A half-century ago, astronomers began trying to "eavesdrop" for radio messages from nearby star systems. However, today, SETI researchers continue to point their telescopes at individual stars, on the assumption that technically advanced societies will inhabit a watery world like our own. Dr. Seth Shostak of the SETI Institute describes these searches, but then discusses some novel ideas for how we might pursue the hunt for "cosmic company" and why it's possible that we might find evidence of sophisticated intelligence out there within only a few decades. Seth Shostak is Senior Astronomer at the SETI Institute, in Mountain View, California and hosts the syndicated radio show called "Are We Alone?" Recorded January 20, 2010.

Astrobiologist Dr. Lynn Rothschild of the NASA Ames Research Center has gone from the Bolivian Andes to the Rift Valley of Kenya searching for the hardiest of organisms in the most extreme environments for life. By getting to know life forms on Earth that can occupy the most hostile niches, we can begin to understand the survival requirements for life in general. She describes her quest for "life at the edge" and how such discoveries will shape our search for life in the Solar System and beyond. Recorded November 11, 2009.

Paul Kalas was the leader of the team who managed the long-sought feat of actually taking a photograph of a planet orbiting another star. Before this, all the planets outside our solar system were found by indirect means. He describes how they achieved the breakthrough, using the Hubble Space Telescope, and discusses the wide range of planets out there that astronomers are discovering. Recorded October 7, 2009.

In the last decade or so, astronomers have been forced to accept two mysterious observations. About a quarter of the universe is made of "dark matter," which attracts things with its gravity, but is otherwise invisible. And roughly two-thirds of the universe is composed of "dark energy," which causes space itself to expand at an ever-increasing rate. That means only a small fraction of the universe is made of ordinary matter -- the stuff we understand! In this non-technical presentation, Dr. Patricia Burchat of Stanford University explores the evidence for the dark side of the cosmos, and the experiments that are being developed to investigate it further. Recorded May 20, 2009.

Scientists searching for life elsewhere have to worry about avoiding harmful cross contamination during the exploration of planets and their moons. We don't want to take Earth microbes to Mars or bring back alien microbes to Earth. In this timely talk, Dr. Margaret Race of the SETI Institute gives a behind-the-scenes view of "environmental management" planning for solar system missions, and explains the role of the Outer Space Treaty and other related national and international policies in planning our hunt for life-forms out there. Recorded April 22, 2009.

All the great islands of stars got their start in the first billion years after the beginning of time, the Big Bang. Every deep picture of the sky reveals thousands of these galaxies, each made up of billions of stars like the Sun. Modern instruments like the Hubble Space Telescope have made it possible to look back to a time when the universe looked very different that it does today. Dr. Stephen Beckwith of the University of California discusses some of the deepest images of the universe ever taken and shares recent discoveries about the early days of the cosmos. Recorded March 4, 2009.

In 2009, NASA will purposely crash two spacecraft into one of the Moon's polar regions. The impacts should raise huge plumes of material, visible even to smaller telescopes on Earth. Dr. Anthony Colaprete (NASA Ames Research Center), the Principal Investigator for this intriguing mission, fills us in on why scientists believe there is water in deep craters at the Moon's poles and how the LCROSS mission plans to look for it in the plumes. Recorded January 21, 2009.

NASA's Cassini spacecraft has entered its fifth year exploring the planet Saturn, its rings, and its moons. Dr. Mark Showalter (SETI Institute), a key member of the Cassini science team, shares some of the marvelous results from Saturn and recent discoveries from the mission. His special focus is Saturn's complex and beautiful ring system (which shows a variety of surprising phenomena, including "jets", "propellers", "wisps", "spokes", and "braids") and the remarkable interactions between Saturn's rings and moons. Recorded November 12, 2008.

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 Leonard Susskind of Stanford University and a Dutch colleague have 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.

Dr. Jill Tarter of the SETI Institute is the leader of the main project looking for radio signals from alien civilizations (she was also the model for the character Jodie Foster played in the movie "Contact.") She updates us on the latest tools and plans in this quest, as digital technologies make possible huge improvements in our search systems. The Allen Telescope Array, being constructed in Northern California, will be the most powerful tool for finding SETI signals ever built. It is an innovative radio telescope assembled from a large number of small dishes, using consumer off-the-shelf technologies whenever possible to minimize costs. In the next decade, this new instrument will enable exploration that is 1000 to 10,000 times more sensitive than in the previous decades. This may just be enough! Recorded April 23, 2008.