Nobel Prize in Physics – live blog

The Nobel Prize in Physics 2011 has been awarded to Saul Perlmutter, Brian P Schmidt and Adam G Riess for discovering the accelerating expansion of the universe
Nobel prize winning professors Adam Riess, Brian P. Schmidt and Saul Perlmutter
From left to right, Adam Riess, Brian Schmidt and Saul Perlmutter, who have won the 2011 Nobel Prize in Physics. Photograph: AP/EPA

10.22am: And so to day two of Nobel prize week and the pundits have been busy with their predictions as to who will be honoured with today's award for contributions to physics.

The Nobel Assembly is due to announce the winner, or winners, some time after 10.45am BST. We will follow events live here.

Yesterday, three scientists won the Nobel prize in medicine for groundbreaking work on the immune system. The award was overshadowed with the sad news that one of the recipients, Ralph Steinman at Rockefeller University in New York, passed away a few days ago. The Nobel assembly was unaware of this when the award was announced and has ruled that the prize will stand.

The prize earns the winner or winners 10 million Swedish kronor, or £934,000.

So who are the hot favourites for today's prize in physics?

According to the news agency Associated Press, physicists working on quantum entanglement – which underpins hopes for superfast quantum computing – are strong contenders for this year's prize.

Those predictions draw on names put forward by the citation company, Thomson Reuters, which failed to predict the winners of yesterday's prize.

Last year, the Nobel prize in physics was won by two Russian-born scientists, Andre Geim and Konstantin Novoselov at Manchester University, for their experiments with graphene, the strongest and thinnest material known.

Before becoming a Nobel prizewinner, Geim made headlines for levitating frogs, an achievement that earned him an Ig Nobel prize from the irreverent sister awards.

The potential of graphene-based products prompted the UK government to announce a £50m Global Research and Technology Hub to commercialise graphene products.

A live stream of the Nobel awards will appear here as soon as the video is available.

10.35am: Watch a video of the Nobel prize announcement here.

10.37am: There have been some regrettable Nobel awards in the past. Perhaps the most worrying was the award in 1949 to Dr Egas Moniz of Portugal for discovering the therapeutic value of lobotomy. The New England Journal of Medicine hailed the procedure as the birth of a "new psychiatry". The prize led to a rise in lobotomies, which were therapeutically worthless.

10.40am: As @simonfrantz points out on twitter, the last female Laureate in physics was Maria Goeppert-Mayer in 1963.

10.44am: From @Nobelprize_org on twitter: Facts: 188 individuals have received the #NobelPrize in #Physics since 1901, among them, 2 are women.

10.45am: More Nobel prize trivia from @Nobelprize_org on twitter: Marie Curie received the Nobel Prize in Physics in 1903 and Chemistry in 1911.

10.45am: The Nobel Prize in Physics 2011 goes to Saul Perlmutter, Brian P. Schmidt, Adam G. Riess

10.49am: From the Nobel Assembly:

What will be the final destiny of the Universe? Probably it will end in ice, if we are to believe this year's Nobel Laureates in Physics. They have studied several dozen exploding stars, called supernovae, and discovered that the Universe is expanding at an ever-accelerating rate. The discovery came as a complete surprise even to the Laureates themselves.

10.50am: The prize is for discovering the accelerating expansion of the universe.

Physics Nobel laureate Brian Schmidt US-born Brian Schmidt at the Australian National University in Canberra. Photograph: Ho/Reuters

10.51am: This explanation from the Nobel Assembly:

In 1998, cosmology was shaken at its foundations as two research teams presented their findings. Headed by Saul Perlmutter, one of the teams had set to work in 1988. Brian Schmidt headed another team, launched at the end of 1994, where Adam Riess was to play a crucial role.

The research teams raced to map the Universe by locating the most distant supernovae. More sophisticated telescopes on the ground and in space, as well as more powerful computers and new digital imaging sensors (CCD, Nobel Prize in Physics in 2009), opened the possibility in the 1990s to add more pieces to the cosmological puzzle.

