Spurred on by their success with the Higgs boson, physicists have been studying the small print of the universe and it has given them quite a shock. It turns out that there’s a limited warranty: the cosmos may well vanish from existence at some unspecified point in the future. The only crumb of comfort is that, if it does, there’ll be another one along in a minute.
There is good reason to believe that the universe is a stretched rubber band, ready to ping back at a moment’s notice. More stable universes than ours, more akin to a rubber band sitting peacefully on a table, are possible. And the Higgs boson is at the heart of what turns one into the other.
The Higgs boson arises from a field – the Higgs field – that permeates space and time. You can think of it as elastic that runs through the Lycra of the universe. If it provides too much tension, space and time collapse in on themselves, causing the universe to scrunch up and disappear.
The elastic tension is related to the mass of the Higgs boson: the heavier the boson, the safer we are. However, the boson discovered at the Large Hadron Collider at Cern near Geneva is not quite heavy enough: it’s only 98 per cent of the mass needed to safeguard the universe. That seemingly esoteric discovery made in Switzerland last year has serious historical implications, as it turns out. There may well have been a universe before ours and there’ll probably be one after it.
The standard cosmological story deals with only one universe, in which both time and space began at the Big Bang. Here, our best guess for the origin is that something (its other workings are known to us through quantum theory) created a bubble of energy from nothing. Eventually, this energy blew up to become time, space and matter.
Yet there is another possibility. The instability-inducing Higgs mass is a shot in the arm for a theory that has long been in the shadow of the standard Big Bang model of the universe. Proponents of the “ekpyrotic universe” theory (the word comes from the Greek for “born out of fire”) argue that there has been a succession of bangs and scrunches; the cataclysmic death of every universe brings forth a new one.
It’s not a vague, fanciful notion – it comes from the mathematics of string theory, in which the fundamental constituents of the universe are the result of packets of energy that pulsate in ten-dimensional space (OK, so it’s a bit fanciful). The theory suggests that something like our threedimensional universe can be created when two vast and multidimensional objects collide. The collision simultaneously destroys one universe and creates another.
The ekpyrotic universe model has been around for a while and remains widely unaccepted but there is much to recommend it. To make the standard Big Bang story fit with what we see in the cosmos, we have to introduce a few oddities. One is that the universe is peppered with dark matter, exotic stuff unlike anything else we know. There is also an unexplained source of dark energy: a mysterious force that is causing the expansion of the universe to speed up. Then there’s inflation, a force that made the universe 1060 times bigger in the tiny fraction of a millisecond just after the Big Bang.
However, the ekpyrotic universe doesn’t need a period of inflation and, unlike the standard Big Bang model, it can account for where the dark energy comes from. Now, it has support from the Higgs boson. So, enjoy your 21st-century, ecofriendly, self-recycling universe. Just don’t expect it to last.