A nontechnical talk by Dr. Robert Kirshner, Jan 28, 2026.

One hundred years ago, Edwin Hubble showed that the universe is expanding. In the 1990s, astronomers found that the expansion is not slowing down, as expected, but speeding up. This led to a Nobel Prize in Physics (for our speaker's students) and a consensus that we live in a universe that is made up of invisible dark matter, mysterious dark energy, and only a pinch of the atoms we, and everything we can see in the Universe, are made of. Dr. Kirshner explains this history in everyday language and reviews recent observations indicate that even this picture may be too simple to account for all the evidence. He also discusses the status of building the largest telescopes ever planned in Earth's Northern and Southern hemispheres. 

Robert Kirshner is Emeritus Professor of astronomy at Harvard and Research Professor at the California Institute of Technology. He was the Head of Science at the Gordon and Betty Moore Foundation, and now serves as the Executive Director of the Thirty-Meter Telescope International Observatory.  

Dr. Alfonso Davila (NASA Ames Research Center)

Nov. 24, 2025

In 2005, NASA's Cassini spacecraft made a groundbreaking discovery—it found massive plumes of ice and gas erupting from the south pole of Enceladus, a small but geologically-active moon of Saturn. These plumes are now believed to originate from a subsurface ocean of liquid water beneath the moon’s icy crust, with conditions compatible with life, as we know it. The talk focuses on our current understanding of Enceladus' plume and subsurface ocean, and on past and future strategies to search in them for possible evidence of life. 
 
Alfonso Davila is a Research Scientist in the Exobiology branch at NASA Ames Research Center, where he helps develop strategies to search for evidence of life beyond Earth.

With Dr. Roger Romani (Stanford University):
NASA's Fermi Gamma-ray Space Telescope has revealed a violent high-energy universe full of stellar explosions, black hole jets, and pulsing stars.  These cosmic objects are often faint when observed with visible light, but glow bright with gamma rays.   Dr. Romani describes the quest to discover the true nature of the most puzzling of these gamma-ray sources.  Several turn out to be a kind of bizarre star corpse called a 'black widow' pulsar -- where a dead star has a companion that it is slowly destroying.
This is a talk from 2014, but it is still relevant today.

Presenter is the Project Scientist, Dr. Robert Pappalardo (JPL)
May 22, 2024

Jupiter's moon Europa may be a habitable world, containing the “ingredients” necessary for life within its ocean. Data from NASA’s earlier Galileo mission suggest that a global, salty ocean exists beneath the icy surface. Tides have broken that floating ice shell to create impressive ridges, bands, and chaotic terrains. The Europa Clipper mission will explore Europa with a suite of instruments, through multiple close flybys from Jupiter orbit, examining the moon’s ice shell, ocean, and geology.  And it will search for current activity –including plumes that emerge from surface cracks. Dr. Pappalardo, the mission's Project Scientist, summarizes our understanding of Europa and the and status and promise of the Europa Clipper.

Apr. 17, 2024
In this talk, physicist and popular author Paul Halpern (St. Joseph's College) examines the history of the concept of a multiverse in science, and discusses the ideas by Einstein and other noted physicists that have led scientist today to take the notion of multiple universes seriously.  He also contrasts the scientific view of a multiverse to the picture we get in popular culture (think Marvel movies) and notes how significantly the two differ.  Dr. Halpern is the author of a new popular-level book also called "The Allure of the Multiverse" and many other nontechnical science books.

With Dr. Leonard Susskind (Stanford University)
Black holes, the collapsed remnants of the largest stars, provide a remarkable laboratory where the frontier concepts of our understanding of nature are tested at their extreme limits. For more than two decades, Professor Susskind and a Dutch colleague had a running battle with Stephen Hawking about the implications of black hole theory for our understanding of reality — a battle that he has described in his well-reviewed book The Black Hole Wars. In this talk Dr. Susskind tells the story of these wars and explains the ideas that underlie the conflict. What's at stake is nothing less than our understanding of space, time, matter and information!

Recorded: October 1, 2008
        Although this was taped some years ago, this was the most popular talk in the 24-year history of our series.  So we wanted to make it available as a podcast, so new audiences could also hear it.

