Members of the Nobel Committee for Physics sit in front of a screen displaying the portraits of the winners. AFP

Canadian-American cosmologist James Peebles and Swiss scientists Michel Mayor and Didier Queloz won the 2019 Nobel Prize for Physics on Tuesday for revealing the wonder of the evolution of the universe and discovering planets orbiting distant suns.

Peebles, of Princeton University in the United States, was awarded half of the 9-million-Swedish-crown ($910,000) prize while Mayor and Queloz, from Switzerland's University of Geneva and Britain's Cambridge University, shared the rest.

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"This year's Nobel laureates have painted a picture of our universe far stranger and more wonderful than we could ever have imagined," Ulf Danielsson, a professor and member of the Nobel Committee for Physics, told reporters as the prize was announced.

The Royal Swedish Academy of Sciences said the scientists' research had "transformed our ideas about the cosmos".

Mayor and Queloz said it was "simply extraordinary" to be awarded a Nobel for what they described as "the most exciting discovery of our entire career".

Michel Mayor (right) and Didier Queloz pose for the photographer. File photo/AP

Peebles thanked the Nobel committee for the award but said his advice to young people wanting to go into science would be not to be lured by the prospect of such prizes.

"The awards and prizes, well, they are charming and very much appreciated, but...you should enter science because you are fascinated by it. That's what I did," he told reporters via telephone after the award announcement.

Physics is the second Nobel to be awarded this week; William Kaelin, Gregg Semenza and Peter Ratcliffe shared the medicine prize on Monday for discoveries about how cells respond to oxygen levels.

Among the Nobels, physics has often taken centre stage with winners featuring some of the greatest names in science like Albert Einstein, Marie Curie and Niels Bohr, as well as ground-breaking inventors such as radio pioneer Guglielmo Marconi.

James Peebles speaks at the 43rd annual Donald R. Hamilton Lecture, in Princeton, New Jersey. File photo/AP

Using theoretical tools and calculations, Peebles was able to interpret trace radiation from the infancy of the universe and so discover new physical processes, the academy said.

It said that Mayor and Queloz announced the first discovery of a planet outside our own solar system, a so-called "exoplanet", starting a revolution in astronomy. Over 4,000 exoplanets have since been found in the Milky Way.

"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," it said.

Reuters