Hi, I'm David Spergel, and
I'd like to welcome you to Princeton University's Coursera course,
Imagining Other Earths.
I'm a professor here at Princeton University where I'm chair of
the astronomy department.
By training, I'm a theoretical cosmologist, and a lot of my early work is
involved in microwave background, the leftover heat from the Big Bang.
I was one of the scientists deeply involved with
The Wilkinson Microwave Anisotropy Probe or WMAP.
We made a detailed map of the microwave background and
use that to determine a lot about the history of the universe.
We measured its age, 13.7 billion years, and
determine its composition, atoms, dark matter, dark energy.