A Non-technical Talk by Dr. Jessica Lu (University of California, Berkeley) on March 13, 2024

The population of black holes, objects left over from dead stars,  is almost entirely unexplored. Only about two dozen black holes are confidently known in our Galaxy. As a result, some of the most basic properties of black holes remain unknown, including the true number of black holes in the Galaxy, their masses and sizes, and how the black holes were formed.  Dr. Lu discusses how she and other astronomers are using "gravitational lensing" -- something predicted by Einstein’s work -- to open a new window onto black holes, and how the first free-floating black holes are now being discovered.  She explains, in everyday language, why astronomers expect that the number of known black holes will increase by a factor of 100 over the next decade.

Speaker: Dr. Brian Lantz (Stanford University)
Feb. 7, 2024
Measuring gravitational waves is a revolutionary new way to do astronomy.  They were predicted by Einstein, but it was not until 2015, that LIGO (the Laser Interferometer Gravitational-wave Observatory) first detected one of these waves. They were tiny ripples in space itself, generated by the collision of two black holes. Since then, LIGO and its international partners have measured nearly 100 signals. Dr. Lantz explains what we can learn from these bursts of energy and just how it is possible to measure a wave which stretches our detector 1000 times less than the diameter of a proton. And he discusses what's coming next in our search for these tell-tale ripples in space? 
Dr. Lantz is the scientific leader for the Advanced LIGO seismic isolation system,

Dr. Laura Schaefer (Stanford University):
Water is everywhere. Its atoms, hydrogen and oxygen, are the first and fifth most abundant elements in the universe. Water is found in abundance in many environments; it finds its way into planets of all shapes and sizes, where it modifies the properties of everything it touches. Water is crucial to life, both as a habitat and as a solvent. But it also has many other roles in the evolution of habitable and uninhabitable environments on a planetary scale. In this talk, Dr. Schaefer discusses the ways in which Earth acquired its water, how water modifies the evolution and habitability of the Earth, and how the habitability of rocky planets orbiting other stars may be different.  

Laura Schaefer is an Assistant Professor of Earth and Planetary Sciences at Stanford University. She is a planetary scientist who focuses on how gases and rocks react with each other to form the atmospheres of rocky planets, both inside and outside the Solar System.  

The talk was given November 15, 2023.

A Talk by Dr. Robert Jedicke (U of Hawaii)
Oct. 11, 2023

Near-Earth objects present both an existential threat to human civilization and an extraordinary opportunity to help our exploration and expansion across the solar system. Dr. Jedicke explains that the risk of a sudden, civilization-altering collision with an asteroid or comet has markedly diminished in recent decades -- due to diligent astronomical surveys -- but a significant level of danger persists. At the same time, remarkable strides have been made in advancing technologies that pave the way for a new vision of space exploration – one that involves missions and outposts within the inner solar system fueled by resources extracted from near-Earth asteroids. These objects contain exploitable extraterrestrial resources delivered free to the inner solar system, and they have been naturally preprocessed into objects the ideal size for industrial operations. 

Robert Jedicke obtained his Ph.D. in experimental particle physics from the University of Toronto and held post-doctoral positions at the Fermi National Accelerator Laboratory and at the University of Arizona’s Lunar & Planetary Laboratory. At the University of Hawai`i’s Institute for Astronomy for the last 20 years, he managed the development of the Moving Object Processing System for the Pan-STARRS telescope on Maui.

June 2012
Frank Drake (1930-2022) was known as the "father of SETI science" -- he was the scientist who conducted the first radio survey for signals from extraterrestrial civilizations, and came up with the formula for estimating the likelihood of such civilizations, now called the Drake Equation. 

In June 2012, the SETI Institute sponsored a three-day public event called SETICon. One highlight of the program was an interview with Drake (who served as the founding President of the Institute board. )  It was conducted by SETI Institute board member and veteran astronomy educator Andrew Fraknoi.  The discussion ranged widely over Dr. Drake's career and current thinking.  It included reminiscences of Project OZMA, that first experiment searching for signals from civilizations among the stars, and his current view of the Drake Equation.  He also reflects on a number of modern developments, including the discovery of numerous planets orbiting other stars and new ways of searching for extra-terrestrial civilizations.

During the Summer, when the Silicon Valley Astronomy Lectures take a vacation, we thought you might enjoy this special podcast for its historical value, now that Frank Drake has passed away.

with Dr. Eugene Chiang (University of California, Berkeley)
June 21, 2023
We now know that our solar system is but one of countless others. Where did all these planets come from? What are their fates, and ours? Dr. Chiang describes the life cycle of planets, how they are born and die, and how they are born again. The story combines the latest observations from a wide range of telescope with our evolving theoretical understanding of the role planets play in the development of the cosmos.

