For 14 billion years, cosmic microwave background radiation has filled the universe like an after-image of the big bang. This radiation is the oldest light we can see; because it bears the imprint of the universe's infancy, it can help answer such questions as how the universe began and what its future holds.

John Carlstrom's quest to understand this radiation has driven him to work at the coldest and driest desert on the planet, the high Antarctic plateau, where he leads the 10-meter South Pole Telescope project at the National Science Foundation's Amundsen-Scott South Pole Research Station. The telescope is the largest ever deployed in Antarctica, and Carlstrom uses it to make detailed measurements of cosmic microwave background radiation.

Carlstrom will share his research and experiences in a free public talk as this year's Hans Bethe lecturer. His talk, "Exploring the Universe From the South Pole," will be held Oct. 17 at 7:30 p.m. in Cornell's Schwartz Auditorium, Rockefeller Hall.

Other events during Carlstrom's visit will include a physics colloquium, "Cosmological Physics With the Cosmic Microwave Background: New Results From the South Pole Telescope," Oct. 15 at 4 p.m. in Schwartz Auditorium; an astronomy colloquium, "New Measurements of the Sunyaev-Zel'dovich Effect: Constraining Cosmology Through the Growth of Structure," Oct. 18 at 4 p.m. in Room 105, Space Sciences Building; and a LEPP Journal Club talk, "CMB Status and Future Directions," Oct. 16 at 2 p.m. in Room 401, Physical Sciences Building.

Carlstrom is the Subramanyan Chandrasekhar Professor of Astronomy, Astrophysics and Physics at the University of Chicago, as well as deputy director of the Kavli Institute for Cosmological Physics. He is a member of the American Academy of Arts and Sciences and the National Academy of Sciences. He received his Ph.D. in physics from the University of California-Berkeley in 1988 and has since received several awards, including a MacArthur Fellowship in 1998.

The Bethe Lectures, established by the Department of Physics and the College of Arts and Sciences, honor Hans A. Bethe, Cornell professor of physics from 1936 until his death in 2005. Bethe won the Nobel Prize in physics in 1967 for his description of the nuclear processes that power the sun.

Linda B. Glaser is staff writer for the College of Arts and Sciences.