Silicon Valley Astronomy Lectures
Taking a Hit: Asteroid Impacts and Evolution
Dr. David Morrison (NASA Ames Research Center)
Listen (mp3 file, 18.9 MB)
Asteroids have hit the Earth many time in the past, and they will continue to hit in the future, whether we are prepared or not. Collisions with our planet over 4.5 billion years have profoundly influenced the evolution of life. (In fact, were it not for the impact of a 15-km wide asteroid 65 million years ago, it is likely humanity would not be here.) Dr. Morrison, one of the world’s experts on the study of asteroid impacts, discusses the past and the future of these catastrophic hits, and explains how, in the last two decades, we have learned (in principle) how to defend ourselves. Unlike other natural hazards, we now have the capability of removing most of the impact risk within the next generation. However, the government still does not have a plan of action for when an asteroid is discovered heading our way or when an impact happens without any warning. (We recommend you listen to this podcast holding hands with someone you love.)
A Ringside Seat to the Formation of Planets
Dr. Dana Backman (SETI Institute and Astronomical Society of the Pacific)
Listen (mp3 file, 19.8 MB)
Astronomers have discovered dusty “doughnuts” of cosmic raw material around many younger stars. In some cases, astronomers can see tantalizing hints in the rings that planets may be forming or may already have formed from this material. Dr. Backman explains how new kinds of telescopes and observations are making it possible for us to detect the birth process of planets around nearby stars. He concludes by previewing future observations of these intriguing dusty rings with upcoming telescopes, particularly the SOFIA (Stratospheric Observatory for Infrared Astronomy) Project in which NASA has outfitted a 747 plane with a telescope that can observe heat-rays from distant objects.
Comparing Worlds: Climate Catastrophes in the Solar System
Dr. David Grinspoon (Denver Museum of Nature and Science)
Listen (mp3 file, 22.3 MB)
Take an entertaining and enlightening journey with an astronomer and popular author through the history of our solar system, discovering runaway greenhouses and snowball planets. Compare the evolution of Venus, Earth, and Mars over the years. And learn how studying the evolution of other planets can help us understand and predict climate change on Earth.
A Scientist in Space and Searching for Earth-like Planets: NASA’s Kepler Mission
Dr. Janice Voss (NASA Ames Research Center)
Listen (mp3 file, 17.5 MB)
Dr. Voss, who has logged 49 days in space (traveling almost 19 million miles in 779 Earth orbits) discusses her work in space and what it’s like flying on the Shuttle as a scientist. She then talks about NASA’s upcoming Kepler mission, which will use a telescope in space to search for “transits” — when a planet orbiting another star moves in front of its star and blocks its light. Although a planet might only block a tiny fraction of the light from a star, that decrease in brightness is enough to give a clear signal that the planet is there. With this mission, scientists hope to be able to find not only Jupiter and Saturn-sized planets, but also those as small as Earth. At the end, Dr. Voss answers a number of audience questions about both aspects of her work.
Glimpsing the Edge of the Universe: Results from the Hubble Space Telescope
Dr. Bruce Margon (University of California, Santa Cruz)
Listen (mp3 file, 24 MB)
The Hubble Space Telescope has circled the Earth 15 times every day for more than 16 years. Dr. Margon, who was until recently the Associate Director for Science for the Hubble, describes the most important discoveries made with the telescope and how it can show us new details of the universe from the solar system to the most distant reaches of space. In addition, he briefly discusses the future of the Hubble and some interesting public reactions to it.
The Planet Pluto: Maligned but Not Forgotten
Dr. Dale Cruikshank (NASA Ames)
Listen (mp3 file, 20.3 MB)
Dr. Cruikshank reviews what we knew about Pluto (including its atmosphere, of which he was the co-discoverer), why Pluto was re-classified as a dwarf planet in the fall of 2006, and what the New Horizons spacecraft may reveal about this distant world in the next decade.
Dark Energy and the Runaway Universe
Dr. Alex Filippenko (University of California, Berkeley)
Listen (mp3 file, 24.7 MB)
In 1998, observations of very distant exploding stars provided intriguing evidence that the expansion of the Universe is speeding up with time, rather than slowing down due to gravity as expected. Today, new and completely independent observations strongly support this amazing conclusion. Over the largest scales of space, our Universe seems to be dominated by a repulsive “dark energy,” stretching the very fabric of space itself. Dr. Filippenko, who is a leader in the group that has made some of these remarkable observations, gives us a progress report on our “runaway universe” and then answers a host of audience questions about the overall behavior of the universe.
The Mars Exploration Rover Mission: A Year of Exploration and Discovery
Dr. Nathalie Cabrol (SETI Institute)
Listen (mp3 file, 18.3 MB)
Dr. Nathalie Cabrol is a planetary geologist who is a member of the Science Team for the Mars Exploration Rover mission. She specializes in exploring regions of Earth that resemble Mars (including Licancabur, the highest lake on our planet). She was instrumental in the selection of one of the landing sites for the Mars rovers and is busily analyzing images and data from the mission. In this 2005 lecture, she gave an early progress report on the work of the Spirit and Opportunity rovers, and some of their discoveries about the red planet.
Estimating the Chances of Life Out There
Dr. Frank Drake (SETI Institute, University of California, Santa Cruz)
Listen (mp3 file, 16.9 MB)
In 1961, Dr. Drake proposed an intriguing method of estimating the number of intelligent life-forms out there that we might communicate with, now called the Drake Equation. In this talk, Dr. Drake provides a modern update on estimates for the existence of “E.T.” He draws on new ideas and new observations (including the discovery of surprising planets around other stars), which have helped astronomers refine both the targets where they search for life and the methods they use.