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Why Didn’t the Universe Immediately Crunch Into Nothing? Gravity, Say Physicists

The Higgs boson and cosmic inflation can coexist after all.
​Image: geralt/Pixabay 

​One of the disquieting implications of the Higgs boson is that the universe should not exist.

While cosmic inflation coupled with a newly formed Higgs field would seem to demand an immediate post-Big Bang collapse to everything, well before mass could even be created, we're clearly here and, thus, something in our theories and observations is broken.

According to a paper published in this week's Physical Review Letters, that may be our view of gravity.

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Last summer, a particular science-bite became white hot, particularly among creationists and other shady science-skeptical sorts: The mere existence of the Higgs boson, the god particle, implies that the universe should not exist. In order for both the highly popular theory of cosmic inflation and the observed Higgs boson to coexist, the universe should have vanished in a "Big Crunch."

The idea is that after the Big Bang, the newborn universe was just a manic wad of energy. Mass didn't exist yet, nor did organization, and everything was free to zip around at the speed of light.

As things cooled, features emerged, like condensation on the side of a cold glass. The fundamental forces crystallized—electromagnetism, the weak and strong forces, gravity—and with them, mass. Mass was the result of the newly condensed/emerged Higgs field, a feature that came into being as the universe settled into its current energy resting state.

What should have happened, at least in the absence of some other force or influence, is an interaction between the newborn Higgs field and the quantum fluctuations behind ​zero-point energy—the energy allowed/demanded by what would otherwise be perfect emptiness. This interaction would have supplied enough juice to the Higgs field such that the laws that had condensed out of the early featureless universe would again vaporize, at least partway.

But the universe would continue cooling and a Higgs field would again condense, only this time it might be at a much lower energy resting state, maybe the lowest. Cosmic collapse would then be inevitable and existence itself would disappear in a dimensionless ball of eternity.

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As you may have noticed, this didn't happen.

It could be that everyone is wrong about inflation, or there may be an explanation that's as yet undiscovered. ​New Physics is one possibility, some force that doesn't appear in the current Standard Model. That's reasonable: The model has holes and it's less a question of New Physics existing than it is of New Physics being found. Take the Higgs boson itself: Physicists knew it had to exist ​some 50 years before actually detecting it.

Image: Yinweichen/Wiki

This week's study suggests that gravity itself would have been enough to correct the situation. The early universe, even before mass, would have experienced gravity. So, it would have existed within a ​curved spacetime; gravity warps space, pulling and stretching it as if space itself was the unseen surface of a trampoline.

The problem with gravity is that physicists haven't really figured out how or in what form it exists at the scale of particles, or within the quantum universe of the very, very small. It's possible that gravity's influence on the Higgs field would be enough to correct its inflationary instability.

"Our research investigates the last unknown parameter in the Standard Model, the interaction between the Higgs particle and gravity," explained Arttu Rajantie, the study's lead author and a physicist at Imperial College, in a statement.

"This parameter cannot be measured in particle accelerator experiments," he said, "but it has a big effect on the Higgs instability during inflation. Even a relatively small value is enough to explain the survival of the universe without any new physics!"

Rajantie and his team hope that future observations of gravitational waves in the ​Cosmic Microwave Background might reveal more about what this space-time curvature might have looked like in the primordial cosmos. But don't worry: With dark matter and antimatter and supersymmetry all still looming, New Physics isn't about to disappear anytime soon.