In his will, Alfred Nobel specified five areas for which awards should be given. These are physics, chemistry, medicine, literature and the promotion of peace. It is easy to see that astronomy is not on this list. That’s why Edwin Hubble spent most of the last years of his career trying to make astronomy a subdivision of physics in the hope that the Nobel Committee would start recognising the achievements of astronomers.
But although Hubble himself never won the Nobel Prize, his efforts were not in vain. Shortly after his death, the Nobel Committee changed the criteria for the physics prize to include astronomy. In honour of Nobel Day, which is celebrated on 10 December, we would like to tell you about six of the most important astronomical discoveries that have been awarded the Nobel Prize.
Discovery of pulsars (1974)
The 1974 Nobel Prize in Physics was shared by Antony Hewish and Martin Ryle. Ryle received it for his revolutionary developments in radio astronomy, which changed the field forever. Hewish was awarded the prize for his discovery of pulsars, which became one of the most important events in the history of modern astronomy.
It should be said that this decision of the Nobel Committee was often criticised later. And not because the discovery was not so important. The fact is that the discovery of pulsars was actually made by astronomer Jocelyn Bell, who worked in Hewish’s group and convinced him to continue researching unusual signals, while he believed that they were of terrestrial origin. But the Royal Swedish Academy of Sciences decided to follow the formal approach, according to which all the credit for a discovery goes to the supervisor. So Bell was left without an award.
Discovery of microwave relic radiation (1978)
The 1978 Nobel Prize in Physics went to three scientists: Pyotr Kapitsa, Arno Penzias and Robert Wilson. Kapitsa received it for his work in low temperature physics. But Penzias and Wilson were awarded for one of the most fundamental astronomical discoveries of the 20th century. They were able to detect microwave relic radiation, a kind of ‘echo’ left over from the Big Bang.
The discovery itself was made in 1964. Interestingly, Penzias and Wilson did not intend to search for relict radiation. They had assembled the antenna for the purpose of experiments in radio astronomy and satellite communications. However, during calibration, it turned out that the antenna had an excess noise temperature of 4.2 degrees. Penzias and Wilson could not understand what was causing the interference for a long time, until their colleagues told them about relict radiation, the existence of which had previously been predicted by some cosmological theories.
Discovery of the accelerated expansion of the Universe (2011)
Scientists have known that our Universe is expanding since the late 1920s. For a long time, however, it was assumed that this expansion was slowing down. That all changed in the late 1990s, when research teams led by Saul Perlmutter, Brian Schmidt and Adam Riess measured supernovae in distant galaxies. It turned out that they were less bright than expected. In turn, this meant that the real distance to these galaxies was greater than the distance calculated on the basis of the previously established value of the Hubble parameter.
Therefore, it was concluded that the Universe is not just expanding, but is expanding with acceleration. An unknown type of energy with negative pressure, called dark energy, is responsible for this acceleration. Of course, the Nobel Committee could not miss such a fundamental discovery. In 2011, Perlmutter, Schmidt, and Riess shared the physics prize.
Observations of gravitational waves (2017)
The first indirect evidence of the existence of gravitational waves was obtained in 1974 through the observation of a close system of two neutron stars PSR B1913+16. For this discovery, scientists Russell Hulse and Joseph Taylor received the Nobel Prize in Physics in 1993.
The first real registration of gravitational waves took place in 2015 with the detectors of the LIGO Gravitational-Wave Observatory. They were generated by the fusion of two stellar mass black holes. The Swedish Royal Academy of Sciences was quick to recognise this achievement. Already in 2017, it honoured Rainer Weiss, Barry Barish and Kip Thorne for their decisive contribution to the creation of LIGO and the first-ever direct observation of gravitational waves.
Discovery of exoplanets (2019)
Many generations of scientists have dreamed of discovering extrasolar worlds. Some astronomers even claimed to have solved this problem, but later such statements were not confirmed. Swiss scientists Michel Mayor and Didier Queloz made history. In 1995, they managed to prove that the fluctuations in the radial velocity of the sun-like star 51 Pegasi were caused by a gas giant in close orbit around it.
This discovery opened a new page in the history of astronomy. Since then, scientists have been able to confirm the existence of almost six thousand extrasolar worlds. As for Michel Mayor and Didier Queloz, they received their well-deserved Nobel Prize in 2019.
Discovery of a black hole in the centre of the Milky Way (2020)
The latest Nobel Prize for astronomical discovery was awarded in 2020. It was shared by Roger Penrose, Reinhard Genzel, and Andrea Ghez. Penrose was awarded it for his work in the field of black holes. In 1965, he managed to prove that black holes can indeed form and described them in detail. His groundbreaking paper is still considered the most important contribution to general relativity since Einstein.
As for Genzel and Ghez, in the 1990s they led groups of astronomers who observed the orbits of the stars in the centre of the Milky Way. Independently of each other, they managed to prove that there is a supermassive compact object in the Milky Way whose gravity affects the trajectories of all celestial bodies in its vicinity. In 2022, the Event Horizon Telescope collaboration published the first-ever image of the object’s silhouette, confirming that it is indeed a supermassive black hole.
