The Nobel Prize in Physics has been awarded to James Peebles, Michel Mayor and Didier Queloz for "furthering our understanding of the universe and our place in it."
Mayor and Queloz, both from Switzerland, and Peebles, who is Canadian-American, received the prize at a ceremony in Stockholm, Sweden, on October 8.
Speaking to the ceremony via video call, Peebles, whose work covers the origins of galaxies, said that the notion of dark matter was introduced by Albert Einstein in 1917 but still remained a mystery to us.
Peebles used theoretical tools and calculations to demonstrate that just five per cent of content in the universe is known, including matter such as stars, planets, trees and humankind.
"The rest, 95 per cent, is unknown dark matter and dark energy. This is a mystery and a challenge to modern physics," the Nobel committee said in a statement.
Asked by a journalist about whether there was life on other planets, Peebles said that we could be sure that even if there was, humans would never be able to see it.
Mayor and Queloz were honoured for the discovery of a exoplanet orbiting a solar-type star in 1995 at the Haute-Provence Observatory in southern France.
Called 51 Pegasi b, the planet is a gaseous ball comparable to the solar system's biggest gas giant, Jupiter.
"Their discoveries have forever changed our conceptions of the world," the Nobel committee said.