A Nontechnical talk by Dr. Steven Kahn (University of California, Berkeley)

Oct. 8, 2025

The amazing Vera Rubin Observatory is a unique astronomy facility just built in Chile, with the largest digital camera in the world, designed to provide a time-lapse “movie” of the entire sky from the Earth’s southern hemisphere.  Over its planned ten years of operation, the Rubin Observatory will obtain nearly 1,000 images of every part of that sky.  By comparing the various images, we will be able to detect everything that varies in brightness and everything that moves across the sky. By adding together all of the images, we will be able to catalog nearly 20 billion galaxies and a comparable number of stars.  After 20 years of development, this facility has just come on-line and will soon begin its nightly operations.  Prof. Kahn, who was Director of the Observatory during its construction phase, reviews the design, development, and construction of Rubin, and describes the exciting science that lies ahead.

North America will be treated to two eclipses of the Sun in the 2023-24 school year: an annular eclipse on Oct. 14, 2023 and a total eclipse on Apr. 8, 2024.  Some 500 million people will be in a position to see at least a partial eclipse on each date. Astronomer Andrew Fraknoi (Fromm Institute, University of San Francisco) discusses the cause of eclipses (and why Earth's eclipses are unique), the circumstances of each coming eclipse and where each will be visible, plus how to view eclipses safely.  He shows maps of the eclipse paths and provides URLs to where you can get free information materials to help you enjoy eclipses without hurting your eyes, wherever you are.   (For more about Andrew Fraknoi and his educational outreach work, see: http://fraknoi.com )

Dr. Alex Filippenko (University of California, Berkeley)
Mar. 8, 2023
We have a new supersensitive eye in the cosmic sky. Parked nearly one million miles from Earth, the James Webb Space Telescope (JWST) is 100 times more sensitive than the Hubble Space Telescope. JWST observes at the red to the mid-infrared parts of the spectrum, offering new insights into a vast array of objects and processes -- including solar system formation, star birth and death, galaxy evolution, and, perhaps, the origins of life. Dr. Filippenko is a member of several teams of astronomers who are and will be observing using JWST.  Showing some of the best new images, he gives us the inside scoop on what astronomers expect the telescope to do and what they have already learned from the first months of the telescope's operation.  

Dr. Filippenko was voted the University of California, Berkeley's "best professor" nine times! He has produced five astronomy video courses with The Great Courses, co-authored an award-winning astronomy textbook, and appeared in about 100 TV documentaries.

For centuries, humans have gazed at the night sky and wondered if any intelligent life forms like us might be out there.  In 2015, the Breakthrough Foundation gave a $100 million grant to the University of California at Berkeley to undertake the most comprehensive search for signals from an extra-terrestrial civilization. Dr. Steve Croft, of the University of California, Berkeley, SETI Center,  describes the project, introduces the many radio telescopes around the world it is using in the search, and explains how modern technology, including AI, is being used to  include more stars, more frequencies (channels) and more ways a signal might be sent.

Talk by Dr. Lynn Cominsky (Sonoma State University)
Gravitational waves are predicted by Einstein's General Theory of Relativity.  They travel at the speed of light, but are much harder to detect than light waves.  On September 14, 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) received the first direct gravitational wave signals.  The event that produced them was the merger of two distant and massive black holes that were in mutual orbit. Prof. Cominsky presents an introduction to LIGO, to gravitational waves and how they were detected, and to the kinds of black holes that "make waves" in the fabric of space and time.  Originally recorded on Nov. 2, 2016.

With Dr. Jeffrey Bennett (University of Colorado)

2015 marked the 100th anniversary of Einstein's completion of his General Theory of Relativity, the comprehensive theory of space, time, and gravity. In everyday language, Dr. Bennett explains the basic ideas of Einstein's work (both his special and general theories) and shows how Einstein's remarkable ideas are being confirmed today by a range of astronomical observations.  He concludes with four reasons why relativity should matter to everyone.  (Recorded in 2015)

Dr. Jeffrey Bennett is the lead author of one the most popular introductory astronomy textbooks, and has written a number of books for children as well as for teachers. He is considered one of the leading educators in the field of astronomy.

