Relativity

I want to like this book more than I do. As a general matter, this is exactly the sort of science book we need more of. As you can probably guess from the title, Why Does E=mc2? sets out to explain Einstein's theory of relativity, and does an excellent job of it. It presents a clear and concise explanation of the theory for a non-scientific audience, using no math beyond the Pythagorean Theorem. I picked this up partly as research of a sort-- if there is ever a How to Teach Physics to Your Dog 2: Canine Boogaloo, the most obvious topic for it would be relativity, which I mention a few times,…
Yesterday's post on a variation of the "Twin Paradox" with both twins accelerating was very successful-- 337 people voted in the first poll question, as of a little before 9am, and the comments to the original post are full of lively discussion. That's awesome. I wish I could take credit for it, but the problem posed is not original to me. It comes from a 1989 paper in the American Journal of Physics, which also includes the following illustration setting up the situation: The article contains a full explanation, and also the following figure illustrating the result: The correct answer is…
Just about everybody has heard of the Twin Paradox in relativity: one twin becomes as astronaut and sets off for Alpha Centauri, the other remains on Earth at mission control. Thanks to time dilation, the two age at different rates, and the one who made the trip out and back ends up younger than the one who stayed behind. Of course, the paradox is not that the two twins have different ages-- rather, it's that from a simple approach to special relativity, you would think that each twin should see the other's clock running slow, since it seems like getting into a rocket and flying off into…
One of the few sad things about the recent American domination of physics (says the American physicist) is that new physical phenomena are now mostly given boring, prosaic American English names. Don't get me wrong, I like being able to pronounce and interpret new phenomena, but when the pre-WWII era of European dominance faded away, we lost those awesome German names. Like, for example, zitterbewegung, a word that just demands an exclamation point: Zitterbewegung! The phenomenon it describes, ironically, comes out of work by the great English physicist and odd duck Paul Dirac. Dirac's…
Thony C has a post about the Great Man theory of science spinning off some thoughts about Darwin by ex-ScienceBlogs silverback John Wilkins. As Thony writes: Now you may ask why I as a historian of Renaissance mathematics should comment on a blog post about a 19th century work of biology and its author? The answer is quite simple; everything that John says about Darwin and his book can and should be applied to Copernicus, Kepler, Galileo, Descartes, Newton and a host of other scientist from the early modern period and their works. Nothing that any of these scholars did or wrote existed in a…