Cosmic Dreams

Cosmic Dreams

In India there are many gods, and each god has many manifestations. The Chola bronzes, cast in the 11th century, include several different incarnations of the god Shiva. The most elegant and sublime of these is a representation of the creation of the universe at the beginning of each cosmic cycle, a motif known as the cosmic dance of Shiva. The god, called in this manifestation Nataraja, the Dance King, has four hands. In the upper left hand is a tongue of flame, a reminder that the universe, now newly created, will billions of years from now be utterly destroyed.

These profound and lovely images are a kind of premonition of modern astronomical ideas.

These great ideas are tempered by another, perhaps still greater. It is said that men may not be the dreams of the gods, but rather the gods are de dreams of men. Neither of modern cosmologies may be altogether to our liking.

In one, the universe is created, somehow, ten or twenty billion years ago and expands forever, the galaxies mutually receding until the last one disappears over our cosmic horizon. Then the galactic astronomers are out of business, the stars cool and die, matter itself decays and the universe becomes a thin cold haze of elementary particles.

In the other, the oscillating universe, the Cosmos has no beginning and no end, and we are in the midst of an infinite cycle of cosmic deaths and rebirths with no information trickling through the cusps of the oscillation. Nothing of the galaxies, stars, planets, life forms or civilizations evolved in the previous incarnation of the universe oozes into the cusp, flutters past the Big Bang, to be known in our present universe.

Human beings and our descendants, whoever they might be, can accomplish a great deal in tens of billions of years, before the Cosmos dies. Image: ©  Elena

The fate of the universe in either cosmology may seem a little depressing, but we may take solace in the time scales involved. These events will occupy tens of billions of years, or more.

If the universe truly oscillates, still stranger questions arise. Some scientists think that when expansion is followed by contraction, when the spectra of distant galaxies are all blue-shifted, causality will be inverted and effects will precede causes. First the ripples spread from a point on the water’s surface, then I throw a stone into the pond. First the torch bursts into flame and then I light it. We cannot pretend to understand what such causality inversion means. Will people at such a time be born in the grave and die in the womb? Will time flow backwards? Do these questions have any meaning?

Scientists wonder about what happens in an oscillating universe at the cusps, at the transition from contraction to expansion. Some think that the laws of nature are then randomly reshuffled, that the kind of physics and chemistry that orders the universe represent only one of an infinite range of possible natural laws.