relativity

Tag archives for relativity

A scientific theory hasn’t really arrived until the cynical and unscrupulous find a way to use it to extract money from the credulous and gullible. This has posed a significant obstacle for general relativity, dealing as it does with gravity, which requires really gigantic masses to produce measurable effects. That makes it a little difficult…

Sean Carroll and Brad DeLong have each recently asserted that relativity is easier to understand than quantum mechanics. Both quote Feynman saying that nobody understands quantum mechanics, but Sean gives more detail: “Hardness” is not a property that inheres in a theory itself; it’s a statement about the relationship between the theory and the human…

The Physics Bus

SteelyKid, like most toddlers, knows a few songs, and likes to sing them over and over. Her repertoire is limited to “ABCDEFG” (the alphabet song, but that’s how she requests it), “Twinkle, Twinkle,” “Some man” (“This Old Man,” which I only figured out this weekend), and “Round and Round” (“The Wheels on the Bus”). I…

Counterfactual Physics: Lorentz Variance?

The theory of relativity takes its name from a very simple and appealing idea: that the laws of physics should look the same to moving observers as to stationary ones. “Laws of physics” here includes Maxwell’s equations for electricity and magnetism, which necessarily means that moving observers must see the same speed of light as…

What to Tell Your Dog About Einstein

“Hey, dude, whatcha doin’?” “Signing these contracts. I’m not sure why they need four copies, but they do.” “Contracts for what?” “The new book. Remmeber, the one we’ve been talking about these last few weeks? Sequel-of-sorts to How to Teach Physics to Your Dog? About relativity?” “Oh, yeah, that’s right! We’re doing another book! Where…

Since I was going to be down here anyway to sign books at the World Science Festival Street Fair, Kate and I decided to catch one of the Saturday events at the Festival. It was hard to choose, but we opted for the program on Hidden Dimensions: Exploring Hyperspace (Live coverage was here, but the…

Via Twitter, Michael Barton is looking for some good books about physics. I was Twitter-less for a few days around the period of his request, and this is a more-than-140-characters topic if ever there was one, so I’m turning it into a blog post. The reason for the request is that he’s going to be…

Accelerated Twins: The Answer

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…

Physics Quiz: Accelerated Twins

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…