Sunday, November 27, 2011

Could the Higgs boson explain the size of the Universe?

The Universe wouldn’t be the same without the Higgs boson. This legendary particle plays a role in cosmology and reveals the possible existence of another closely related particle.

The race to identify the Higgs boson is on at CERN. This Holy Grail of particle physics would help explain why the majority of elementary particles possess mass. The mysterious particle would also help us understand the evolution of the Universe from the moment of its birth, according to a group of EPFL physicists. If their theory is verified with data from the Planck satellite, it would clear up several questions about the Universe, past and future.

The Universe, which today extends over billions of light-years, was incredibly minuscule at its birth. To simultaneously explain this dichotomy of scale and the fact that matter is seemingly distributed in a homogeneous fashion throughout the Universe, physicists have had to resort to a theoretical trick: they added an inflationary phase to the Big Bang, an initial phenomenal expansion in which the Universe grew by a factor of 10^26 in a very short time. Physicists have a hard time, though, accounting for this rapid growth.

In its first moments, the Universe was unimaginably dense. Under these conditions, why wouldn’t gravity have slowed down its initial expansion? Here’s where the Higgs boson enters the game – it can explain the speed and magnitude of the expansion, says Mikhail Shaposhnikov and his team from EPFL’s Laboratory of Particle Physics and Cosmology. In this infant Universe, the Higgs, in a condensate phase, would have behaved in a very special way – and in so doing changed the laws of physics. The force of gravity would have been reduced. In this way, physicists can explain how the Universe expanded at such an incredible rate.

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