The Sun can unleash violent “space weather” -- storms that can radiate X-rays and even gamma rays into space, send giant clouds of magnetic plasma slamming into the Earth and other planets, and spray firehoses of charged particles throughout interplanetary space. On Earth, we are mostly protected from the Sun’s wrath by our magnetic field and atmosphere, but astronauts venturing to the Moon and Mars will be vulnerable to these potentially deadly solar storms. Dr. Tom Berger (University of Colorado) discusses our current understanding of the interplanetary space environment, describes some extreme space weather events in history, and examines how well we can currently predict space weather and its impacts.  Recorded Dec. 7, 2022.

Tom Berger is the Executive Director of the University of Colorado’s Space Weather Technology, Research, and Education Center, which combines traditional space physics research with technology and education to bridge the wide gap between research on the Sun and operational space weather forecasting. He was formerly the director of NOAA’s Space Weather Prediction Center, helped develop the world’s largest solar telescope on the island of Maui (the Daniel K. Inouye Solar Telescope), and has been a co-investigator on international missions to study changes in the Sun’s magnetic field.

with Dr. Dan Werthimer of the University of California, Berkeley

What is the possibility of other intelligent life in the universe and how might we detect signals from alien civilizations?  Dr. Werthimer describes current and future projects searching for such signals, including the new $100-million Breakthrough Prize Foundation "Listen" project  to "tune in" on messages that civilizations around other stars might be sending out.  He shows how new technologies are revolutionizing the search for extra-terrestrial intelligence (SETI).  
Dr. Werthimer was one of the founders of the SETI@home project, which analyzed data from the world's largest radio telescope using the desktop computers and cell phones of millions of volunteers.
Recorded on March 15, 2017

With Dr. Natalie Batalha (NASA, Kepler Mission Project Scientist)

NASA's Kepler Mission launched in 2009 with the objective of finding "Goldilocks planets" orbiting other stars like our Sun -- those that are not too hot, not too cold, but just right. The space telescope opened our eyes to the many terrestrial-sized planets that populate the galaxy (including several right in our neighborhood,) as well as to exotic worlds unlike anything that exists in the solar system.  Dr. Batalha gives an overview of the science legacy of the Kepler Mission and other key planet discoveries (including some results that were then only a few weeks old).  She also gives a preview of planet-finding missions to come.  

Recorded Nov. 8, 2017

In this episode, Dr. Victoria Kaspi (McGill University) introduces us to a brand-new mystery in the skies -- superfast bursts of radio waves whose source is still unknown.  These energetic bursts come from all over the sky (and all over the universe,) pack a huge amount of energy, and typically last a few thousandths of a second.  Like a detective in the middle of a case, Dr. Kaspi fills us in on the story of how new observations (especially with the CHIME telescope project which she heads) have been revealing tantalizing new aspects of these bursts, without yet giving us a solution to their ultimate cause.  She shares both the thrills and frustrations of a new phenomenon in science, still in the process of being explored.  Recorded on Oct. 19, 2022.

Victoria Kaspi is the inaugural director of the McGill Space Institute and holds the Lorne Trottier Chair in Astrophysics and Cosmology at McGill University.  She is the winner of the 2021 Shaw Prize in astronomy and the 2022 Albert Einstein World Award in Science.

with Prof. Eliot Quataert (University of California, Berkeley)

In the previous decade, one third of the world's astronomers became involved in a single project --  observing a distant and violent event,  when two "star corpses" called neutron stars collided and exploded.  This represented the first time in the history of astronomy that a cosmic event was observed with both gravity waves (first predicted by Einstein) and light.   We now call this event the birth of "multi-messenger astronomy."  Dr. Quataert gives a non-technical history of how we are now able to find gravity waves, what happens during such a merger, and why we now believe that much of the gold, platinum, uranium and other heavy elements in the universe is assembled in such "star corpse" mergers.  Recorded Jan. 24, 2018.

A Talk by Dr. Oliver White (SETI Institute)

May 28, 2025

Ten years ago, the New Horizons spacecraft flew by the Pluto system and revealed an unexpectedly diverse range of landscapes on that dwarf planet and its largest moon Charon -- implying much more complex geological histories for these distant worlds than anyone expected. Dr. White leads a vivid tour of their often bizarre terrains, some of which are still evolving, and explains what processes scientists think molded them into their present appearances. After a brief stop at Pluto's four small moons, Dr. White extends the tour 2 billion km farther out into space, to show us Arrokoth, the tiny "planetesimal" that New Horizons flew past three and a half years after visiting Pluto.  It is the most primitive object in the Solar System ever visited by a spacecraft.

