Dear friends,
It has been a long time since my last newsletter. My service as department chair ended on June 30, and I immediately returned to doing science and writing grant proposals. During sabbatical quarters this Fall and Winter, I am also learning new skills, such as machine learning techniques to assist with our search. I will return to teaching in Spring 2020 to teach the fifth edition of the UCLA SETI course.
This week, the U.S. Senate's Committee on Commerce, Science, and Transportation introduced the NASA Authorization Act of 2019. The Act provides that: "the [NASA] Administrator shall support activities to search for and analyze technosignatures." It remains to be seen whether the language will survive the markup, reconciliation, and voting processes in Congress and become law, but it's an encouraging development.
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In other news, a Nobel prize rewarded the game-changing discovery of exoplanets. The 2019 Nobel Prize in Physics was awarded to two Swiss astronomers who, 24 years ago, reported the discovery of an exoplanet orbiting a Sun-like star. The 1995 report by Michel Mayor and Didier Queloz was astonishing: a planet roughly 150 times Earth's mass circles its host star at the puny distance of 5 million miles, roughly 20 times closer than Earth's orbit around the Sun. The existence of such a massive planet so close to its star perplexed scientists. It defied our understanding of how planets form. The evidence forced us to revise models of planet formation, and the discovery was bound for the history books. But the impact of the discovery went well beyond the concerns of planetary astronomers and touched everyone who has ever contemplated his or her place in the cosmos.
The host star, 51 Pegasi, is located in our cosmic neighborhood, only 50 light years away. At the time of Mayor and Queloz's discovery, the number of planets in the Milky Way Galaxy was anyone's guess, and some argued that Earth-like environments were rare. But the existence of a planetary system so close to the Sun suggested that planets might be ubiquitous. Today, we know that there are more planets than stars in the Galaxy, and a sizeable fraction of these planets have temperatures suitable for the existence of liquid water and life. The naive picture that we inhabit a unique world in an otherwise lifeless cosmos has been overturned. Instead, the abundance of exoplanets suggests that our universe may in fact be teeming with life.
With the existence of exoplanets firmly established, science and funding priorities evolved. In 2009, NASA launched the Kepler space telescope with the goal of counting exoplanets and detecting Earth-size planets in a small region of the sky. This wildly successful mission was the brain child of NASA Ames scientist William Borucki, who worked on the problem for over 30 years starting in 1984 and whose proposals to detect exoplanets with a space telescope had previously been rejected by NASA four times between 1992 and 1998. Borucki persevered and his fifth proposal was selected. Whereas Mayor and Queloz's Doppler technique detects planets by observing periodic changes in the velocities of the host stars, Borucki's transit technique detects planets that obscure some of the host star’s light once per orbit.
The Kepler telescope ushered in a Copernican-style revolution. Its continuous observations of more than 100,000 stars between 2009 and 2013 revealed the existence of thousands of exoplanets. Extending the Kepler discovery statistics to the rest of the Galaxy, we can now confidently predict that the Milky Way harbors billions of Earth-size planets. Our home planet, although special to us, is nothing special in the cosmos. The prospects for the existence of life, and perhaps intelligent life, are greatly enhanced by the abundance of exoplanets. This realization has accelerated the search for life in the universe, with new programs designed to search for biosignatures (evidence of biological activity) or technosignatures (evidence of technological activity).
Mayor and Queloz are truly deserving of the Nobel Prize. Their discovery changed our understanding of how planets form, suggested that planets may be ubiquitous, and transformed the funding landscape for the search for exoplanets. But Borucki would have been an equally deserving prize recipient. The combined work of Mayor, Queloz, and Borucki revolutionized how we view ourselves in the cosmos. Humanity's quest for cosmic companionship is no longer wishful thinking but is now solidly grounded in evidence.
The recognition of the importance of exoplanets by the Nobel Committee would surely have pleased Carl Sagan, who was born 85 years ago today. Carl was an inspiration to many and a strong proponent of the search for technosignatures.
Warm regards,
Jean-Luc Margot
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