SETI Institute Weekly Colloquium
At the Microsoft Campus in Mountain view
1065 La Avenida St, Mountain View CA
FREE and open to the public. Tuesdays, noon to 1pm
Although our planet is approximately 4.5 billion years old (Ga), Earth’s fossil record extends only to 3.5 Ga, the chemofossil record arguably to 3.8 Ga, and the rock record to 4.0 Ga. However, detrital zircons from Jack Hills, Western Australia range in age up to nearly 4.4 Ga. From a population of over 10,000 zircons from this locality, we identified one 4.10 Ga zircon that contains primary graphite inclusions in a crack-free region, and report carbon isotopic measurements on the graphite. Evidence for carbon cycling or biologic activity can be derived from carbon isotopic studies, since a high ratio of 12C/13C is characteristic of biogenic carbon. The 12C-rich isotopic signature of these graphite inclusions is consistent with a biogenic origin and may be evidence that a terrestrial biosphere had emerged by 4.1 Ga, or ~300 million years earlier than has been previously proposed.
Dr. Andrew Siemion, Director of the Berkeley SETI Research Center (BSRC) at the University of California, Berkeley, will present an overview of the Breakthrough Listen Initiative, 100-million-dollar, 10-year search for extraterrestrial intelligence. Dr. Siemion will also discuss other SETI efforts ongoing at the BSRC, including the successful citizen science project SETI@Home, as well as a concerted effort to undertake panchromatic observations of the mysterious Kepler star KIC 8462852.
(2) using the fission fragments of related nuclear fission reactions for ion-propulsion that produces rockets two to three orders of magnitude faster than achievable with chemical rockets, making possible, perhaps, a first generation of starships.
The outer reaches of our Solar System are home to hundreds of thousands of small icy worlds. Their present orbits are a sculpted signature of the early migrations of the giant planets, particularly Neptune. Yet the faintness and highly eccentric orbits of most of these worlds mean only a tiny fraction of them have yet been discovered. With the Outer Solar System Origins Survey on CFHT, we are discovering up to five hundred new outer Solar System objects, with exquisitely well-determined orbital parameters. Our complementary Large Program on Gemini North is observing the brightest of our discoveries in the optical and infrared with unprecedented precision, providing information on the ices, silicates and organic compounds on the surfaces of these small worlds. This colourful map of the structure of the outer Solar System is providing new constraints on Neptune's migration.
Since Galileo, astronomers and planetary scientists work hard to draw accurate representations of planetary surfaces. Planetary mapping today is a tool of geological investigation, landing site selection and also a visual statement of our ever expanding horizon of discovery. From copper engravings to dynamic online maps, the technique of presenting planetary maps changed a lot. In this presentation I will show some early examples of how planetary maps can communicate unspoken preconceptions (no, its not the canals), and show how we mapped the Navua Valles, which may have episodically provided habitable environments on the inner rim of Hellas Basin on Mars. The talk is part of the International Map Year celebrations.