Hello, everyone. Welcome to the March 2021. Ask me anything episode of the Mindscape podcast. I'm your host, Sean Carroll.

And as most of you know, this is something that is made possible by donations from patrons on Patreon.

So once a month we do an episode where patrons get to ask questions and then I will try to answer them.

And then a couple of weeks later we'll get the transcript made and release the results into the wild and to the public.

So thanks to the patrons for supporting this and the number of patrons and the number of questions has been growing.

So we finally reached a point where rather than just trying to answer every question, I will pick some subset of the questions to answer those.

And so therefore, this is the first time we've been doing it. And we'll see how it goes. Let me know. Please do feel free to chime in.

Your opinion says to how it's going. How do I choose which questions to answer? You might ask.

So it turns out that well, you know, I'm still trying to answer a lot of questions. I don't want to just pick five questions out of 100 or 200 and answer those.

I want to give as many people a chance to ask something as possible. But it's a weird, unpredictable set of criteria that I use actually and maybe not even completely explicable or articulatable.

Some questions, for example, were perfectly good questions. Most questions are really good in some contexts, but I just don't have anything interesting to say about them. So I skipped those.

And some of those were sort of fun questions like what's your favorite dessert? Well, I don't have a very fun favorite dessert. I don't know ice cream, apple pie, something like that.

So it just didn't seem to be the kind of thing to give myself time to explicitly don't want to have nothing to say. So oftentimes, if I don't pick your question, it's more a comment on me than a comment on your question.

And other questions are just also interesting, but in some realm that I either don't have anything to say about or I've said too much about already. And I'm interested in saying other things.

So, but I think it'll work out pretty well. Anyway, you'll let me know, right? We saw plenty of questions to get through. So let's go.

So before we officially start, let me have some words on time dilation and special relativity and those kinds of questions, because I actually called them out in the little call for questions.

And I mentioned that these are not my favorite kinds of questions. And yet, somewhere asked fewer than usual. But so let me, let me rather than answer them, explain why these are not my favorite questions, because it's not like they're, again, bad questions are perfectly good questions.

And it's certainly these questions are asked by people who are trying better to understand difficult physics, right? So that's the kind of thing that I want to encourage.

So it's a specific genre of question that I just get tired of answering myself, because there is some kind of phase transition your brain goes through when you learn relativity from the point where these questions about time dilation and, and either in special relativity or in general relativity,

whatever they go from being just completely ineffably mysterious to like completely obvious, let you get it, right? You, you like it suddenly clicks and you understand it. And once you reach that point and sort of articulating it over and over again, you just find yourself repeating yourself and it's less interesting.

So let me try to sort of give my once and for all answer to how one should think about this kind of thing. You know, I noticed it again on Twitter recently when we just recently had the lander, the perseverance lander landing on Mars.

And someone, you know, we know that Mars is seven light minutes away, roughly speaking. So it depends on the place it is and the orbit and so forth. But there's a delay from the signal getting from there to us.

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