Science at Cal - Jeffrey Silverman - Exploding Stars, Dark Energy, and the Runaway Universe

Some of the brightest and most fascinating objects in the Universe are exploding stars known as supernovae. These colossal outbursts result from the deaths of stars and for a time can outshine the entire galaxy in which they are found. Observations of very distant supernovae provided the first evidence that our Universe is accelerating in its expansion, likely due to a repulsive and mysterious "dark energy." It was these observations that were recently awarded the 2011 Nobel Prize in Physics.

Dr. Jeff Silverman studies and observes supernovae with Prof. Alex Filippenko, and recently received his PhD from UC Berkeley. He was born and raised in Anaheim, CA just down the street from Disneyland and graduated from Rice University in Houston, TX in 2005. In the Fall, Jeff will be returning to Texas as a postdoctoral researcher at the University of Texas at Austin.

 

Science at Cal - Jason Dexter - Black holes - What do they look like?

Despite their dark name, black holes power some of the brightest objects in the Universe. Jason Dexter will discuss the observational evidence for the existence of black holes, the types of black holes that can be seen and the reasons why. What is an accretion disk that forms around a black hole? Jason will attempt to answer this question and others, as well as describe what the supermassive black hole at the center of the Milky Way will look like when Astronomers manage to image it in the near future.

Jason Dexter got his Ph.D. from the University of Washington, and is now a postdoctoral fellow in the Astronomy Department at UC Berkeley. He is interested in astrophysical black holes, and what we can learn from the light emitted by gas falling into them.


 

Hazel Bain: The Sun - A Star in our Own Backyard

The Sun offers us a unique opportunity to study the inner workings of these giant balls of plasma. Starting at the core, Dr. Bain talks about the processes occurring at the different layers of the Sun: From sunspots observed in the photosphere, which vary characteristically with the solar cycle, to explosive flares and coronal mass ejections, which release huge amounts of energy into the corona. Finally she talks about the effect these eruptive events have on the Earth's atmosphere, and how the particles accelerated at the Sun produce the displays of lights known as the Aurora Borealis and the Aurora Australis.

Other Science@Cal lectures

Beate Heinemann: The Quest for the Higgs Boson at the Large Hadron Collider

Beate Heinemann presents a public talk at UC Berkeley on January 21st, 2012, as part of the Science@Cal Lecture Series.  She describes the LHC and its experiments, the relevance of the Higgs boson and the current state of the experimental searches.

Other Science@Cal lectures

Spencer Klein: Neutrino Astronomy in Antarctica

Spencer Klein presents a public talk at UC Berkeley on August 21, 2010, as part of the Science@Cal Lecture Series .

For the past 50 years, scientists have been studying cosmic-ray air showers consisting of billions of particles, produced when an ultra-high energy particle strikes the earth.  Despite enormous effort, we still have not found the cosmic accelerators that create these particles.

One way to find these accelerators is to search for the neutrinos that they produce. Neutrinos travel cosmic distances in a straight line, interact weakly, and can reach us even through dust clouds or other obstructions. Because of their weak interactions, huge detectors are required to observe these neutrinos. Antarctic ice is an attractive material, and several neutrino detectors are being built there. The 1-cubic-kilometer IceCube neutrino observatory is already in partial operation at the South Pole. The proposed 100 cubic-kilometer ARIANNA detector will be located on the Ross Ice Shelf, about 20 miles offshore.

Other Science@Cal lectures

Lucianne Walkowicz: Magnetic Stars, Space Weather and Life: Stellar Activity and its Effect on Planets

Lucianne Walkowicz presents a public talk at UC Berkeley on June 19, 2010, as part of the Science@Cal Lecture Series .

Sunspots are some of the oldest astronomical phenomena observed by human beings. These "freckles" on the the face of our Sun may look innocuous, but they are actually the footprints of huge magnetic loops that protrude from our star. These loops sometimes twist and snap, causing spectacular solar flares that send radiation and energetic particles hurtling towards Earth. These flares are responsible for beautiful aurorae, but they can also cause the troubling disruption of satellites and other infrastructure. Similar phenomena are observed on many other stars in our Galaxy, with some stellar flares being even more powerful than those of the Sun. What is it like to be a planet around those stars? How do flares and starspots affect a planet's ability to support and sustain life?

Other Science@Cal lectures