2019 Nobel prize: physics

What was the 2019 Nobel Prize for Physics all about?
15 October 2019

Interview with 

Ben McAllister, UWA


Artist rendering of three exoplanets


Recently, some of the world’s biggest scientific brains have been receiving telephone calls from Stockholm. Those calls are to announce that they’ve won one of science’s highest accolades: A Nobel Prize. So we’ve asked three scientists at the beginnings of their research careers to tell us who’s won what in their respective fields. Up first, to tell us about the Physics Prize, from the University of Western Australia, in Perth, particle physicist Ben McAllister…

Ben - The drive to discover more about the nature of the Universe has long been one of humanity’s most fundamental instincts. So it’s no surprise that this year’s Nobel Prize in Physics has been awarded to three people who have devoted their lives to a deeper understanding of the cosmos.

The prize was split into three parts - one half of it going to James Peebles of Princeton University, and the other half being split between Michael Mayor and Didier Queloz who were both at the University of Geneva at the time of their Nobel work.

Peebles was one of a team involved in the discovery and understanding of the Cosmic Microwave Background - the leftover radiation from the very birth of the universe, which permeates space and is detectable with radio telescopes today.

Comprehending the Cosmic Microwave Background led to a significant leap forward in our understanding of the early universe, specifically a process known as inflation, which occurred shortly after the Big Bang, where the universe expanded extremely rapidly from its original tiny size.

Mayor and Queloz, on the other hand, have been more experimental, and have found some truly incredible things. For hundreds of years, scientists suspected that distant stars could have planets orbiting them. These supposed planets became known as exoplanets. But, until relatively recently, no planets outside our solar system had ever been detected.

Mayor and Queloz exploited that fact that the gravitational pull of an orbiting planet pulls slightly on its parent star, making it “wobble”. This creates tiny - but detectable - shifts in the spectrum of the light that they emit.

By searching for those small shifts, Mayor and Queloz proved the existence of planets orbiting distant stars. Using this and other techniques, astronomers following in their footsteps have since detected thousands more exoplanets.

This was a remarkable discovery, as it suggested the possibility of Earth-like planets orbiting Sun-like stars elsewhere in space, which has massive implications for our understanding of our place in the cosmos…


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