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From PhD stargazer to Nobel Physics laureate

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Swiss astronomer Didier Queloz on Tuesday shared the Nobel Prize in Physics 2019 with compatriot and colleague Michel Mayor and Canadian-American cosmologist James Peebles. AFP

From PhD stargazer to Nobel Physics laureate

As a student astronomer scanning the skies with homemade instruments a quarter of a century ago, Didier Queloz spent months doubting the data that led him to an inescapable conclusion – he’d just discovered the first planet outside Earth’s solar system.

The Swiss scientist had spent much of his PhD research refining techniques to detect so-called exoplanets, which until one fateful night in October 1995 had previously only existed in the realm of science fiction.

Queloz and his colleague Michel Mayor, who on Tuesday were awarded the Nobel Prize for Physics for their pioneering work, had already overcome several obstacles in their galaxy-wide search.

They’d painstakingly constructed their equipment at the Haute-Provence Observatory at the foot of the French Alps, allowing them to detect tiny changes in the frequency of light emitted by stars they suspected were being orbited.

Now they had another problem. The planet they’d discovered, known as 51 Pegasi b, was too big.

“We were as surprised as everybody to find a planet because the planet that we found was bizarre and it’s not at all the way you would have expected a planet to be,” Queloz said on Tuesday.

“I remember many discussions I’d had with Michel and trying to demonstrate that it was not a planet. But in the end, we always circled back and said that that’s the only explanation.”

The exoplanet was roughly the size of Jupiter, yet was more than 20 times closer to its star than Earth is to the Sun.

Such dimensions baffled the team.

Sara Seager, planetary scientist and astrophysicist at MIT, who was a grad student at Harvard when Mayor and Queloz made their discovery, recalled a “huge controversy” at the time.

“No one likes their paradigm to be upset, and we just really wanted to believe everything we were taught in school.

“People were very resistant, and rightly so in science – you can’t see the planet, you don’t have a photo of one, you’re just seeing the star, the effect on the star, so people wanted to put that effect [down] to something else,” she said.

Queloz said the team’s discovery took time to be acknowledged because before the research exoplanets were “stuff for weirdoes” within the astronomy community.

“People were assembling in the corner of a meeting talking but nobody would officially speak about it, it was too bizarre,” he said.

Today, thanks to their pioneering work, there are more than 4,000 known exoplanets and billions of stars thought to be orbited by them.

“We are studying the origins of life and that’s exactly what exoplanets are doing,” Queloz said.

“That’s why the field is growing. Now there must be 1000s of people working on this, which is fantastic.”

And how does it feel to be the newest Nobel Physics Laureate, a quarter of a century after his initial eureka moment? “I can still breathe, which is a good sign,” Queloz said.