Would LessWrong readers be interested in an intuitive explanation of special relativity?
Of course any scifi fan knows about Mazer Rackham’s very own “There and Back Again.” Why does that work? Special relativity!, I hear you say. But what does that actually mean? It probably makes you feel all science-like to say that out loud, but maybe you want a belief more substantial than a password. I did.
Relativity also has philosophical consequences. Metaphysics totally relies on concepts of space and time, yet philosophers don’t learn relativity. One of my favorite quotes...
″… in the whole history of science there is no greater example of irony than when Einstein said he did not know what absolute time was, a thing which everyone knew.”—J. L. Synge.
If I were to teach relativity to a group of people who were less interested in passing the physics GRE and more interested in actually understanding space and time, I would do things a lot differently from how I learned them. I’d focus on visualizing rather than calculating the Lorenz transforms. I’d focus on the spacetime interval, Minkowski spacetime, and the easy conversion factor between space and time (it’s called c).
I love to teach and write and doodle but I’m not sure whether LessWrong is an appropriate forum for this topic. I don’t want to dance in an empty or hostile theater dontchaknow.
I think intuitive explanations of physics are awesome. Though, there already seem to be several pretty great ones on the internet for special relativity. For example, see here, here, and here.
Are you aware of these other explanations? What would you do differently/better than them? Maybe there’s another topic not as well covered, and you could fill that gap? (These are just rhetorical questions to spark your thinking; no need to actually answer me.)
If you do pursue this project, then do let us know. Best of luck!
(Disclaimer: I’m not a physicist. My university work is in mathematics and cognitive neuroscience, not physics. So take my judgment about what constitutes a pretty great explanation of physics with as much salt as you like.)
Of all the youtube videos on the subject this is the best.
In a nutshell: I’ll go into more depth, there will be no video, and I’ll focus on world lines, Minkowski style.
Slightly less nutty: While those videos are easy snapping, I don’t think they actually do the topic any sort of justice. Actually the minute physics one is good, notice its use of world lines :D. It also passingly mentions invariance of distance in Euclidian space.
Right now my outline is roughly
How to interpret world lines. c=1 and time in meters or distance in seconds. Inertial frames and what those look like on spacetime plots.
Why speed of light is constant (Maxwell, experiment) and classical paradoxes that everyone learns to reason about by thinking about fast trains. Instead of vague thoughts about fast trains, we’ll look at spacetime diagrams where it is visually obvious that classical mechanics is wrong.
Lorentz transform from a spacetime perspective. Looking at a spacetime diagram all the seemingly disconnected consequences of SR, e.g. time dilation, length contraction, simultaneousstuff, are visually obvious and clearly caused by one thing: the lorentz transformation. Light cones.
Invariance of the interval, a little hyperbolic geometry, and then kapow: we can see how relativistic space travel works. We can see that cause and effect is enforced in this theory. I’ll mention the energy-momentum 4-vector because I think it’s interesting but it has less philosophical weight than the lorentz transform.
I’m expecting ~30 mins of reader time to learn and understand the material. There won’t be difficult math, although I will mention some hyperbolic stuff. I have another reason for wanting to do this, which is that I want people to understand world lines. They’re very useful for metaphysics discussions.
In my experience Hartle is easier and more engaging. It also relies on at most two years of undergrad math for non-math majors. Spivak, while fascinating, is a much more advanced book. Again, it is great for math majors, but there are much gentler ways to learn diff. forms and topology for a physicist.
Would LessWrong readers be interested in an intuitive explanation of special relativity?
Of course any scifi fan knows about Mazer Rackham’s very own “There and Back Again.” Why does that work? Special relativity!, I hear you say. But what does that actually mean? It probably makes you feel all science-like to say that out loud, but maybe you want a belief more substantial than a password. I did.
Relativity also has philosophical consequences. Metaphysics totally relies on concepts of space and time, yet philosophers don’t learn relativity. One of my favorite quotes...
If I were to teach relativity to a group of people who were less interested in passing the physics GRE and more interested in actually understanding space and time, I would do things a lot differently from how I learned them. I’d focus on visualizing rather than calculating the Lorenz transforms. I’d focus on the spacetime interval, Minkowski spacetime, and the easy conversion factor between space and time (it’s called c).
I love to teach and write and doodle but I’m not sure whether LessWrong is an appropriate forum for this topic. I don’t want to dance in an empty or hostile theater dontchaknow.
I would be interested in reading such a post.
Ditto
I think intuitive explanations of physics are awesome. Though, there already seem to be several pretty great ones on the internet for special relativity. For example, see here, here, and here.
Are you aware of these other explanations? What would you do differently/better than them? Maybe there’s another topic not as well covered, and you could fill that gap? (These are just rhetorical questions to spark your thinking; no need to actually answer me.)
If you do pursue this project, then do let us know. Best of luck!
(Disclaimer: I’m not a physicist. My university work is in mathematics and cognitive neuroscience, not physics. So take my judgment about what constitutes a pretty great explanation of physics with as much salt as you like.)
Of all the youtube videos on the subject this is the best.
In a nutshell: I’ll go into more depth, there will be no video, and I’ll focus on world lines, Minkowski style. Slightly less nutty: While those videos are easy snapping, I don’t think they actually do the topic any sort of justice. Actually the minute physics one is good, notice its use of world lines :D. It also passingly mentions invariance of distance in Euclidian space.
Right now my outline is roughly
How to interpret world lines. c=1 and time in meters or distance in seconds. Inertial frames and what those look like on spacetime plots.
Why speed of light is constant (Maxwell, experiment) and classical paradoxes that everyone learns to reason about by thinking about fast trains. Instead of vague thoughts about fast trains, we’ll look at spacetime diagrams where it is visually obvious that classical mechanics is wrong.
Lorentz transform from a spacetime perspective. Looking at a spacetime diagram all the seemingly disconnected consequences of SR, e.g. time dilation, length contraction, simultaneousstuff, are visually obvious and clearly caused by one thing: the lorentz transformation. Light cones.
Invariance of the interval, a little hyperbolic geometry, and then kapow: we can see how relativistic space travel works. We can see that cause and effect is enforced in this theory. I’ll mention the energy-momentum 4-vector because I think it’s interesting but it has less philosophical weight than the lorentz transform.
I’m expecting ~30 mins of reader time to learn and understand the material. There won’t be difficult math, although I will mention some hyperbolic stuff. I have another reason for wanting to do this, which is that I want people to understand world lines. They’re very useful for metaphysics discussions.
I’d be happy to assist, if you like. By the way, for a gentle introduction to general relativity for undergrads, I recommend Hartle.
I read my way through Schutz with relative (!) ease. Do you know how they compare?
Anyway right now I’m studying the math. Wandering through Spivak.
In my experience Hartle is easier and more engaging. It also relies on at most two years of undergrad math for non-math majors. Spivak, while fascinating, is a much more advanced book. Again, it is great for math majors, but there are much gentler ways to learn diff. forms and topology for a physicist.