Speaker: Dr. Ashwin Vasavada, of NASA’s Jet Propulsion Laboratory 

For five years, Curiosity explored Gale Crater, one of the most intriguing locations on Mars -- once the site of an ancient lake.  In this talk, the mission's Project Scientist discussed what the rover was capable of and the many things it discovered on and about  the red planet.  In particular, he fills us in on the evidence that ancient Mars, billions of years ago, was much more like the Earth -- with a thicker atmosphere and flowing water on its surface. (Recorded Feb. 28, 2018)

with Dr, Michael Busch (SETI Institute)
Near-Earth asteroids are a population of small bodies whose orbits around the Sun cross or come near our planet’s orbit.  They turn out to be unusual physical environments: essentially rubble piles. They represent a natural hazard we ignore at our peril, because some of these bodies have the potential to impact Earth.  Dr. Busch reviews the near-Earth asteroid population, programs to track and characterize such asteroids, and current efforts to address the danger of asteroid impacts.

In July 2015, the New Horizons spacecraft flew by Pluto, revealing its surface to our view for the first time. In this program, Drs. Alan Stern and David Grinspoon give us an insider's view of how this complex mission came to be and what it discovered at the edge of our solar system.  Their recent book  (with the same title) tells the full story of the mission, its ground-breaking discoveries at Pluto, and where it's going next.  Here is the story of path-breaking exploration and new science, straight from the source, with insight into what it's like to be part of a  planetary mission that goes to a destination never before visited.  (Recorded May 15, 2018)

Dr. Sandra Faber (University of California, Santa Cruz)
Do Humans Have What it Takes to Thrive in this Universe?

In this thought-provoking talk, cosmologist (and National Medal of Science winner) Dr. Sandra Faber takes a look at our cosmic origins, the future of the Earth as a habitable planet, and what humans need to do to thrive in the long-term future.  She draws some sobering conclusions from the laws of physics and the sustainability of our present-day use of energy and resources.  And she provides some clear guidelines on what we will need to do, as a species, to continue living on Earth for as long as our durable planet can provide an inviting home for us.  (Recorded May 25, 2022)

When light from space enters Earth’s atmosphere, it is distorted and displaced, something our eyes perceive as “twinkling.”  Adaptive optics can remove a great deal of this distortion, essentially restoring much of the detail we’ve been robbed off in our view of the stars and galaxies.  Dr. Max, a world-renowned pioneer in this technique, shows us how modern lasers allow her to do this very precisely.  And she discusses how this technique is giving us sharper views of such cosmic events as the collision of nearby galaxies.

Speaker: Dr. Claire Max (University of California Observatories)
Oct. 3, 2018

In this talk, astrobiologist Charles Lineweaver discusses the history of life on Earth and what we can deduce from our understanding of the universe about the existence and history of life elsewhere.  He recounts the ongoing discovery of large numbers of exoplanets -- planets orbiting other stars -- and what we can learn from the varieties of planets that are being found.  He challenges us to think about what parts in the development of intelligent life on Earth would necessarily happen elsewhere and what parts might be unique to our planet. 

Charles Lineweaver is an honorary associate professor at the Australian National University’s Research School of Astronomy and Astrophysics and Research School of Earth Science. His research areas include exoplanetology (the statistical analysis of exoplanets and their habitability), cosmobiology (using our new knowledge of cosmology to constrain life in the Universe) and the study of cancer. He recently completed an online video course at: arewealone.us. Dr. Lineweaver earned a BA in history from the State University of New York at Binghamton, an MA in English from Brown University, a BS is physics from Ludwig Maximillian's University in Munich, and a PhD in physics at the University of California, Berkeley in 1994. 

What would it have been like to be an eyewitness to the Big Bang? In 2014, astronomers using the powerful BICEP2 telescope at the South Pole thought they’d glimpsed evidence of the period of cosmic inflation at the beginning of time. Millions around the world tuned in to the announcement, and Nobel whispers spread like wildfire. But had these scientists been deceived by a galactic mirage? In this popular-level talk, cosmologist Brian Keating tells the inside story of BICEP2’s detection and the ensuing scientific drama. He provocatively argues that the Nobel Prize actually hampers scientific progress by encouraging speed and competition while punishing inclusivity, collaboration, and bold innovation.   