The teams used a particular kind of supernova, called type Ia supernova. It is an explosion of an old compact star that is as heavy as the Sun but as small as the Earth. A single such supernova can emit as much light as a whole galaxy. All in all, the two research teams found over 50 distant supernovae whose light was weaker than expected - this was a sign that the expansion of the Universe was accelerating. The potential pitfalls had been numerous, and the scientists found reassurance in the fact that both groups had reached the same astonishing conclusion.

For almost a century, the Universe has been known to be expanding as a consequence of the Big Bang about 14 billion years ago. However, the discovery that this expansion is accelerating is astounding. If the expansion will continue to speed up the Universe will end in ice.

The acceleration is thought to be driven by dark energy, but what that dark energy is remains an enigma - perhaps the greatest in physics today. What is known is that dark energy constitutes about three quarters of the Universe. Therefore the findings of the 2011 Nobel Laureates in Physics have helped to unveil a Universe that to a large extent is unknown to science. And everything is possible again.

10.53am: One half of the prize goes to Saul Perlmutter at the Supernova Cosmology Project, Lawrence Berkeley National Laboratory and University of California, Berkeley, California.

The other half goes jointly to Brian Schmidt of the High-z Supernova Search Team at the Australian National University and Adam G. Riess at The High-z Supernova Search Team at Johns Hopkins University and Space Telescope Science Institute, Baltimore.

10.54am: All three are relative youngsters for the Nobel prize. Perlmutter was born in 1959, Schmidt in 1967 and Riess in 1969.

10.57am: More from the Nobel Assembly's material:

The growing rate of the expansion implies that the Universe is being pushed apart by an unknown form of energy embedded in the fabric of space. This dark energy makes up a large part of the Universe, more than 70 %, and it is an enigma, perhaps the greatest in physics today. No wonder, then, that cosmology was shaken at its foundations when two different research groups presented similar results in 1998.

11.02am: Nobel prizewinner Brian Schmidt answering questions:

"It feels like when my children were born … "

11.04am: Brian Schmidt:

"It seemed too crazy to be right so we were a little scared.

"I always look to Einstein because he got a lot right. Einstein's idea that space itself has an energy is the simplest reason that the universe could be speeding up."

11.23am: There are some wonderful videos of today's Nobel prizewinners discussing their work on the expansion of the universe.

Above is Brian Schmidt at the Australian National University speaking in 2009.

11.30am: Here, among others, is Saul Perlmutter speaking on the hidden universe in 2009.

11.31am: Here is Adam Riess discussing his work at Johns Hopkins University in Maryland.

11.44am: Some of my requests for thoughts on today's Nobel prize in physics have begun to arrive. Here is what Professor Pedro Ferreira, a cosmologist at Oxford University, has to say:

I think this is wonderful news! You have to put this into perspective. Only few decades ago, cosmology was exciting, but quite esoteric. People could make stuff up and get away with it. Now, because of endeavours such as the supernovae observations, we can make hard, accurate statements about the Cosmos, we can really say precise things about the state of the Universe. And it is only going to get better. It is a truly great time to be working in the field.

11.59am: Professor Sir Peter Knight, president of the Institute of Physics, said:

The recipients of today's award are at the frontier of modern astrophysics and have triggered an enormous amount of research on dark energy.

These researchers have opened our eyes to the true nature of our universe. They are very well-deserved recipients.

Physics Nobel laureate Saul Perlmutter Saul Perlmutter receives the official phone call from the Royal Swedish Academy at his home in Berkeley, California. Photograph: Paul Sakuma/AP

12.10pm: More reaction is coming in from scientists in the field. Dr Mark Sullivan, another Oxford physicist, adds:

I think this is fantastic news, and thoroughly well-deserved. Their direct discovery of the accelerating universe in the late 1990s, using distant cosmic explosions known as supernovae, has rewritten textbooks, and was one of the landmark breakthroughs of 20th Century physics. The nature of the dark energy that propels this accelerating universe remains a mystery, preoccupying physicists ever since, and is at the forefront of modern astrophysical research - it's the motivation for many ongoing, and future, ground and space-based experiments.

