Speakers


Brian Schmidt

Nobel Prize in Physics

2011

For about a century, scientists have known that the universe is expanding, with its stars and galaxies moving away from one another. In 2011, however, Professor Brian Schmidt and two other scientists were awarded the Nobel Prize in Physics for their discovery in 1998 that the universe is not just expanding, but doing so at an accelerating rate. 

“Until recently, the majority of astrophysicists believed that the expansion of the universe would slowly wane, due to the effect of opposing gravitational forces. The discovery that the universe is expanding at an ever-accelerating rate came as a complete surprise to even the laureates themselves,” said the Nobel Prize committee in its citation. 

“In 1998, cosmology was shaken at its foundations when they presented their findings. If the expansion continues to speed up, the universe will end in ice,” the committee continued. 

For his PhD thesis, Professor Schmidt had mapped type II supernovae, which are exploding stars that can give off as much light as an entire galaxy, to measure the Hubble Constant, which is the accepted rate of the expansion of the universe. 

When he continued this work with other scientists on a different type of exploding star, a type 1a supernova, including his eventual fellow Nobel Laureate Professor Adam Riess, however, they noticed something odd: the light emitted by the distant supernovae was weaker than expected. Since light emitted by stars appears weaker from a larger distance, this was a sign that the universe’s expansion was accelerating.

At the time, another scientist, Professor Saul Perlmutter, was pursuing the same research with his own team and had made the same findings. Between them, the two teams found more than 50 supernovae whose light was dimmer than expected. Professor Perlmutter shared the 2011 Nobel Prize in Physics with Professors Schmidt and Riess.  

Professor Schmidt has said of his own team’s work: “It seemed too crazy to be right, so we were a little scared. But to my surprise, the accelerating universe was received by the scientific community more warmly than I expected. This was probably partially due to the fact that two highly competitive teams had arrived independently at the same answer.” 

Since Professor Schmidt’s discovery, many other scientists have scrutinised the accelerating universe. Professor Schmidt himself has continued to look to the stars. Alongside other scientists at the Australian National University, where he is Vice-Chancellor, he is helping to create the first comprehensive digital survey of the entire southern sky. 

The project, which utilises a state-of-the-art telescope called the SkyMapper, will produce a massively detailed record of more than a billion stars and galaxies, to a sensitivity one million times fainter than the human eye can see. The data will enable astronomers to map the invisible material known as dark matter, uncover the first quasars and stars to form in the universe, and discover new dwarf galaxies, among other things.