Sunday, November 24, 2024

My new favorite science YouTuber - FloatHeadPhysics

I've been a big fan of science Youtubers for several years now. I even did a couple of blog posts on them in the past. PBS Spacetime was my favourite for a long time until they started running out of ideas. I discovered FloatHeadPhysics a few months ago and just decided today that Mahesh Shenoy is my new favourite science YouTuber.

I highly recommend any videos he has on special or general relativity. Mahesh is a superb communicator. He doesn't just explain the different phenomena; he strives to explain them in a way that makes them intuitive so they are not only easy to understand but they make sense as well. Before I watched his videos, there were some things I understood (or believed) intellectually but didn't understand (or know) in my heart. For example, gravity is sometimes explained by saying the earth is accelerating upward. I believed that because it's what the experts said, but it made no sense to me since the earth wasn't expanding. But I saw a video the other day where he explained it in a way that was intuitive and made sense. He made the light come on for me.

One of the first videos of his I saw was on the Twin Paradox. I had seen a ton of videos on this subject, and it seemed like multiple people gave different explanations. Most people resolved the paradox by pointing to the fact that the twin who left and came back had to experience acceleration when they changed direction, but Don Lincoln at FermiLab made two videos I found convincing arguing that acceleration had nothing to do with the solution. Then Sabine Hossenfelder (I think--my memory isn't perfect) made a video insisting that the solution involved acceleration, and Don Lincoln responded by saying, "We're basically saying the same thing," when they clearly were not. Well, I watched FloatHeadPhysic's video on the subject, and so far it was the best video of all the videos I've seen on the Twin Paradox.

Another science YouTuber I discovered since my last post on this subject that I wanted to mention because it's worth drawing attention to is Space Mog with Maggie Liu. She also has some excellent content and explains things really well.

Oh, and there's also GeoGirl with Rachel Phillips. I don't remember if I mentioned her or not. I got really interested in geology in the 10th grade. I've been insterested in astronomy for as long as I can remember, and my high school offered an astronomy class that was one semester. To take astronomy, you had to also sign up for geology for the other semester. I wasn't that interested in geology until I took the class. It was awesomer than I expected. It's been a long time since I've really gotten into the topic, but Rachel's channel has re-awakened my interest. Her videos are outstanding because she goes into a lot of detail and uses powerpoint.

EDIT 11/26/2024: Somebody in the comments didn't agree with me when I said Don Lincoln and Sabina Hossenfelder were not saying the same thing about the resolution to the Twin Paradox, so here are the videos I was talking about so you can judge for yourself.

Don Lincoln/Fermilab's first video on the Twin Paradox

Don Lincoln/Fermilab's second video on the Twin Paradox

Sabina Hossenfelder's video on the Twin Paradox

Don Lincoln/Fermilab's response to Sabina Hossenfelder

Mahesh Shenoy/FloatHeadPhysics' video on the Twin Paradox

Mahesh Shenoy/FloatHeadPhysics' second video on the Twin Paradox (I just saw this one today. Mahesh agrees with Don that although acceleration is necessary to cause a change of reference, the solution to the paradox doesn't lie in the acceleration per se. According to Mahesh, the solution lies in the relativity of simultaneity. His explanation makes a lot of sense to me.)

It looks like I was a little skeptical when I saw Don's first video. I left a comment saying, "But from the point of view of the traveler, if they can always consider their own frame of reference stationary, then it isn't them who has existed in two reference frames. It's the person who supposedly didn't travel who existed in two reference frames."

I left another comment on his second video saying, "I've watched both of your videos, and I still don't get it. If Jim is station on earth, and Bob goes out, then comes back in again, then from Jim's frame of reference, he's in one frame of reference, and Bob is in two--outbound and inbound. But from Jim's frame of reference, wouldn't he be in one frame of reference and Jim in two since Jim moves away from him, then toward him?"

I left a comment on Don Lincoln's third video saying, "Maybe I'm stupid, but I don't agree with this at all. I think you and Sabine ARE saying something different. Sabine says that acceleration is what solve the paradox, not because acceleration is necessary to create two reference frames, but because of the acceleration itself. You deny it's the acceleration itself and say it's merely because of the two reference frames."

As a bonus, here's another video I saw seven months ago directly responding to Don Lincoln and explaining where he thinks Don went wrong. I left a comment on this video saying, "I remember trying to figure out the twin paradox, running into Don Lincoln's video after watching several others, and thinking, 'Finally! I understand!' But I guess I didn't understand. Of course not being a physicist myself, I'm still not sure. If the experts disagree, how can I adjudicate between them?"

For now, I think I'm going to go with Mahesh' explanation because his makes the most sense to me.

This is such an interesting topic to me! The whole reason I delved into the Twin Paradox several years ago was because of NaNoWriMo. NaNoWriMo is this movement where people commit to writing a 50k word novel within the month of November. I thought it would be fun to do, and I had a story cooking in my head for a long time. It was a time travel story. In the first chapter, I talked about how the main character came up with the idea for a time machine. I got bogged down talking about special relativity when I realized there was some stuff I didn't understand. So I went on YouTube and started watching Twin Paradox videos. I never did complete my novel because, as you can see, I hadn't found a solution to the Twin Paradox I was confident about enough to include it in my novel.

3 comments:

Anonymous said...

Lincoln simply said that the fundamental difference was "two frames vs. one." Sabine said that "acceleration is key." These seem to be the same thing, until you realize that "acceleration is what causes you to enter different inertial frames." The two-frame answer is the deepest and most fundamental, but you can't do that without acceleration and acceleration means multiple frames.

It is in this manner that they are identical. But, if you need to pick one because...I don't know...it's difficult to see that there are equivalent explanations for the same observation...then the "two-frame" one is more correct.

Anonymous said...

Typo/hastiness correction "these seem to be the same thing" -> "these seem to be different things". Apologies.

Sam Harper said...

I agree with you that you have to accelerate to change your frame of reference, but Lincoln explicitly said the acceleration had nothing to do with the solution. That was the whole point of his original two videos on this topic. He attempted to show that by imagining the traveling twin as two different people--one going out, and one coming in, so that neither one of them had to CHANGE direction. The point of his illustration was to eliminate acceleration and arrive at the same conclusion merely because there were two different frames of reference involved. So I don't buy that he and Sabine were giving the same explanation. They definitely were not.