SETI Institute Weekly Colloquium - Upcoming Speakers
New SETI Talks Location!
Starting Oct. 5, 2015 we will be holding the weekly colloquium series at the Microsoft Campus in Mountain view
1065 La Avenida St, Mountain View CA
Palaeomagnetic observations offer important insights into the origin of Earth's interior, but a detailed reconstruction of the underlying dynamics is not feasible. A practical alternative is to construct a stochastic model for the time evolution of the dipole field.
Slow changes in the field are described by a deterministic (drift) term, whereas short-time fluctuations are represented by a random (noise) term. Estimates for the drift and noise terms can be recovered from a time series of variations in the axial dipole moment over the past 2 million years. The results are used to predict a number of statistical properties of the palaeomagnetic field, including the average rates of magnetic reversals and excursions.
Dr. Buffet will explain how a physical interpretation of the stochastic models suggests that reversals and excursions are part of a continuum of time variations in Earth's magnetic field, arising from convective fluctuations in the core. Relatively modest changes the amplitude of convective fluctuations can produce large changes in reversal rates, including the well-known occurrence of superchrons lasting longer than 10 million years.
Astrobiology, the study of emergence of life and the its distribution in the Universe, addresses the most fundamental questions in science: "How does life begin ?" and "Are we alone ?" Over the last 20 years, we have discovered that planets are bountiful in the galaxy and that one in every five solar-type stars has a planet in the habitable zone. We have learned that extremophiles have spread to essential every niche – even the seemingly most inhospitable ones – on our planet. And we have learned that life started essentially as soon as conditions permitted, within some 200 million of the late heavy bombardment, or perhaps even earlier. This has resulted in a paradigm shift from "Life on Earth is unique" to the premise "life is widespread". As a result, searching for biosignatures in space has taken on a life by itself. In this talk, Dr. Tielens will summarize this shift in our thinking and the global processes that may have influenced the first steps towards life.
The focus in this talk will be on astrochemistry – the starting point of astrobiology – the chemical evolution that takes place in space where simple molecules are transformed into complex molecules and complex molecules are broken down to simple ones. This chemical dance of the elements produces a wide variety of organic compounds. I will review the processes that drive this chemical evolution in space, particularly in regions of star and planet formation. The focus will be on understanding the raw materials that are delivered to newly formed planets and their relationship to the building blocks from which prebiotic material was formed and biological systems evolve.
Shape Dynamics is a new theory of gravity which removes the notion of local relativistic time from the guiding principles of gravity in the universe. It is a very promising approach which has been shown to be equivalent to Einstein's Theory of General Relativity, without being embedded in time. It is inspired by adherence to Mach's Principle, which is violated by Einstein's theory.
Shape Dynamics provides new tools in the quest for a theory that describes quantum gravity.
In the first part of the talk Dr. Gomes will review some of the Machian motivations for shape dynamics and sketch its construction. In the second half, Dr. Gomes will talk about recent developments on black holes in this formulation, and discuss some positive aspects of its ongoing quantization program.