Winter 2014

02/18/2014 | Powering Cosmic Processes by Star Light -- Sally Oey (U-M Astronomy)

The ultraviolet radiation from massive stars is a powerful form of energy that irradiates many parts of the universe. This energetic starlight powers star-forming nebulae on small scales, and dissipates cosmic gas on the largest scales.

02/15/2014 | Where the Solar Wind Blows -- Susan Lepri (U-M Atmospheric, Oceanic and Space Sciences)

The Sun’s hot, gaseous corona continuously expands at supersonic speeds, filling the solar system with magnetized plasma. Through the solar wind and the plasma carried along with it, the Sun touches and interacts with each of the planets and other bodies in the solar system. We will discuss how the solar wind is born and how it influences objects in the solar system.

02/22/2014 | Sculpting the Universe -- David Weinberg (Ohio State University)

Since 2004, David Weinberg has been collaborating with artist Josiah McElheny on the design of cosmologically inspired sculptures, which represent the history of the expanding universe and the formation of structure within it. In this talk, he will describe these sculptures and the astronomical concepts that underlie them, which include the nature of cosmic expansion, the transition from an opaque universe to a transparent universe, the formation and clustering of galaxies and quasars, the seeding of cosmic structure by primordial fluctuations in the early universe, and the possibility that our observable cosmos is only an "island" in a larger "multiverse." The sculptures that have emerged from this collaboration have been exhibited in galleries and museums across the U.S. and Europe.

03/15/2014 | Cell Membranes: Using Physics to Function -- Sarah Veatch (U-M Physics)

The outer boundary of the cell is made up of lipids and proteins whose primary role is to protect the cell while selectively transmitting information and nutrients across its boundary. Cells have come up with many clever tricks to accomplish these vital functions, one of which is to tune its membrane composition near a phase transition, allowing cells to exploit the unique physical properties of this thermodynamic state. Professor Veatch will discuss a few examples where cells appear to use membrane lipids to organize and regulate the activity of membrane proteins.

03/22/2014 | The Origin of Life: Chemistry As The Driver of Our Evolution -- Nils Walter (U-M Chemistry & Biophysics)

Life has an origin shrouded in mystery. Ever since the first human developed an awareness of self did we wonder where we came from. Modern science has traced our origins to the beginning of Earth as a planet with liquid water, giving rise to a primordial soup that contained all the ingredients of a modern organism. How these chemicals assembled into ever more complex life forms can be understood as an inevitable result of an energy-driven Darwinian evolution from molecules to single cells, the human body and even modern society. This lecture will sketch out a best-guess scenario of the stages of this journey and suggest that ancient “molecular fossils” from it still survive in our body’s cells today.

03/29/2014 | Particles and the Nature of All Things -- David Kaplan (Johns Hopkins University)

Professor Kaplan will describe what is known about the laws of the nature of matter at the deepest level -- quantum field theory -- and what it 'means' to discover new particles. He will describe the structure of our current theory of nature, explain briefly the Higgs particle and phenomenon, and describe what sort of breakthroughs in particle physics we are pushing towards in the future.

04/05/2014 | Results from Randall Lab: Graduate Students Share Their Research -- Benjamin Lawson (U-M Physics), Timothy Olson (U-M Physics), Jenna Walrath (U-M Physics)

Benjamin Lawson: Materials can be categorized and described in many different ways - a familiar example is whether they are conductors (can carry electricity) or insulators (cannot carry electricity). Ben will discuss the search for novel materials that do not fit into either of these categories and talk about the properties of some completely new types of matter.

Timothy Olson: The fundamental forces and laws of physics can be thought of as arising from special symmetries of nature. Tim will present a new way of describing some of those symmetries geometrically using volumes of higher-dimensional shapes.

Jenna Walrath: Thermoelectric materials directly convert heat to electricity without any moving parts, offering a way to reliably recover waste heat in systems ranging from power plants to cars. Jenna will explain thermoelectric generators and describe her work studying thermoelectric materials on a nanometer scale with the goal of better understanding methods for increasing efficiency.

04/12/2014 | A Viking Navigational Aid: Polarized Light -- Vasudevan Lakshminarayanan (U-M Physics Visiting Scholar)

The Vikings navigated the north Atlantic and landed in the new world about three hundred years before the invention of the magnetic compass. How could they have done this? The answer lies in the ‘sunstone” referred to in Viking legends. It is possible that the sunstone, a calcite crystal could have acted as a depolarizer and enabled the Vikings to navigate. Professor Lakshminarayanan will discuss polarization of light and birefringent crystals as well as the Haidinger brush phenomenon.