Archives for January, 2008

Dark Matter: Is it right in front of us?

Last year, I had just finished my Ph.D. studies, and had moved to Madison, WI to teach introductory physics at the University of Wisconsin. I was working on this paper, and when I submitted it, I got a phone call from New Scientist magazine’s space division. Fast-forward two weeks, and I find this article online,…

One of the worst teaching tools physicists use (and they almost all do it) is to tell students, There’s no such thing as centrifugal force. What can you do when the top physics education website says, “It is important to note that the centrifugal force does not actually exist. We feel it, because we are…

Brain-damaged arguments and Boltzmann Brains

Okay, so I got a question from my friend Tamara, who’s a high school teacher in my hometown of New York City. It concerns a recent article she read on the front page of the New York Times about something funny that us scientists are calling Boltzmann Brains. I’ve read this article three times since…

Question: The Milky Way to an outsider…?

I got a great question earlier today from my buddy Zrinka, and decided to figure out the answer for her, and also for myself. She asks: Ethan, is it possible to know, or better to say to imagine somehow how our galaxy looks from outside? What a simple-sounding question! After all, we know what the…

Evolution, creationism, and intelligent design are words that many people have extremely strong opinions about. Regardless of how you feel about why the laws of nature are what they are, which have evidently allowed us to exist, the evidence for the validity of the theory of evolution with one major mechanism being natural selection is…

One of the perks of being a postdoc at a place like the University of Arizona, one of the top places in the US for astronomy, is that we get a number of really interesting visitors. Today we got paid a visit by Tommaso Treu, an astronomer at UC Santa Barbara. He spoke to us…

MOND vs. Dark Matter

The first serious advocate of modifying Newton’s laws instead of postulating unseen (or dark) matter was Moti Milgrom, from whom today a new article appears on the astrophysics preprint archives. In particular, Milgrom asserts the following: MOND predictions imply that baryons alone accurately determine the full field of each and every individual galactic object. These…

First question!

Dave, one of my online chessplaying buddies, asked me this question (edited for appropriateness): Now this speeding up of the expansion of the universe: Do I understand correctly that one of the theories to explain why relates to “dark matter”? In real simple terms, what in the dark blue blazes is dark matter, and why…

What is that Background?

Taking a look at the background picture, and wondering what it is?  It’s the Bullet Cluster, also known to astronomers as 1E 0657-56. What’s so special about it? Well, these are actually two galaxy clusters that are in the process of merging, and are colliding with one another! Although this is very cool (and rare) in…

Setting up for the Blogosphere

In preparation for the launch of startswithabang.com, I am attempting to embed a video I had found on youtube, of the slow-motion ignition of a lighter. How does this work?  The video demonstrates that to make something very simple happen (to get a sustained, controlled flame out of a compact piece of equipment), a lot of…