Lecture 41: Dark Matter & Dark Energy

We are not made of the same matter as most of the Universe! This

surprising conclusion, that the ordinary matter we are made of (protons,

neutrons, and electrons) constitute only 13% or so of the total matter

in the Universe, the rest being in the form of Dark Matter. Further,

this dark matter is only about 30% of the combined matter and energy

density of the Universe, the remaining 70% of which appears to be a form

of Dark Energy that fills the vacuum of space and acts in the present

day to accelerate the expansion of the Universe. This lecture will

summarize the state of our understanding of Dark Matter and Dark Energy,

and look at the questions remaining to be answered in this active area

of current research. Recorded 2006 March 7 in 1008 Evans Laboratory on

the Columbus campus of The Ohio State University.