Why didn't the universe collapse after the Big Bang? It's a question of gravity

Not only does gravity keep us safely on the ground and hold the planets in alignment, but now it may soon get the credit for saving the whole universe. Physicists at the Imperial College London and the Universities of Copenhagen and Helsinki believe that the interaction between Higgs boson particles and gravity had a stabilizing effect on the very early universe, thereby preventing the Big Crunch – a catastrophic collapse into nothing – from occurring shortly after the Big Bang.

Without this interaction, the Higgs field – which is uniform throughout the universe and is responsible for giving matter mass – would have gained too much energy and kicked the universe over a very high energy hill and then down into a deep valley of energy space. In a matter of microseconds, the universe would then have became too unstable to continue inflating and collapsed in on itself.

But the researchers suggest that the curving of space-time – gravity – held everything together, preventing decay. "[The interaction between the Higgs particle and gravity] cannot be measured in particle accelerator experiments, but it has a big effect on the Higgs instability during inflation," explains Imperial College London professor Arttu Rajantie. "Even a relatively small value is enough to explain the survival of the universe without any new physics."

The team hopes to measure this interaction using cosmological data from current and future European Space Agency missions. "If we are able to do that," says Rajantie, "we will have supplied the last unknown number in the Standard Model of particle physics and be closer to answering fundamental questions about how we are all here."

A paper describing the research was published in the journal Physical Review Letters.

Source: Imperial College London