When Jane Austen wrote, in the opening words of Pride and Prejudice about universal truth (“It is a truth universally acknowledged, that a single man in possession of a good fortune must be in want of a wife”) she almost certainly assumed that there was only one universe. As did I, as a schoolboy, when I wrote my address as
34 Beaufort Road
The Solar System
I might of course have identified our galaxy after the solar system bit if I had known that there are in fact a couple of hundred billion other galaxies. And that our galaxy, saddled with the somewhat pedestrian name of The Milky Way which makes is sound like a boring cul-de-sac in a universal council estate just up the road from Mandela Drive or Livingstone Crescent, is nothing very special.
Good old Jane, and all the other schoolteachers of small boys might have said, “Uni. From the Latin, meaning one. By definition, the universe is the thing that there is only one of”. But it is not that simple, as Lewis Carroll observed in Through the Looking-Glass:
“When I use a word,” Humpty Dumpty said, in rather a scornful tone, “it means just what I choose it to mean—neither more nor less.”
Words are cheap, of course, but as the passage goes on:
“When I make a word do a lot of work like that,’ said Humpty Dumpty, ‘I always pay it extra.”
In this case the “extra” comes in the form of the very expensive Planck telescope, which was launched into orbit by the European Space Agency in 2009, and which now makes maps of the cosmic microwave background left by big bang. We all know these days that big bang was the big deal 13.8 billion years ago, and that the universe is what resulted from big bang.
Now, here comes the interesting bit, courtesy of Laura Mersini-Houghton, an Albanian cosmologist and theoretical physicist, now a professor at the University of North Carolina at Chapel Hill. She has been saying for ages that we should not take it for granted that there was only one big bang, and has been predicting that a careful look at the CMB data from Planck might well provide evidence of other universes. And now we have a hunk CMB data, hey presto, she and others are saying, yes, there are other universes, created by other big bangs. Other say, no, no no, not at all, the anomalies in the data are just noise. The jury, as they say, is still out on this one. But it seems that Laura might be onto something, not least because it seems that she accurately predicted the results from Planck before they came in, which is always a sign that a theoretic physicist might well be onto something.
Personally, not having a Planck telescope of my own, I have always assumed multiple big bangs, but separated in time rather than in space. In other words, I have assumed that the universe oscillates in time. Big bang, everything scatters, including black holes, which eventually get bigger and bigger and join up until the whole universe is sucked back into a single universal black hole, when a few billions years after the last one: “BANG” and off we go again.
Anyway, there might be more than one such system. And we had better get used to the idea that the word “universe” does not mean everything, but that which results from a big bang. And the prospect that the cosmologists may well be arguing for a while yet about how many big bangs feature in our space-time continuum.
Meanwhile, schoolboys might well add “Multiverse” to the end of their address.