One world is not enough

On inaccessible universes and infinite planets.

Don’t worry, there are other worlds. There have to be. If there aren’t, then we haven’t yet made sense of this one. On 19 June, the celebrated science-fiction writers Terry Pratchett and Stephen Baxter will publish a new book, The Long Earth. It is based on an outlandish premise: that an infinite number of variations on our planet are hidden in inaccessible universes. If it were just science fiction, we could either welcome or dismiss it, according to our taste, as yet another example of the limitless human imagination. The trouble is, the whole thing is based in evidence. Worse, this evidence is now the bedrock of modern science.

First of all, let’s go to the roots of our physical reality. If you fire an atom at a screen containing two openings, the atom will go through both. It’s not just atoms; a molecule composed of 60 or so atoms does the same thing. Anything that follows the laws of quantum theory will do it. The only time this doesn’t happen is when someone is watching.

That we don’t get into a car using all four doors at once tells us that the weirdness disappears once you have a lot more than a few dozen atoms clumped together. No one knows why, and it doesn’t change the fact that the strange behaviour of the building blocks of matter is capable of breaking your mind.

No one knew this better than Hugh Everett, who started his career trying to solve this puzzle and ended up a chain-smoking alcoholic. Everett’s idea is now known as the “many worlds” interpretation of quantum mechanics. According to this, a new universe is created every time a subatomic particle is faced with a choice of things to be or do. The ultimate logical consequence is that the universe is composed of myriad sub-universes, each subtly different from the one that spawned it. In this cornucopia of worlds, many will be utterly different from ours. There is, according to the theory, a world where Elvis Presley is the king, not of rock’n’roll, but of Great Britain and Northern Ireland.

No one accepted the idea, and Everett responded to the pain of rejection by slowly self-destructing. Today, however, physicists take these quantum worlds seriously. And they are not the only strange fruit of modern physics.

Our best theory of how the universe began requires that it went through a ridiculous period of super-fast expansion, increasing in size by a factor of 1,000 billion billion billion in a fraction of a millisecond. If that is the case, the same “inflation” mechanism will cause other universes to blow up from tiny instabilities in the fabric of our universe. They pinch off and float away beyond our reach. And if you believe Everett’s theory, the activity of quantum particles in each of those worlds will spawn ever more worlds nested within them.

Forget reality

It might seem as if the existence of these universes would be unverifiable, but that is a supposition which ignores the ingenuity of scientists. Some have already worked out what imprint a collision with one of the inflated universes would make on the microwave background radiation that fills our universe. Having figured that out, they are now combing the universe for signs that we have touched another world.

It will be harder to verify the existence of the many quantum worlds. Some believe a better explanation for quantum phenomena is that there is no objective reality at all; nothing exists until an experimental observation brings it into being. But clearly, whatever Pratchett and Baxter have come up with, it won’t be as strange or unbelievable as the truth. 

Michael Brooks’s “The Secret Anarchy of Science” is out now in paperback (Profile Books, £8.99)

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is At the Edge of Uncertainty: 11 Discoveries Taking Science by Surprise.

This article first appeared in the 18 June 2012 issue of the New Statesman, Drones: video game warfare

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How the Night Tube could give London’s mice that Friday feeling

London Underground’s smaller inhabitants might be affected by the off-squeak service – and learn when the weekend’s coming up.

What will the mice who live in the Tube network make of the new all-night service? Half a million of them are thought to have made the London Underground their home – and will be in for a surprise when the Victoria and Central lines keep running this weekend.

The Londonist is concerned the mice “are unlikely to get any sleep” with the new Night Tube, and may move to the District line instead. Yet a number of scientists point out to the New Statesman that mice are nocturnal creatures, most likely to sleep while the lights are on and the trains are running.

So will they get on board with the change – or make a run for different platforms on other lines?

The bad news:

“When the Tube’s away, the mice will play,” is how the rhyme (almost) goes. 

Many have come to know  and even love  the mischiefs of the mice who stream off the tracks and out of the tunnels as the stations close at night, in search of discarded morsels of Maccy D. And until now, they’ve had a good few hours to conduct such galavanting in peace. But the new system means they will have to re-structure their sleep and foraging cycles, or “circadian rhythms”. 

“The presence of night trains should upset several of these entrainment factors (or zeitgebers = time givers) leading to disturbances in their behaviours,” explains Professor Patrick Nolan, from MRC Harwell, an international centre for mouse genetics. 

“When you fly across the Atlantic, for example, it takes a few days to adapt, you feel a bit groggy, don't perform as well as you usually do, don't eat well, etc. You soon adapt to the change. But if there are constant disruptions like this, the effect may be more severe and long-lasting. And this is how the schedule changes in the Underground might affect the resident mice.” 

So it's the constant switching between the week and weekend schedules that could leave the mice  and Tube drivers  most cheesed off. Agoraphobia (fear of open spaces) and photophobia (sensitivity to light) are two possible effects of the resulting anxiety, and their mating patterns and liver functions are also likely to be disturbed.

The good news:

Yet it is unlikely mice will be leaving the Night Tubes for good. 

The more time we humans have to drop our dinners, the larger the menu becomes for the mice (researchers tell me that strawberry milk and Wheetos are particularly favoured fare).

“Mice are active most of the time – so more trains at night hours will not make such a difference to them,” say the RSPCA’s wildlife officers. “In fact, it may help as it may provide more foraging opportunities.”

They’ve also faced worse before. The London Transport Museum reminds us that, during the Second World War, cats were employed to counter vermin on the network (spot the cat in the 1940s TfL workers' canteen below).


Credit: London Transport Museum

For Dr Samuel Solomon at UCL, there is plenty to suggest the mice will successfully adapt. His study of mouse reflexes shows how they respond to various visual stimuli – and can start running within one-tenth of a second. “There might be cues they pick up – if people clean the station differently on Fridays, for instance.”

The tracks’ electric current may no longer be entirely switched off (if it ever was), but their whiskers’ sensitivity to vibrations could help them juggle their escapades to fit around the Night Tube’s less frequent service.

What Dr Soloman can’t yet predict is whether the mice will start to anticipate that Friday feeling: “It will be interesting to see whether they can learn that Friday is Friday”.

All in all, the Tube mice seem well set for the Night Tube’s new challenge. Who knows, they may soon gain the confidence of their 24/7 brothers in New York – and start ordering take-out...

India Bourke is the New Statesman's editorial assistant.