Time Without End
BY ADRIAN BERRY
Posted: April 16, 2008
DO diamonds really last for ever, as the title of the James Bond story suggests? Until very recently the surprising answer was “no”; nothing was going to last for ever. No object, be it planet, star, galaxy or diamond necklace would survive when the atoms that comprised them disintegrated.
This theory of “proton decay” posed no immediate threat. No disintegration of matter will be complete in less than 1030 years, a 1 followed by 30 noughts or a million trillion trillion. But the theory was none the less depressing.
Huge though this number is, it is the merest snap of the fingers compared with eternity, the timespan promised by the continued existence of time and space in the open universe.
The theory therefore suggested that for all of eternity (after the trifling future period of 1030 years), the universe would be absolutely empty. There would be no possibility of life, matter–or even light. It would be a cosmos of nothingness. There seemed to be no chance that a divine being might exist, for what deity would wish to rule over a dead universe? I became an atheist at once on hearing of it.
But happily for those of religious–or at least agnostic– inclination, the theory of proton decay seems to be wrong. All the experiments designed to test it have so far found nothing.
The biggest of these is an artificial lake containing 50,000 tons of pure water at Kamiokande, Japan, 3,000 feet underground to avoid contamination by cosmic rays. The lake, like several other underground bodies of water, has been constantly monitored for flashes of so-called Cerenkov radiation that occur when a molecule of water disintegrates, but without success.
The idea behind these experiments is that proton decay is a random process. Testing for it is like throwing dice. There's more chance of throwing a six if many dice are thrown rather than just one. So there's a greater chance of seeing proton decay if huge numbers of protons are observed, since a few protons would be decaying all the time. Hence these underground lakes.
But nothing has been found. In the words of Peter Woit, of Columbia University, New York: “It is becoming increasingly unlikely that proton decay occurs at an experimentally observable rate.” Or, as some might say, it is becoming increasingly unlikely that it occurs at all.
So for how long will the universe remain habitable? For how many years could a deity be expected to rule over it, if a deity existed? If protons do not decay, we can contemplate a far more optimistic vision of the extreme long-term future. Back in 1979, the great physicist Freeman Dyson did an astonishing calculation of the amount of time in which life could continue. See his paper “Time Without End: Physics and Biology in an Open Universe”, (www.aleph.se/Trans/Global/Omega/dyson.txt).
Dyson believes that the acceleration of the expansion of the universe may be a temporary phenomenon. If it is, then intelligent life will be possible in the cosmos for:
10 to the power of (1076) years
Note the brackets surrounding the upper two numbers. This is an inconceivably gigantic number. No imaginable computer could handle it. To write it down in the ordinary way, using digits like 123456.... etc, even if one could write down a trillion digits every second, would take no less than 1084 years!
We are looking forward to a time long after all the stars have ceased to shine, even those that have not yet been born, when there is no longer any hydrogen to make them shine.
But there is no reason why advanced beings should not continue to exist, in sunless temperatures only a few tens of degrees above absolute zero.
They might take the form of intelligent clouds of gas, as in Fred Hoyle's 1957 novel The Black Cloud. Perhaps, to quote Dyson, they could dwell in a “universe growing without limit in richness and complexity, a universe of life surviving forever and making itself known to its neighbours across unimaginable gulfs of space and time.” What gods will these beings worship?
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Visit Adrian Berry's website at www.adrianberry.net He is Consulting Editor (Science) of the Daily Telegraph.