MATTER Magazine: Nobel Prize in Physics

How has the universe evolved? What is our planet’s place in the cosmos? On Oct. 8, three physicists who have grappled with these questions received the Nobel Prize for their research. Half of the award was given to James Peebles, the sitting Albert Einstein Professor of Science at Princeton University, for his work with essential theoretical frameworks and models in the field of cosmology since the mid-1960s. The other half was given to both Michel Mayor and Didier Queloz, researchers at the University of Geneva in Switzerland for their groundbreaking “discovery of an exoplanet orbiting a sun-like star” in the 1990s.Back in the 1960s, cosmology, the study of the origin and evolution of the universe, was a newer contender in the realm of astronomy. Models of an expanding universe and the Big Bang theory existed, but there was a lack of connection between the theoretical and experimental analysis. That changed in 1965 when Arno Penzias and Robert Wilson discovered the Cosmic Microwave Background (CMB): a light source that was measured to be emitted when the universe was just 380,000 years old. Peebles used this intriguing source of energy to help support the Big Bang model of the Universe. From the present energy of the photons from CMB, he and a few colleagues inferred temperatures up to the magnitude of 1010 in degrees Celsius. Not only that, but Peebles also made innovative calculations in Big Bang nucleosynthesis: the study of materials created between protons and neutrons during the explosively-hot, early stages of the universe. He ultimately concluded that only five percent of the universe is known while the other 95 percent is consumed by the mysterious concepts of dark matter and dark energy.Peebles contributed even more to the field of cosmology in the 1970s by developing cosmic structure formation. From the different thermal patterns in the CMB, Peebles developed theoretical frameworks that could predict where galaxies would develop. He continued to make developments in almost every major theory of cosmology: cosmic inflation, models of dark matter (cold dark matter) and understanding dark energy. In all, he can be quoted as “laying the foundation for all modern investigations in cosmology, both theoretical and observational.” Without his work, our current knowledge of the whole universe would be greatly depleted.Today we see exoplanets—planets that orbit other stars—being observed regularly around the sun. But in the 1990s, astronomers were struggling, fruitlessly searching for years for these unobservable exoplanets until Mayor and Queloz came along. To detect such a planet, astronomers had to measure miniscule shifts in light, caused by the exoplanet’s star. With the help of a custom-built device, they could detect the light from 142 stars at once to hasten their search. In October 1995, they discovered the first exoplanet ever to orbit a sun-like star in the constellation Pegasus. Their discovery jump started the current database of over 4,000 exoplanets found (just in the Milky Way) that have forced theoretical physicists and astronomers alike to research and reconsider why certain planetary systems exist. Eventually, through the initial discovery of Mayor and Queloz, we can hope to capitalize on answering the ever-looming question of the possibility of other life in the universe.For a more detailed look into the work of the Noble winners, they will each be speaking during a two-hour Nobel Lecture in December of this year. Although both of these discoveries seem to have been in the distant past, both have been fundamental in our current look at both the past and present of our universe. What other secrets will we pull from the universe’s expanse?