Uploaded January 2016 | Updated September 2026, 9 hours ago

---

Dr. Robert Kirshner (Harvard University)
Nov. 11, 2015
In the past 20 years, astronomers have shown that the universe is not only expanding, but speeding up. In this talk, Dr. Kirshner, who was in many ways the "godfather" of these investigations, discussses the methods used to discover cosmic acceleration and presents the evidence that we live in a Universe that is only 4% matter like the atoms of the periodic table