8 October, 2019
En 2012, el Premio Fronteras Ciencias Básicas se concedió a Michel Mayor y Didier Queloz, “po
In 2012, the Frontiers of Knowledge Basic Sciences Award went to Michel Mayor and Didier Queloz “for their pathbreaking development of new astronomical instruments and experimental techniques that led to the observation of planets outside the solar system,” in the words of the committee’s citation.
This contribution facilitated “the discovery, in 1995, of a giant planet orbiting another star, which spawned a revolution in astronomy. Today, more than five hundred exoplanets are known and the first direct measurements of some of their atmospheres have been obtained,” the citation continued.
When they first started looking for planets around sun-like stars, few astrophysicists believed it was feasible to detect a small, dark object moving close to another – its star – of enormous size and brilliance. But the two men, whose discovery has now earned them a Nobel Prize in Physics, invented and developed a technique known as radial velocity, based on the Doppler effect, to detect such objects by indirect means. The technique works by examining the star’s light for tell-tale signs of changes in its movement caused by the gravitational pull between planet and star.
It is with this method that science has found most of the extrasolar planets catalogued to date. In addition, Mayor and Queloz were instrumental in developing HARPS, “the world’s leading planet discovery machine” as the committee called it; the most productive search tool based on their technique. The Swiss astrophysicists were also involved in developing the “transit method”, in which planets are spotted by the slight dimming of a star’s light as the orbiting body crosses its disk. It was this method that yielded the first detection of a rocky extrasolar planet.
The discovery that came “too fast”
On receiving the Frontiers Award, they looked back at their finding as one in a chain of tumultuous events. As Queloz described it: “At that time there were very few people looking for planets, and it was a kind of bizarre, weird project. We had built this really precise machine and thought it was going to take years to detect a signal. And then suddenly there it was! However, what we were observing didn’t fit with any known planet in the solar system. At first I thought I was mistaken. But Michel has the kind of mind that is ready for the unexpected, and that was essential to our success.”
Even so, Mayor decided it was best to wait until the star could be observed again, one year later. “In July 95 we repeated our measurements and got exactly the same signal,” recalled the new Frontiers laureate. “It was then we knew that we had really a planet.” The two scientists’ initial wariness had to do with the type of planet detected; with a mass similar to Jupiter but, unlike the gas giants of our solar system, circling just a short distance from its star. 51 Pegasi b – as they baptized it – has an orbit of just four days. As it turns out, this is true of the vast majority of planets detected since, but at the time, as Mayor related, “it was a huge surprise; we were saying ‘what is this?’”
After checking the measurements, they sent their findings to the journal Nature. Two of the three astrophysicists reviewing the paper recommended it for publication. The date set for it to appear was November 23, 1995, but that same October, Mayor and Queloz presented the results at a congress in Florence. The story was seized on by the press and, since then, extrasolar planets have rarely been out of the headlines: “The media attention was entirely unexpected,” remarked a bemused Mayor at the time. “It was only then we realized how important our work was for the general public.”
In his view, “the next goal is to understand the physics of the formation of these planets.” Though in the long term, “what really matters, the big, big challenge, is to understand if life is a common feature in the universe. I don’t know when we might know whether a given planet sustains life, because these are very difficult measurements that can probably only be done from space. But we also know that life affects the chemical composition of a planet’s atmosphere. I am sure space agencies will make this a priority objective.”
Nine Nobel Prize winners, previous laureates of the Frontiers Awards
The Nobel Prize in Physics awarded today to Mayor and Queloz boosts to nine the number of previous laureates of the Frontiers of Knowledge Awards who have gone on to win the recognition of the Swedish Academy: Shinya Yamanaka and James P. Allison, winners in the Biomedicine category of the awards, received the Nobel Prize in Medicine in 2012 and 2018 respectively, while Robert J. Lefkowitz, Frontiers laureate in Biomedicine, obtained the Chemistry Nobel in 2012. In Economics, Finance and Management, three Frontiers awardees have gone on to take the Nobel Memorial Prize in Economic Sciences: Lars Peter Hansen, Nobel laureate in 2013; Jean Tirole, in 2014, and Angus Deaton, in 2015. Finally, William Nordhaus followed up his Frontiers Award in Climate Change with the Nobel in Economics, both in 2018.