A Greater Light to Rule the Day: The Sun, the Stars, and Climate Change

  • Jeffrey Hall | Lowell Observatory

Our seemingly steady Sun is a variable and violent place, with its activity rising and falling roughly every 11 years, most notably manifested as the sunspot cycle. However, solar activity is not just about spots: the Sun’s overall brightness changes as its activity rises and falls, and therefore the solar energy reaching Earth’s atmosphere is not constant. This has spurred many efforts to understand what effects this might have on terrestrial climate, including studies of the Sun itself as well as of stars similar to the Sun, the so-called solar analogs that allow us to infer the Sun’s behavior over centuries and millennia. Even more mysterious are the occasional lulls in the Sun’s activity cycle, when spots and other activity phenomena all but disappear; at least one of these lulls corresponds with a significant climate shift on Earth. In this seminar, we’ll take a look at the Sun over time, including our present understanding of its history and the interesting possibilities for the near future.

Speaker Details

Jeffrey Hall has served as Director of Lowell Observatory in Flagstaff, AZ, since June 2010. He joined the staff at Lowell in 1992 as a postdoctoral research fellow. He received a B. A. in Physics in 1986 from Johns Hopkins and a Ph.D. in Astronomy and Astrophysics in 1991 from Penn State. His research at Lowell has focused on solar and stellar activity cycles, with the goal of lending an astronomical perspective to solar influences on terrestrial climate. He presently serves as a member of the Northern Arizona Leadership Alliance and is former President of the Governing Board of Northland Preparatory Academy, a college-prep high school, as well as of the Board of Directors of the Flagstaff Symphony Orchestra.

Series: Microsoft Research Talks