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Didier Queloz

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Didier Queloz is a prominent Swiss astronomer whose research has fundamentally changed our understanding of the cosmos. He is a central figure in the "exoplanet revolution," a period of massive discovery regarding worlds outside our solar system. Currently, he holds several prestigious positions. He is the Jacksonian Professor of Natural Philosophy at the University of Cambridge. He is also a fellow of Trinity College, Cambridge. Additionally, he serves as a professor of physics at ETH Zurich. His work spans many disciplines, including physics, chemistry, and biology.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

In 1995, Queloz and his doctoral advisor, Michel Mayor, made a landmark discovery. They identified 51 Pegasi b, which was the first exoplanet found orbiting a Sun-like star. This star is known as 51 Pegasi. The planet is classified as a "Hot Jupiter," meaning it is a giant planet that orbits very close to its star. To find this world, they used a method involving stellar radial velocity. This technique measures the small, periodic changes in a star's movement. These changes are caused by the gravitational pull of an orbiting planet.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

This detection was made possible through advanced technology and clever science. The team used a new type of spectrograph called ELODIE. This instrument was installed at the Haute-Provence Observatory. The spectrograph allowed them to observe the Doppler effect. The Doppler effect helps scientists detect the tiny wobbles in a star's velocity. Queloz also developed new algorithms to help separate planetary signals from stellar activity. This activity refers to natural changes on the star's surface that can look like a planet. His work in this area set the foundation for modern precision spectroscopy.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

Throughout his career, Queloz has led the development of many important astronomical tools. In 2000, he served as a project scientist for the development of HARPS. This is a high-precision spectrograph for the ESO 3.6m telescope. It was commissioned in 2003 and became a global standard for Doppler spectroscopy. He also led the installation of CORALIE on the 1.2-metre Leonhard Euler Telescope. These instruments allowed him to detect planets in the southern hemisphere. His work with these tools has led to the detection of hundreds of planets.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

Queloz has expanded his research to include transiting planets. A transit occurs when a planet passes directly in front of its star from our perspective. By combining transit data with radial velocity measurements, scientists can learn much more. They can measure both the mass and the radius of a planet. This allows them to calculate the bulk density, which is the planet's average density. Knowing the density helps scientists understand if a planet is rocky or gaseous. For example, he helped find the first planet with a density similar to a rocky planet, known as COROT-7b.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

His scientific achievements have earned him the highest honors in the world. In 2019, he was awarded the Nobel Prize in Physics. He shared this prize with Michel Mayor and Jim Peebles. The Nobel Committee recognized them for discovering an exoplanet orbiting a solar-type star. This discovery helped us understand the evolution of the universe. In 2017, he also received the Wolf Prize in Physics for his planet discoveries. Earlier, in 2011, he and Mayor won the BBVA Foundation Frontiers of Knowledge Award.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

Today, Queloz focuses on the search for life and habitability in the universe. He is the founding director of the Center for the Origin and Prevalence of Life at ETH Zurich. He also directs the Leverhulme Centre for Life in the Universe at Cambridge. This center brings together experts in astrophysics, chemistry, and biology. One of his major research areas is the "abiogenesis zone." This is a term describing the minimum conditions needed for the origins of RNA precursors on exoplanets. He is also involved in the CHEOPS space mission, which measures exoplanet radii.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek

His recent work includes studying the TRAPPIST-1 system, which is a very interesting planetary system. He also works on the SPECULOOS project to find Earth-sized planets around ultra-cool dwarf stars. Through the Terra Hunting Experiment, he uses the HARPS-3 spectrograph to look for Earth analogues. These are planets that are very similar to our own Earth. By studying these distant worlds, Queloz hopes to answer the biggest question of all: are we alone in the universe? His research connects the physics of stars to the very beginnings of life.

Mayor and Queloz Nobelweek
Mayor and Queloz Nobelweek
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