You may have seen some news reports over the last week or two saying that scientists had made a substance with the hottest temperature ever recorded — but that temperature was somehow below absolute zero, a negative temperature on the Kelvin scale. Weirdly enough, this is absolutely true….
Read more "What’s Cooler Than Being Cool?"Back to the Feynman lectures! The writing is quite beautiful — Feynman is very clear and readable, while still packing a great deal of information into a small space. There’s no way one blog post of reasonable length could cover all of the ground that Feynman does in each chapter. And this chapter is especially densely packed, because this chapter is setup. After some brief introductory remarks — and some philosophical comments on the nature of science that I’ll get to in a later post — Feynman gives the class a killer hook, and then uses that hook to reel the students (and readers) in through a quick introduction to many, many concepts that will come up again later in the text….
Read more "Feynman Lectures, Chapter I: The Most Important Idea in Science"I’m trying something new here, starting with this post: I’m blogging the Feynman Lectures on Physics, chapter-by-chapter (approximately). For those of you unfamiliar with the Feynman Lectures, they’re a classic set of introductory college physics lectures given by the great Richard Feynman 50 years ago at Caltech, compiled into book form. But despite their provenance, the books are not really introductory. They’re more like a rite of passage…
Read more "Blogging the Feynman Lectures"I’ve been out on the East Coast for the last two weeks, and I’m headed back west later today. While I was out here, my friends Yuko and Conrad put me in touch with Rym and Scott, who run GeekNights, and I ended up recording an interview with them. They posted it as a podcast, and you can listen to it here….
Read more "GeekNights Interview"The Second Law of Thermodynamics — entropy never decreases in a closed system — is among the more famous laws of physics. If you’re reading this blog, I’d be surprised if you’ve never heard of entropy before. You’ve probably also heard that entropy has something to do with disorder, and that the Second Law basically says that the universe tends toward disorder, but that’s not quite what the second law says — entropy isn’t really the same thing as disorder, though they’re related.
So what’s entropy? To answer that, I’ll steal a little bit from Kurt Vonnegut…
Read more "Entropy and Billy Pilgrim"Over the summer, the big physics news was the discovery of a new particle which is, in all likelihood, the Higgs boson. I’m not going to give a detailed explanation of what the Higgs is and how it was found — Bruce Bassett wrote a great post about that here, there’s a more detailed post here, and a set of more detailed posts here.
Instead, here’s an e-mail exchange I had with a friend about the Higgs — he had a question, and I answered it, but there’s a bit more to it than that…
Read more "Epistolary Higgs"This is a picture taken by a robot over one-and-a-half million kilometers away from the earth — over three times farther away than the moon — of the oldest light in the universe. This is impossibly faint light: it took a full year for the robot to collect enough light to take this picture. And even if it weren’t so faint, we wouldn’t be able to see this light with our eyes because it’s beyond the range of visible light, stretched by the expansion of the universe over the last 14 billion years…
Read more "Postcard from the Edge"Energy isn’t conserved. It can be — and is — created and destroyed. Your high school physics teacher lied to you. Or, more likely, your high school physics teacher was mistaken. And your college physics professor was probably mistaken too….
Read more "Getting Nothing for Something (and Vice Versa)"Apparently, a team of scientists working at CERN have found evidence suggesting that neutrinos can travel faster than the speed of light. While this has turned a few heads, the wide consensus is that this will probably turn out to be some kind of systematic error and not a real effect. Extraordinary claims require extraordinary evidence, and this evidence has to pass a hell of a lot more tests — and be reproduced by a lot more people — before anyone, including the team who produced the results, will feel comfortable saying that they’ve found a way around the ultimate speed limit. But why would this be such an extraordinary claim? The speed of light is a hard limit in Einstein’s relativity, but why?…
Read more "Neutrinos and Flux Capacitors"