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Be warned, this could be the matrix
The Sydney Morning Herald
The multiverse theory has spawned another - that our universe is a simulation, writes Paul Davies.
If you've ever thought life was actually a dream, take comfort. Some pretty distinguished scientists may agree with you. Philosophers have long questioned whether there is in fact a real world out there, or whether "reality" is just a figment of our imagination.
Then along came the quantum physicists, who unveiled an Alice-in-Wonderland realm of atomic uncertainty, where particles can be waves and solid objects dissolve away into ghostly patterns of quantum energy.
Now cosmologists have got in on the act, suggesting that what we perceive as the universe might in fact be nothing more than a gigantic simulation.
The story behind this bizarre suggestion began with a vexatious question: why is the universe so bio-friendly? Cosmologists have long been perplexed by the fact that the laws of nature seem to be cunningly concocted to enable life to emerge.
Take the element carbon, the vital stuff that is the basis of all life. It wasn't made in the big bang that gave birth to the universe. Instead, carbon has been cooked in the innards of giant stars, which then exploded and spewed soot around the universe.
The process that generates carbon is a delicate nuclear reaction. It turns out that the whole chain of events is a damned close run thing, to paraphrase Lord Wellington. If the force that holds atomic nuclei together were just a tiny bit stronger or a tiny bit weaker, the reaction wouldn't work properly and life may never have happened.
The late British astronomer Fred Hoyle was so struck by the coincidence that the nuclear force possessed just the right strength to make beings like Fred Hoyle, he proclaimed the universe to be "a put-up job". Since this sounds a bit too much like divine providence, cosmologists have been scrambling to find a scientific answer to the conundrum of cosmic bio-friendliness.
The one they have come up with is multiple universes, or "the multiverse". This theory says that what we have been calling "the universe" is nothing of the sort. Rather, it is an infinitesimal fragment of a much grander and more elaborate system in which our cosmic region, vast though it is, represents but a single bubble of space amid a countless number of other bubbles, or pocket universes.
Things get interesting when the multiverse theory is combined with ideas from sub-atomic particle physics. Evidence is mounting that what physicists took to be God-given unshakeable laws may be more like local by-laws, valid in our particular cosmic patch, but different in other pocket universes. Travel a trillion light years beyond the Andromeda galaxy, and you might find yourself in a universe where gravity is a bit stronger or electrons a bit heavier.
The vast majority of these other universes will not have the necessary fine-tuned coincidences needed for life to emerge; they are sterile and so go unseen. Only in Goldilocks universes like ours where things have fallen out just right, purely by accident, will sentient beings arise to be amazed at how ingeniously bio-friendly their universe is.
It's a pretty neat idea, and very popular with scientists. But it carries a bizarre implication. Because the total number of pocket universes is unlimited, there are bound to be at least some that are not only inhabited, but populated by advanced civilisations - technological communities with enough computer power to create artificial consciousness. Indeed, some computer scientists think our technology may be on the verge of achieving thinking machines.
The Sydney Morning Herald
The multiverse theory has spawned another - that our universe is a simulation, writes Paul Davies.
If you've ever thought life was actually a dream, take comfort. Some pretty distinguished scientists may agree with you. Philosophers have long questioned whether there is in fact a real world out there, or whether "reality" is just a figment of our imagination.
Then along came the quantum physicists, who unveiled an Alice-in-Wonderland realm of atomic uncertainty, where particles can be waves and solid objects dissolve away into ghostly patterns of quantum energy.
Now cosmologists have got in on the act, suggesting that what we perceive as the universe might in fact be nothing more than a gigantic simulation.
The story behind this bizarre suggestion began with a vexatious question: why is the universe so bio-friendly? Cosmologists have long been perplexed by the fact that the laws of nature seem to be cunningly concocted to enable life to emerge.
Take the element carbon, the vital stuff that is the basis of all life. It wasn't made in the big bang that gave birth to the universe. Instead, carbon has been cooked in the innards of giant stars, which then exploded and spewed soot around the universe.
The process that generates carbon is a delicate nuclear reaction. It turns out that the whole chain of events is a damned close run thing, to paraphrase Lord Wellington. If the force that holds atomic nuclei together were just a tiny bit stronger or a tiny bit weaker, the reaction wouldn't work properly and life may never have happened.
The late British astronomer Fred Hoyle was so struck by the coincidence that the nuclear force possessed just the right strength to make beings like Fred Hoyle, he proclaimed the universe to be "a put-up job". Since this sounds a bit too much like divine providence, cosmologists have been scrambling to find a scientific answer to the conundrum of cosmic bio-friendliness.
The one they have come up with is multiple universes, or "the multiverse". This theory says that what we have been calling "the universe" is nothing of the sort. Rather, it is an infinitesimal fragment of a much grander and more elaborate system in which our cosmic region, vast though it is, represents but a single bubble of space amid a countless number of other bubbles, or pocket universes.
Things get interesting when the multiverse theory is combined with ideas from sub-atomic particle physics. Evidence is mounting that what physicists took to be God-given unshakeable laws may be more like local by-laws, valid in our particular cosmic patch, but different in other pocket universes. Travel a trillion light years beyond the Andromeda galaxy, and you might find yourself in a universe where gravity is a bit stronger or electrons a bit heavier.
The vast majority of these other universes will not have the necessary fine-tuned coincidences needed for life to emerge; they are sterile and so go unseen. Only in Goldilocks universes like ours where things have fallen out just right, purely by accident, will sentient beings arise to be amazed at how ingeniously bio-friendly their universe is.
It's a pretty neat idea, and very popular with scientists. But it carries a bizarre implication. Because the total number of pocket universes is unlimited, there are bound to be at least some that are not only inhabited, but populated by advanced civilisations - technological communities with enough computer power to create artificial consciousness. Indeed, some computer scientists think our technology may be on the verge of achieving thinking machines.
