The Royal Swedish Academy of Science announced today the Nobel Prize in Physics for 2011, something that made us at the Oskar Klein Centre very proud indeed. The Prize goes to the two teams who discovered the present acceleration of the universe using supernovae as standard candles: the Supernovae Cosmology Project, in the person of Saul Perlmutter, and The High-z Supernova Search Team in the persons of Adam G. Riess and Brian P. Schmidt.
Ariel Goobar, professor at the Oskar Klein Centre, has been part of the Supernovae Cosmology Project since its beginning, when directly after his PhD defense in 1991, started a PostDoc at the LBL with Saul Perlmutter.
– I left particle physics to work on a murky field that nobody thought made any sense. says Ariel Goobar – I have worked with Saul in this project for almost 20 years now, it feels great to have been part of this journey from the very bumpy beginning when nobody thought these measurements were possible to do, until today’s monumental recognition.
Supernovae are some of the most powerful explosions in the universe, making these objects visible over very large distances. One special type of supernovae, type Ia, appears to always explode with the same brightness which makes it possible to determine their distances.
By doing this for many supernovae scientists discovered that the objects were fainter, that is much more distant, than what was possible in a Universe that only contains matter. Instead of slowing down, the expansion of the Universe is accelerating. A previously unknown force, often referred to as “dark energy”, seem to push the galaxies apart. By combining different measurement techniques it appears that the “dark energy” accounts for about 70% of the total energy density of the universe. says Rahman Amanullah, a researcher at the Oskar Klein Center working in the field together with Ariel.
Jesper Sollerman, from the Department of Astronomy, worked instead with the other team (the High-z Supernova Search Team, including Riess and Schmidt) for many years, and have since continued to collaborate with these researchers in more recent projects.
– It is fantastic that this work now got this recognition, says Sollerman. Of course we knew these measurements were important – thay have more or less overthrown cosmology the past 15 years. But it is also brave of the Noble committee to award this study, as we still do not really understand the cause of the cosmic acceleration.
The Oskar Klein Centre is still involved in some of the main international projects investigating the nature of Dark Energy, and surely more exciting time are ahead us.