Nobel Prize for Physics reveal secrets of space
October 8, 2019
Among the staggering expanse of unknown in our universe, we humans, as well as other animals, stars and even planets unfathomably far away only make up 5% of matter that is known.
This year's Nobel Prize for physics recognized both the theory that gave us a concept of known and unknown matter, and the observation of a world beyond our own.
Three scientists — James Peebles, Michel Mayor and Didier Queloz — were awarded the prize on Tuesday for their discoveries about the evolution of the universe and our place within it. Half of the prize was awarded to Peeble for his theoretical mapping of our cosmos, and the other half to Swiss duo Mayor and Queloz for their discovery of the first planet outside our solar system.
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Theory: the evolution of the universe
Despite telling the Nobel press conference he began his career feeling "uneasy" in the field of cosmology, Peebles' theoretical framework — developed since the mid-1960s — forms the foundation of modern understandings of our universe.
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His realization that the faint microwave radiation that permeated the cosmos around 400,000 years after the Big Bang was key in mapping the evolution of the universe allowed him to discover new physical processes. The findings showed us that the make up of our universe could be divided into three separate categories.
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Dark energy, dark matter, and a cup of coffee
Humans, other animals, trees, stars and all the other things we can see and touch make up "normal matter" — which only constitutes 5% of the total mass energy density in our universe.
While there's still much more to be discovered about this mere fraction of mass, the other 95% is even less tangible.
Scientists refer to 25% of it as 'dark matter' — which cannot emit light, so cannot be seen, but does have a detectable gravitational force — and the remaining 70% as dark energy, which physicists understand to be a completely different component of the universe, and is thought to drive the expansion of the universe.
Ulf Danielsson from the Nobel Committee provided a useful analogy, comparing our universe to a cup of coffee: "mostly it's coffee, which is dark energy, then there's a fair amount of cream, which is dark matter and then there's a tiny bit of sugar — this is the ordinary matter, and this is what science has been all about for thousands of years — until now."
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Observation: planets outside our solar system
Michael Mayor and Didier Queloz have dedicated their life's work to what Danielsson terms "the sugar in the coffee cup" — the mere 5% of the universe's content that is known. Theory, after all, is, as Peebles said, "empty without observation."
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That led them, in 1995, to discover a world beyond our own — a giant, gas exoplanet, which is a planet outside our solar system, more than 50 light years away in the constellation of Pegasus. Half as heavy as Jupiter, and very close to its star, 51 Pegasi b has a scorching surface temperature of 1000 degrees Celsiuis.
Such a groundbreaking discovery was not without controversy, Rene Heller from the Max Planck Institute for Solar System Research, told DW. "For five years there was a debate about it. Are they really planets? Aren't they just low-mass stars?"
"The planet was so unusual, so different from anything we have in the solar system," Heller said.
Astronomers have since uncovered more than 4,000 exoplanets. Their findings "opened up a completely new field of research," says Heike Rauer, director of the institute of planetary research at the German Aerospace Center. "I thought, 'Finally!'," she said about the recognition of Mayor and Queloz's work.
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"The great discovery is the great diversity of planets out there: planets with elliptical orbits, gas planets very close to their stars, mini gas planets that aren't much bigger than Earth but made up of hydrogen, cold mini gas planets, planets orbiting completely different types of stars. All this diversity that we didn't expect," Rauer told DW.
A life's work
Born in 1935 and entering the field of astrophysics in 1964, James Peebles said he would be "hard pressed" to find among his many years of research a single greatest insight, saying his discoveries are cumulatively "a life's work."
"I never had a plan of great observation," he told the Royal Swedish Academy of Sciences over the phone after the announcement. "I could think of one or two things to do in cosmology, so I just kept going."
Upon being asked if he had any words of wisdom for young, aspiring scientists, Peebles had this to say: "You should enter it for the love of science. The awards are charming and appreciated, but you should enter science because you're fascinated by it."
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