The two areas of research, cosmology and exoplanets, “really, sort of tell us something very essential — existential — about our place in the universe,” Ulf Danielsson, theoretical physicist and a member of the Nobel Prize committee that selected the winners, said during an online broadcast.
The Nobel Prize in Physics 2019 was awarded “for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos” with one half to James Peebles “for theoretical discoveries in physical cosmology”, the other half jointly to Michel Mayor and Didier Queloz “for the discovery of an exoplanet orbiting a solar-type star.”
The Royal Swedish Academy of Sciences has decided to award the Nobel Prize in Physics 2019 “for contributions to our understanding of the evolution of the universe and Earth’s place in the cosmos” with one half to James Peebles at Princeton University “for theoretical discoveries in physical cosmology” and the other half jointly to Michel Mayor University of Geneva, Switzerland and Didier Queloz with University of Geneva and University of Cambridge “for the discovery of an exoplanet orbiting a solar-type star”
New perspectives on our place in the universe
This year’s Nobel Prize in Physics rewards new understanding of the universe’s structure and history, and the first discovery of a planet orbiting a solar-type star outside our solar system.
James Peebles’ insights into physical cosmology have enriched the entire field of research and laid a foundation for the transformation of cosmology over the last fifty years, from speculation to science. His theoretical framework, developed since the mid-1960s, is the basis of our contemporary ideas about the universe.
“I have been working in cosmology for 55 years,” he said in an interview. “I’m the last man standing, so to speak, from those early days.”
The Big Bang model describes the universe from its very first moments, almost 14 billion years ago, when it was extremely hot and dense. Since then, the universe has been expanding, becoming larger and colder. Barely 400,000 years after the Big Bang, the universe became transparent and light rays were able to travel through space. Even today, this ancient radiation is all around us and, coded into it, many of the universe’s secrets are hiding. Using his theoretical tools and calculations, James Peebles was able to interpret these traces from the infancy of the universe and discover new physical processes.
“There were bits of evidence,” he said. “But they were sparse and scanty and not nearly enough to convince me that we had the right general idea.”
The results showed us a universe in which just five per cent of its content is known, the matter which constitutes stars, planets, trees – and us. The rest, 95 per cent, is unknown dark matter and dark energy. Peebles noted that much of the universe remains mysterious. Scientists have yet to identify what makes up dark matter or dark energy.
The Exoplanet Revolution
In October 1995, Michel Mayor and Didier Queloz announced the first discovery of a planet outside our solar system, an exoplanet, orbiting a solar-type star in our home galaxy, the Milky Way. At the Haute-Provence Observatory in southern France, using custom-made instruments, they were able to see planet 51 Pegasi b, a gaseous ball comparable with the solar system’s biggest gas giant, Jupiter.
At the time of the discovery, some astronomers had begun to wonder if they would ever find planets. “Maybe most stars don’t form with planets and our solar system is unusual and life is incredibly rare,” said Debra A. Fischer, a professor of astronomy at Yale. “Completely transformative,” Fischer said of the epic discovery. “We are the middle of a scientific revolution that people won’t appreciate until a hundred years go by.”
This discovery started a revolution in astronomy and over 4,000 exoplanets have since been found in the Milky Way. Strange new worlds are still being discovered, with an incredible wealth of sizes, forms and orbits. They challenge our preconceived ideas about planetary systems and are forcing scientists to revise their theories of the physical processes behind the origins of planets. With numerous projects planned to start searching for exoplanets, we may eventually find an answer to the eternal question of whether other life is out there.
Image at top of page: ESO Observatories, Chile