Silicon Valley Astronomy Lectures
Black Widow Pulsars: The Vengeful Corpses of Stars
Dr. Roger Romani (Stanford University)
Listen (mp3 file, 22.2 MB)
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.
The Chelyabinsk Meteor: Can We Survive a Bigger Impact?
Dr. David Morrison (SETI Institute and NASA Ames Research Center)
Listen (mp3 file, 26.4 MB)
In February 2013, a rocky projectile entered the Earth’s atmosphere and its explosion, at an altitude of 14 mi, released energy equivalent to a couple dozen Hiroshima-sized atom bombs. About two minutes later, the shock wave reached the ground in Chelyabinsk, Russia, breaking windows and injuring about 1500 people from flying glass. Has this event served as a kind of cosmic wake-up call for planetary defense? NASA recently announced a “grand challenge” to find all asteroids that could threaten human populations, and to figure out how to deal with them. David Morrison, a nationally-recognized expert about asteroids, discusses the Russian impact and evaluates ways we might meet the grand challenge to protect our population from space debris.
How the Universe Went from Smooth to Lumpy: The Modern Origins Story
Dr. Eliot Quataert (University of California, Berkeley)
Listen (mp3 file, 33.9 MB)
Dr. Eliot Quataert provides an overview of the modern understanding of our origins in astrophysics. The story begins in the infant universe, which we now know was remarkably smooth compared to what we see around us today, with only tiny differences in its properties from one part to another. By contrast, in the present universe there are enormous differences in the properties of matter in different locations. Dr. Quataert describes how the universe has evolved to its current state, emphasizing how gravity reigns supreme and builds up the planets, stars, and galaxies required for biological evolution to proceed.
Being a Mars Rover: What It’s Like on the Surface of Mars
Dr. Lori Fenton (SETI Institute)
Listen (mp3 file, 25.1 MB)
The complex, yet flawless landing of the rover Curiosity on Mars in August 2012 led to worldwide acclaim. What has NASA’s youngest robot been up to since then, and what has it discovered? Where on Mars did it land and why was that site chosen above all others? Dr. Fenton gives an overview of the rover’s capabilities, accomplishments, and plans on Mars, and describes what it’s really like on the surface of the red planet.
Free-floating Planets: When You’re Just Too Small to be a Star
Dr. Gibor Basri (University of California, Berkeley)
Listen (mp3 file, 34.4 MB)
The least massive star is six times heavier than the most massive known planet. In between is the realm of the mysterious “brown dwarfs.” The first of these was discovered only in 1995, the same year astronomers found the first planet beyond our solar system. Since then we have found hundreds of each, and new techniques are giving us even more power to probe the properties of these enigmatic bodies. Dr. Basri, one of the discoverers of brown dwarfs, summarizes the progress we have made in understanding the domain of cosmic objects that don’t qualify as stars.
Astronomy from the Stratosphere: NASA’s SOFIA Mission
Dr. Dana Backman (Director of Education & Public Outreach, SOFIA Project, NASA Ames Research Center)
Listen (mp3 file, 28.1 MB)
Why did NASA buy a used passenger airliner, cut a 10′ x 10′ hole in the fuselage, add a roll-back door, and install a 17-ton telescope inside? Dr. Backman introduces us to the engineering marvel called SOFIA — the Stratospheric Observatory for Infrared Astronomy. This remarkable airborne telescope began scientific research flights in 2010 and is already returning exciting discoveries about the birth of stars, interstellar chemistry, the atmospheres of giant planets, the environment around supermassive black holes, and other branches of astronomy.
How Galaxies were Cooked from the Primordial Soup
Dr. Sandra Faber (University of California, Santa Cruz and University of California Observatories)
Listen (mp3 file, 29.5 MB)
The lumpiness of today’s universe of galaxies is a fundamental characteristic that took billions of years to grow. Dr. Faber reviews the prevailing “Cold Dark Matter” theory for galaxy formation (which she helped create) and compares its predictions to present-day observations. It’s a remarkable saga involving invisible dark energy and matter, the properties of the Universe an instant after it was born, and the creation of structure from quantum fluctuations. (Just a few days before giving this talk, Dr. Faber received the 2013 National Medal of Science from President Obama, and she shares an anecdote from that ceremony.)
Black Holes: The End of Time or a New Beginning?
Dr. Roger Blandford (Kavli Institute, Stanford University)
Listen (mp3 file, 32.9 MB)
While black holes are popularly associated with death and doom, astrophysicists increasingly see them as creators, not destroyers — playing a major role in the formation and evolution of galaxies, stars, and planets. Dr. Blandford (whose research interests include black holes, galaxies, and cosmology) summarizes why scientists now think that black holes of various sizes actually do exist, describes some of their strange properties, and explains their “environmental impact” on the universe at large.
Finding the Next Earth: The Latest Results from Kepler
Dr. Natalie Batalha (NASA Ames Res. Ctr.)
Listen (mp3 file, 32.9 MB)
Dr. Batalha (Mission Scientist for the Kepler Mission searching for exoplanets) describes the techniques used by the Kepler team to identify planets orbiting other stars and updates us on the remarkable progress they are making in the search for Earth-sized worlds. She discusses the planets already found and shares what we know so far about the thousands of candidate planets that are in the Kepler data.
Multiple Universes and Cosmic Inflation: The Quest to Understand Our Universe (and Find Others)
Dr. Anthony Aguirre (University of California at Santa Cruz)
Listen (mp3 file, 24 MB)
Our improving understanding of the cosmos points to an early epoch during which the universe expanded at a stupendous rate to create the vast amount of space we can observe. Cosmologist are now coming to believe that this “cosmic inflation” may do much more: in many versions, inflation goes on forever, generating not just our observable universe but also infinitely many such regions with similar or different properties, together forming a staggeringly complex and vast “multiverse”. Dr. Aguirre traces the genesis of this idea, explores some of its implications, and discusses how scientists are seeking ways to test this idea.