Scitech | 2011 Nobel Prizes – Physics: written in the stars

Physics: written in the stars

Almost 150 years ago Alfred Nobel patented dynamite – a mixture of nitroglycerin and an inert substance (like dirt). This invention amassed him a fortune. Years later, when his brother died, a French newspaper erroneously published Nobel’s own obituary, calling him a “merchant of death.” Worried about his legacy and potentially plagued with guilt, Nobel donated the majority of his estate to the creation of the Nobel Prizes after his death. Each year, the Nobel Prize committee gathers together to choose laureates for physics, chemistry, physiology or medicine, literature, and peace. Astute readers may wonder why there is no Nobel Prize for math – legend has it that  Nobel never got over the fact that a mathmatician stole away one of his lovers.

 

The 2011 Nobel Prize for Physics has been jointly awarded to American scientists Saul Perlmutter, Brian P. Schmidt, and Adam G. Riess for observing distant supernovae and proving the expansion of the universe.  One half of the Nobel Prize was awarded to Perlmutter, and the other half to Schmidt and Riess. Perlmutter is now a professor of Physics at UC Berkeley, where he heads the multinational Supernova Cosmology Project.  Both Riess and Schmidt are members of the High-z Supernova Search Team, which spans multiple countries and uses supernova to chart the expansion of the universe.

The three scientists were awarded the Nobel Prize “for the discovery of the accelerating expansion of the universe through observations of distant supernovae,” according to the Nobel Prize press release. They used type 1a supernovae, which result from the explosion of white dwarves, to measure the rate of the universe’s growth since the conjectured Big Bang, which is estimated to have occurred nearly 14 billion years ago.  A supernova is essentially an energetic and luminous star explosion that causes a burst of radiation.  There are different types of supernovae, and they are categorized according to the composition of the light emitted.  In type 1a supernovae, the light breakdown lacks hydrogen. Because hydrogen is usually a primary fuel source of stars, if it has no hydrogen, then we know the star has completely used up all of its existing fuel.

Perlmutter, Schmidt and Riess actually made their discoveries in 1998, but the corroboration of their evidence was not completed until recently.  Both research teams separately came to the same conclusion and had identical results after years of observing and cataloguing type 1a supernovae.  The scientists wanted to find out what is going to happen to universe in the future.  Their results show evidence that the universe is spreading apart and accelerating due to the forces of “dark energy”, indicating that the future of the universe is, essentially, a cold, dark void.

This proposed “dark energy” is deduced from the ever-increasing expansion of the universe. Since gravity would cause ordinary and dark matter – matter that does not emit or scatter light – to decelerate, a new type of energy had to be hypothesized – that is dark energy. The confirmation of dark energy’s existence is the corollary of confirmation of the universe’s accelerating expansion and it was this discovery that the Nobel Prize was awarded for. This may not seem like an extremely applicable or practical accomplishment, but dark energy appears to constitute about 75 per cent of the mass of the entire universe.  As a result this discovery is extremely important to our understanding of the nature of the universe.


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