 Dr. Keating is s a cosmologist at the University of California San Diego and Principal Investigator of the Simons Observatory collaboration in Chile.  He is the author of a popular book, Losing the Nobel Prize: A Story of Cosmology, Ambition, and the Perils of Science’s Highest Honor.

This talk was recorded on Nov. 14, 2018.

New exploration indicates that caves may be more common on rocky and icy worlds in our Solar System than we have thought in the past. Caves below the Earth show us a very different planet than the familiar one we experience on the surface.  Each dark cave system has its own micro-organisms and distinctive mineral and chemical properties.  Dr. Penelope Boston, NASA Ames Research Center, takes us on a tour of the some of the most spectacular caves under the Earth and the unusual life-forms they harbor, and considers how the lessons they teach us can be applied to the exploration of the Solar System, especially the icy moons of the giant planets.
(Recorded Feb. 27, 2019)

In this illustrated talk, Dr. Burgasser explains what happens when a newly forming star doesn't have "what it takes" to produce energy in its core in an ongoing way.  This results in "failed stars" or brown dwarfs -- objects that were predicted in theory, but only discovered in the 1990's.   Today, many thousands of these brown dwarfs are known, spanning a wide range of temperatures and masses, and occupying a unique niche at the intersection of stars and planets. Dr. Burgasser discusses how such faint objects are discovered, highlights their exceptional properties, and describes what this (mostly) invisible population can tell us about the formation and history of our Milky Way Galaxy.   Recorded March 9, 2022.

Adam Burgasser is a professor of Physics at the University of California,  San Diego, and an astrophysicist who studies the coldest stars, brown dwarfs, and extrasolar planets. Prof. Burgasser defined the “T spectral class” of brown dwarfs as a graduate student; and is one of the co-discoverers of the TRAPPIST-1 exoplanetary system, a system of seven Earth-sized planets orbiting an object at boundary of the star/brown dwarf divide. 

Pluto’s large moon Charon turned out to be far more interesting than astronomers expected.  Pluto was the star when the New Horizons probe flew by, but the features on Charon’s surface tell a fascinating tale of how icy worlds could form far from the gravitational influences of the giant planets.  There is evidence of a world-wide sub-surface ocean early on, and of global expansion as that ocean froze solid.  Charon’s surface also has a region of plains where icy materials may once have flowed and smoothed over the fractures present elsewhere on its surface.  Dr. Beyer is your expert guide through this story of formation and change in the frozen reaches of the outer Solar System.

Dr. Ross Beyer is a Planetary Scientist with the Carl Sagan Center at the SETI Institute and at NASA's  Ames Research Center. 

This talk was given May 15, 2019

Non-technical Talk by Prof. Jonathan Fortney (U. of California, Santa Cruz) 
Apr. 9, 2025

Over 6000 planets have now been found around other stars, but we only have information about what their atmospheres are like for a few dozen.  NASA's powerful James Webb Space Telescope (JWST), which features a 20-foot mirror in space, is currently being used to understand planetary atmospheres.  Prof. Fortney explains how we can look for atmospheres around rocky planets the size of the Earth, and how his group and others are already measuring the abundances of molecules like water, methane, ammonia, and carbon dioxide in the atmospheres of larger planets, of sizes similar to Neptune and Jupiter.  And he tells us what astronomers are looking forward to in the next year or two with JWST.

In this nontechnical talk, illustrated with the latest images and video, Dr. Thaller asks what makes a world habitable?  What creates and sustains an environment friendly to life?  She then discusses the history of life on Earth and what we are learning about our planet, and our neighbors Mars and Venus from such missions as the Parker Solar Probe, the laboratories aboard our Mars rovers, and the probes that have explored asteroids and comets, including one that is bringing samples back to Earth as we speak. Finally, she touches on the way new instruments, like the James Webb Space Telescope, will help us learn if there are habitable worlds around other stars.

Dr. Michelle Thaller is the liaison between the Office of Communication and the Science Directorate at NASA Goddard. Outside her work at NASA, she has appeared in many television science programs, including How the Universe Works and Space’s Deepest Secrets.

