing to do with each other; this left scientists ill-equipped to understand what happens in an extreme situation like a black hole or the beginning of the universe.
But a blizzard of research in the last decade on the inner lives of black holes has revealed unexpected connections between the two views of the cosmos. The implications are mind-bending, including the possibility that our three-dimensional universe — and we ourselves — may be holograms, like the ghostly anti-counterfeiting images that appear on some credit cards and drivers licenses. In this version of the cosmos, there is no difference between here and there, cause and effect, inside and outside or perhaps even then and now; household cats can be conjured in empty space. We can all be Dr. Strange.
“It may be too strong to say that gravity and quantum mechanics are exactly the same thing,” Leonard Susskind of Stanford University wrote in a paper in 2017. “But those of us who are paying attention may already sense that the two are inseparable, and that neither makes sense without the other.”
That insight, Dr. Susskind and his colleagues hope, could lead to a theory that combines gravity and quantum mechanics — quantum gravity — and perhaps explains how the universe began.
