Canadian-American cosmologist James Peebles and Swiss astronomers Michel Mayor and Didier Queloz on Tuesday won the Nobel Physics Prize for research that increases the understanding of our place in the universe. Peebles won one-half of the prize “for theoretical discoveries that have contributed to our understanding of how the universe evolved after the Big Bang,” professor Goran Hansson, secretary general of the Royal Swedish Academy of Sciences, told a press conference. Mayor and Queloz shared the other half for the first discovery, in October 1995, of a planet outside our solar system — an exoplanet — orbiting a solar-type star in the Milky Way. “Their discoveries have forever changed our conceptions of the world,” the jury said. Developed over two decades since the mid-1960s, Peebles’ theoretical framework is “the basis of our contemporary ideas about the Universe.” Peebles built upon Albert Einstein’s work on the origins of the Universe by looking back to the millenia immediately after the Big Bang, when light rays started to shoot outwards into space. Using theoretical tools and calculations, he drew a link between the temperature of the radiation emitted after the Big Bang and the amount of matter it created. His work showed that the matter known to us — such as stars, planets, and ourselves — only make up five percent, while the other 95 are made up of “unknown dark matter and dark energy.” “This is a mystery and a challenge to modern physics,” the academy said. Peebles is Albert Einstein Professor of Science at Princeton University in the United States, while Mayor and Queloz are both professors at the University of Geneva. Queloz also works at the University of Cambridge in Britain. Using custom-made instruments at their observatory in southern France in October 1995, Mayor and Queloz were able to detect a gaseous ball similar in size to Jupiter, orbiting a star around 50 light years from our own Sun. Harnessing a phenomenon known as the Doppler effect, which changes the color of light depending on whether an object is approaching or retreating from Earth, the pair proved the planet, known as 51 Pegasus b, was orbiting its star.