Hearts of Darkness: Black Holes in Space

Dr. Alex Filippenko (University of California, Berkeley). Black holes are regions of space where gravity is so strong that nothing, not even light, can escape! No longer confined to the imaginations of science-fiction writers and theoretical physicists, black holes have recently been discovered in large numbers by observational astronomers. Learn about the remarkable properties of these bizarre objects from one of the finest explainers in the field of astronomy.

Related Links
Books and Films - Black Holes

Dark Energy and the Runaway Universe

Observations of very distant exploding stars show that the expansion of the Universe is now speeding up, rather than slowing down due to gravity as expected. Over the largest distances, our Universe seems to be dominated by a repulsive "dark energy" of unknown origin that stretches the very fabric of space itself faster and faster with time.

About the Lecturer
Alex Filippenko (NAS), University of California, Berkeley, was a member of both teams that discovered in 1998 the accelerating expansion of the Universe, driven by "dark energy."

Related Links:
Dark Matter and Dark Energy