Decades after we last set foot on the Moon, and several years after the Space Shuttle was retired, space activity is finally leaving the doldrums.  Permanent bases on the Moon and Mars are now within reach, and a new Space Race is brewing, with Asian countries ascendant. Dr. Impey (University of Arizona) reviews the history and landmarks of the international space program, gives a snapshot of the current situation, and plots the trajectory of the future of space travel.  Recorded on Feb. 15, 2017.  (Dr. Impey has written a book with the same title as this talk.)

 Where is the best place to find living life beyond Earth? It may be that the small, ice-covered moons of Jupiter and Saturn harbor some of the most habitable real estate in our Solar System. Life loves liquid water and these moons have lots of it!  Such oceans worlds have likely persisted for much of the history of the solar system, and as a result they are compelling targets for our exploration. Dr. Kevin Hand (of the Jet Propulsion Lab) explains the science behind our understanding of these worlds, with a special focus on Jupiter’s intriguing moon Europa, which is a top priority for future NASA missions.   Dr. Hand is also the author of a popular-level book "Alien Oceans: The Search for Life in the Depths of Space."  (Recorded Apr. 10, 2019.)

Dr. Hand is a planetary scientist at JPL in Pasadena, California and the Director of its Ocean Worlds Lab. His research focuses on the origin, evolution, and distribution of life in the solar system with an emphasis on Europa.  From 2011 to 2016, Hand served as Deputy Chief Scientist for Solar System Exploration at JPL. His work has brought him to the Dry Valleys of Antarctica, the sea ice near the North Pole, the depths of the Earth’s oceans, and to the glaciers of Kilimanjaro. Dr. Hand was a scientist onboard James Cameron’s 2012 dive to the bottom of the Mariana Trench, and he was part of a 2003 IMAX expedition to hydrothermal vents in the Atlantic and Pacific oceans. 

The NASA Kepler mission revealed that our Galaxy is teeming with planetary systems and that Earth-sized planets are common.  However, most of the planets detected by Kepler orbit stars too faint to permit detailed study. The NASA Transiting Exoplanet Survey Satellite (TESS,) launched in 2018, is finding hundreds of small planets orbiting stars that are much closer and brighter.  Dr. Dressing (Assistant Professor of Astronomy at the University of California, Berkeley) describes the TESS mission and explain how analyses of the TESS planets allows us to probe the composition of small planets, investigate the formation of planetary systems, and set the stage for the next phase of exoplanet exploration: the quest for the signatures of life in the atmospheres of strange new worlds.

The Vera Rubin Observatory will house a survey telescope that will image the night sky faster and deeper than ever before. Its camera, at 3.6 Gigapixels, will be the biggest digital camera ever built. The Rubin Observatory will be able to image the entire visible sky every few nights, and build up, over 10 years, a 900-frame full color movie of the deep night sky. This will enable a wide variety of scientific explorations, from the outer reaches of our Solar System, through our Milky Way Galaxy and its dark matter halo, and out into the extra-galactic universe, where we hope to see new types of cosmic explosions and the weird effects of the mysterious Dark Energy.  Dr. Phil Marshall (of Stanford University) gives a guided tour of the  Observatory, describes the planned sky survey, discusess the challenges of doing astronomy at petabyte scale, and shows how we can all take part in Rubin's voyage of discovery.
 
 

Prof. Jim Bell (of Arizona State University), who is a key leader in projects to take images with NASA's rovers on Mars, discusses the history and current state of our exploration of the red planet.  He summarizes the scientific findings from the Spirit, Opportunity, Curiosity, and Perseverance missions. He puts each mission into the larger context of the questions we are asking -- both about Mars today and about ancient Mars, which could have been far more hospitable for life.

A bird that mimicked a black hole. The astronomer that discovered microwave ovens. A telescope that got shot. The science of astronomy is filled with true stories (and tall tales) of the adventures and misadventures that accompany our exploration of the universe. Dr. Levesque, who interviewed over 100 astronomers for her well-reviewed popular book, The Last Stargazers,  takes us on a behind-the-scenes tour of life as a professional astronomer. We learn about some of the most powerful telescopes in the world and their cutting-edge discoveries, meet the people behind the science, and explore the crucial role of human curiosity and innovation in the past, present, and future of scientific discovery.  (Recorded on Oct. 20, 2021)

Emily Levesque is an astronomy professor at the University of Washington.  She has observed for upwards of fifty nights on many of the planet’s largest telescopes and flown over the Antarctic stratosphere in an experimental aircraft for her research. 

