The Search for Earth 2.0

Oct. 7, 2026Jessie Christiansen (CalTech) "The Search for Earth 2.0: Why We Think It Exists, & How We’re Going to Find it " For thousands of years, we’ve wondered if the Earth is unique, or if there are other Earths out there. In just the last 30 years, we’ve progressed from merely wondering if planets exist around other stars to knowing that almost every star we see has planets. However, we have yet to discover another planet that might be like Earth – a rocky planet orbiting just the right distance from a Sun-like star to have liquid water on its surface. NASA has an audacious new plan for a next-generation flagship telescope that will directly image Earth-like planets around nearby stars, but it will take all of our ingenuity and technical prowess to achieve this feat. Dr Christiansen (the Chief Scientist of the NASA Exoplanet Science Institute) walks us through the past, present, and future of our hunt for Earth 2.0.

May 20, 2026Dr, Hakeem Oluseyi (CEO, Astronomical Society of the Pacific)n his new book, Why Do We Exist, Dr. Oluseyi suggests that the story of our existence can be told as a passage through nine interwoven realms—each revealing a new layer of cosmic information. In this public talk, he introduces each of the realms, but then focuses on cosmic connections to the Middle Realm, where we humans live, and to the Realm of Life, where organisms flourish across the vastness of space. He explores these realms with humor and honesty, weaving in stories from his early life in Mississippi and his career in science.

Dr. Lindy Elkins-Tanton, Space Sciences Laboratory at the University of California, Berkeley,Apr. 8, 2026.The NASA Psyche mission is on its way to orbit a small but immensely ancient world in our asteroid belt: A metallic object, the first humans will ever have visited. When our solar system was in its infancy, thousands of planetesimals (tiny planet-like objects) formed in less than a million years. Many planetesimals later melted, allowing metal cores to form inside rocky mantles. One of these metal cores may be revealed in the asteroid (16) Psyche. Dr. Elkins-Tanton, the Mission Lead, takes us behind the scenes in planning and carrying out this remarkable mission of exploration, which launched in 2023, and updates us of where we are over two years post-launch.

A nontechnical talk by Dr. Bruce Macintosh (University of California Observatories)Mar. 11, 2026In the past three decades, more than 6000 planets have been discovered orbiting other stars.  Advances in technology have allowed a handful of giant planets around other stars to be imaged directly. Dr. Macintosh tells us about the first-ever images of other solar systems — and the technology that has allowed us to discover them, such as the Gemini Planet Imager — as well as the future planet-hunting space telescopes. The ultimate goal is detection of a second ‘pale blue dot’ — an Earth twin where we could even see the biosignatures of extrasolar life.  (He also talks a bit about the wind damage to the Lick Observatory and what is being done to repair the historic dome.)Bruce Macintosh is the Director of the University of California Observatories in California and Hawaii. He co-led the team that imaged the first extrasolar planets, and was the Principal Investigator of the Gemini Planet Imager, an advanced planet-finder for the Gemini South telescope.

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, 2025In 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.

A Nontechnical talk by Dr. Steven Kahn (University of California, Berkeley)Oct. 8, 2025The 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.

A Talk by Dr. Oliver White (SETI Institute)May 28, 2025Ten 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.

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

 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.