energy
Tag archives for energy
Say Goodbye to Virgo…
Posted by Ethan on March 13, 2008 Aaah, the Virgo cluster. A huge cluster of hundreds of galaxies, and our closest large neighbor in the Universe. People have known for a long time that although Virgo is still redshifting away from us, it isn’t quite as fast as we would expect from the Hubble expansion rate of the Universe. Does this mean…
WMAP results: Cosmology from the CMB
Posted by Ethan on March 6, 2008 The cosmic microwave background is the radiation left over from the big bang. It’s very uniform, 2.725 Kelvin everywhere. We’re moving with respect to it, so there’s a doppler shift, and we see that as a dipole moment in the Temperature. When we subtract that out, we see variations on the order of 30 microKelvins!…
Q & A: Where does Matter Come From?
Posted by Ethan on March 4, 2008 I love The Straight Dope. For 35 years, people have written in and asked some of the most difficult-to-answer questions on any topic you can think of; the staffers, writing under the pseudonym Cecil Adams, do their best to get to the bottom of their questions. Well, they also have a message board, and I…
Q & A: What is Energy?
Posted by Ethan on February 25, 2008 Let me set the scene for you: I’m fresh off my Ph.D., teaching introductory physics at the University of Wisconsin. I’m trying to demonstrate how to turn potential energy into kinetic energy, and so I ask this simple question: What is Energy? And I get a stunned silence back from the room. One of those…