Craig Venter & Daniel Cohen suggested that if the 20th century was the century of physics, the 21st century will be the century of biology on our planet.  Jill Tarter believes that their idea will be extended beyond the surface of our world, and that we may soon have the first opportunity to study biology that developed on other worlds.  In this lecture, recorded in 2017, she talks about her vision of the future of understanding life on Earth and beyond our planet.  And she discusses projects that are underway and are planned to learn more about the possibility of intelligent life among the stars.  The talk also celebrated the publication of the book "Making Contact" (by Sarah Scoles) about Jill Tarter's life and work.

By measuring the rapid orbits of the stars near the center of our galaxy, Dr. Andrea Ghez of UCLA and her colleagues have moved the case for a supermassive black hole at the heart of our Milky Way Galaxy from a possibility to a certainty.  She reports on her pioneering observations of stars near our galaxy's center (that orbit the monster black hole) and discusses some of the surprising results this work has led to.  The talk was recorded in January 2017; in 2020, Dr. Ghez won the Nobel Prize in physics for this work.

After encountering Pluto, the New Horizons spacecraft, for the first time flew by a member of the Kuiper Belt of icy objects beyond Neptune.  This particular object, informally named “Ultimate Thule” (meaning the farthest place beyond the known world,) turned out to be a “contact binary” – two smaller icy worlds stuck together. Dr. Jeff Moore, a planetary scientist at NASA Ames Research Center,  shares an insider’s view (with great images) of how the mission got there and what we learned at Ultima Thule.  This talk was recorded Oc.t 19, 2019.  Since then this object has been given the official name Arrokoth.

 Mar. 5, 2025

 Dr. Simon Steel (SETI Institute)

Dr. Steel discusses the Copernican revolution and how it changed humanity's view of its place in the universe. He then talked about other "Copernican" discoveries that displaced us from a central perch, including the revision of our place in the Galaxy, the discovery of other galaxies, and now our finding a remarkable number of planets (including Earth-like planets) orbiting other stars.  He explains how such discoveries give context for, and have prepared us for, the next potential Copernican revolution, the discover of intelligent life elsewhere in the cosmos. He concludes by describing some of the most exciting experiments now underway to find evidence of such life among the nearest stars and busiest galaxies.  Dr. Steel is  Deputy Director of the Carl Sagan Center for Research at the SETI Institute.

Black holes are one of the most remarkable predictions of Einstein's theory of gravity: so much material is compressed into such a small volume that nothing, not even light, can escape.  In Spring 2019, the world-wide Event Horizon Telescope released the first real picture of gas around a massive black hole and the “shadow” it makes as the gas swirls into the black hole.  Dr. Quataert (University of California, Berkeley) describes how these pioneering observations were made and what they have taught us about black holes.

Recorded on Jan. 22, 2020

Dr. Adam Frank (U of Rochester) first discusses the history of our search for extra-terrestrial intelligence (SETI), including the Drake Equation, the Fermi Paradox, and the searches for radio messages from other civilizations that have taken place since 1960.  He then explains how new research and funding is expanding our thinking about the ways we might find evidence of intelligent life among the stars.  He focuses on "techno-signatures" -- ways in which we might identify signs of alien technology.  Dr. Frank summarizes the work in papers he has published and the research and ideas of scientists around the world.  (Recorded May 26, 2021.)

Dr. Brown (whose discovery of dwarf planet Eris led to the reclassification of Pluto) discusses the history of planetary discovery (and demotion), why we think a new, larger Planet 9 is on the verge of being found, and the techniques that we are using to try to find this very faint body lurking in the far reaches of our planetary system.  This was recorded Nov. 11, 2020. 

May 22, 2021,  Dr. Janna Levin (Columbia University's Barnard College)
Dr. Levin helps us to understand, and to find delight in, black holes – perhaps the most opaque theoretical construct ever imagined by physicists. She takes us on an exploratory tour of the neighborhood of a black hole, and help us feel the visceral experience of encountering black holes of different masses.  The title of the talk is also the title of her recently published popular-level book.  (Originally scheduled for April, this talk had technical problems, and was re-recorded successfully in May.)