12.22pm: David Pendlebury from Thomson Reuters, who predict the winners every year, has been in touch.

He says we may like to know that: "Regarding yesterday's Nobel Prize in Physiology or Medicine, Beutler and Hoffman were selected as Thomson Reuters Citation Laureates in 2008, and Steinman was chosen in 2010."

And on today's Nobel prize in Physics, he says all three winners were selected as Thomson Reuters Citation Laureates in 2010.

12.43pm: Some thoughts from Lord Martin Rees, Astronomer Royal and emeritus professor of cosmology and astrophysics at the University of Cambridge:

This award recognises an important and surprising discovery. Even empty space contains energy and exerts a kind of 'antigravity' which causes cosmic expansion to accelerate. It will be a long time before theorists understand this force -- it is part of the bedrock nature of space and time. This discovery has been subsequently strengthened and corroborated by other advances: the evidence from the cosmic microwave background (especially the Boomerang and WMAP experiments) that the geometry of the universe is 'flat', and an accumulation of evidence from observations with large telescopes that atoms and 'dark matter' amount to no more than 30 percent of density needed to make it so.

I think, however, that this is one of the increasingly frequent instances when the Nobel Committee is damagingly constrained by its tradition that a prize can't be shared between more than three individuals. The key papers recognised by this award were authored by two groups, each containing a dozen or so scientists. It would have been fairer, and would send a less distorted message about how this kind of science is actually done, if the award had been made collectively to all members of the two groups.

Adam Riess celebrates winning the 2011 Nobel Prize in Physics Adam Riess celebrates his win. Photograph: Michael Reynolds/EPA

3.10pm: Michael Rowan-Robinson, professor of astrophysics at Imperial College London, has summed up the discovery's significance:

I have a particular interest as I was part of a group that looked for other reasons to explain how the universe can appear to be expanding at an ever-faster rate. We were unable to undermine the findings of the two teams and it's now momentous to see the research which indicated the existence of dark energy being rewarded so prestigiously.

These astrophysicists' research revolutionised our common perception of the universe and unveiled an array of mysteries that we are still trying to fathom.

3.18pm: Professor Carlos Frenk, director of the Institute for Computational Cosmology at Durham University, said today's prize recognises "one of the most unexpected and dramatic discoveries in physics in recent decades":

It is dramatic because it implies that we do not inhabit a simple, elegant universe made only of matter but a universe that, in addition to matter, contains a strange substance, so bizarre that we call it "dark energy".

We have no idea of what the dark energy revealed by the supernovae data is – unravelling its identity ranks as one the great scientific challenges of the 21st century.

3.33pm: "Nobody really knows what it is that has been discovered," says Peter Coles, an astrophysicist at Cardiff University, in Nature.

3.45pm: Nobelprize.org has a telephone interview with Adam Riess, recorded shortly after he was told he had won the Nobel Prize in Physics. He says of the moment he realised his data were showing the expansion of the universe was accelerating: "I remember thinking, I've made a terrible mistake and I have to find this mistake."

5.26pm: Read the Guardian's take on the story, with reaction from leading physicists and the prizewinners.

6.07pm: Robert Kirshner from Harvard University, who supervised Schmidt and Riess when they were PhD students, quoted by Physics World, welcomed the decision by the Nobel committee:

We did a lot of foundational work at Harvard and my postdocs and students made up a hefty chunk of the High-Z Team … [Riess] did a lot after the initial result to show that there was no sneaky effect due to dust absorption and that, if you look far enough into the past, you could see that the universe was slowing down before the dark energy got the upper hand, about five billion years ago.

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