New video incoming! We'd love your feedback
Added 2024-04-26 14:06:15 +0000 UTCComing soon: our video on black holes, white holes, wormholes - and what Einstein got wrong. Here is a work-in-progress version. We'd love to hear your suggestions as we put the finishing touches to the video.
Thank you!
Casper and Team Veritasium
Comments
I’m hoping this is an appropriate place for this question. When the Moon is directly overhead, do I weigh less on Earth? Of course, my mass is unchanged, but would a spring scale change indicate a change in weight? And, if yes, then how sensitive a device could detect the change in weight.
J W
2024-06-10 20:48:39 +0000 UTCWOW! Love it! More like this please!
Raffi Minassian
2024-04-27 15:49:56 +0000 UTC15:30 Do not say "... fourteen times smaller" but instead "... one fourteenth..." Or " ... seven percent..."
Gregor Shapiro
2024-04-27 14:10:23 +0000 UTCThank you for these detailed notes John!! - Casper
Veritasium
2024-04-27 03:54:56 +0000 UTCReally enjoyed the video, great work! “Why can’t we have two?” I like that 😀
Universalmatt
2024-04-26 22:21:30 +0000 UTCJust checked out ScienceClic's Channel and WOW does he have some good explanations there
Thaddeus Paul Hatfield
2024-04-26 22:04:07 +0000 UTCI think there is too much information here for one video. There are many interesting ideas in this video but I feel like the explanation of them will be too "news" like. I suppose you could call it a introduction to Space Time and then expand on some of the ideas in later videos but again I feel like most people are going to walk away going what was all that.
katgod
2024-04-26 21:25:18 +0000 UTCCallout to the animations provided by ScienceClic. Those were amazing. @15:55 "People realized that if you choose a different coordinate system by doing a coordinate substitution, then the singularity at the event horizon disappears." Explain: Why? The event horizon line is still there. Did the explanation have to be cut for time and be left to audience imagination? Suggest: Maybe mention, "we'll get back to this later" in anticipation of ~19:55? @16:18 "...it just resulted from a poor choice of coordinate system..." Quality: Audio sounds like it cut off in the middle of the sentence. @20:14 "And since the future always points up in this map, it tells us that the singularity is not actually a place in space, but instead it's a moment in time..." Explain: Why? Is this statement premature because of the explanation @21:16? Previously, it was stated that the future is a cone, not simply straight up, so for the singularity line to be a point in time, it would have to evenly cut off both sides of the "future time" cone...wouldn't it? I think. This graph is hard to understand. Label: The "Kruskal Time" label might need to be "Kruskal-Szekeres coordinate system". When I search for "Kruskal Time", all I get are search results for the time complexity of the Kruskal algorithm to navigate graphs, which is definitely not this topic. @21:25 "...so the singularity is at r=0...this line is at r=4m, and this is infinitely far away." Label: Suggest adding the notations as you mention them, especially for "this" lines. Explain: The term "m" wasn't covered yet, but it's important now. Should it have an introduction earlier? @22:30 "If you're inside this region, you can send signals to the universe, but no matter where you are in the universe, nothing can ever enter this region. So, things can come out, but never go in." Explain: Why does this only go one direction? What is it about the dashed line between the "black hole's past" region (not labeled at this point, so I'm trying to describe it) and the universe that only goes one direction? Is this referencing something earlier? If so, could you repeat it here for clarity? @24:10 "Now, we've been showing thing ejecting to the right, but they could just as well be ejected to the left." Label: Suggest lines indicating direction to make this flow better. The animation showing things going into the blue region focuses attention there, so when you said "to the left", I thought that you were reversing the direction of ejection, but it turned out you were still talking from the perspective of the "black hole's past" region. @24:19 "This line is not at infinity..." Label: What line? @24:45 "The only downside is that we'd soon both end up in the singularity." Question: What is "soon" if you're past the event horizon? Does that concept still work? Is time actually compressed to the viewer within the singularity, or does it only appear to be compressed to an outside observer? Maybe just interrupt the animation with a screenful of a text thought dump about this? @25:07 *explanation of negatives solving the equation* Question: Does the fact that negatives solve the equation necessarily mean that this solution exists? Is that beyond the scope of this video? @26:41 "That's what you get when you push this map to its limits..." Suggest: Don't leave this statement here, but add something to keep attention on the fact that you're not done with it (revealed @31:44). @27:03 "Now this line is at constant Kruskal time." Explain: What is "Kruskal time"? I saw it on warped graph @20:14, but no explanation was given. It's clearly relevant now. Can we get an introduction before referring to it? @29:15 "The black hole now consists of several layers." Suggest: Add a callback mention that these layers are not gradations, but hard boundaries as the result of the more complicated Roy Kerr solution dealing with the same "divide by zero" problems that David Hilbert had discovered with Schwarzschild's solution. @32:44 *zooming out animation* Explain: Stray extra lines that pop in and out during the animation. Are these intentional, or accidental geometry that didn't get cleaned up? @33:54 "...an immortal astronaut inside a Kerr universe..." Explain: A what universe? @34:10 "This concentration of energy then creates its own singularity, sealing off the ring singularity and beyond." Explain: Why does the infinite flux of energy make a singularity? The explanation at the beginning of the video focused on spacetime being distorted by mass and eventually on singularities being created by mass. Yes, energy can be converted to mass and vice versa, but why would it here? ...unless they are the same thing manifesting different forms, which might be beyond the scope of this video. Or can a singularity be created by something other than mass?
chromicacid
2024-04-26 19:31:53 +0000 UTCAt 00:02:08 the direction of the lunar and earth orbits seem incorrect. If you show a recognizable continent, Africa, the subsequent orbits should be quite different.
Gregor Shapiro
2024-04-26 18:22:20 +0000 UTC12:52 ... As an inside joke, the inclusion of '37' is funny. But unless you're indicating that _information_ is also something that can't enter, then it might be confusing. And if you _are_ indicating that information also can't enter, it might need a little more explanation.
Kimberly Green
2024-04-26 18:00:12 +0000 UTCUnfortunately still there are so many placeholders that it's hard to evaluate whether the planned graphics will clarify the verbal explanations. Around 21:25, there are a few explanations of the Penrose diagram where Derek talks about "this line" or "these lines", but no arrow or other effect shows which of the lines in the diagram he actually refers to.
Lionel Pöffel
2024-04-26 17:53:42 +0000 UTCThe curvature of spacetime is usually depicted as a hole with width, height, and depth, where the depth is the gravitational pull that changes as you approach it from the other 2 dimensions. But a black hole's gravitational "depth" changes as you approach it in 3 dimensions, and now I need 4 dimensions to imagine it and my brain breaks. I see the animation @17:35, and that's a good attempt, but it's still stuck in 3 dimensional animation.
chromicacid
2024-04-26 16:54:29 +0000 UTCWhat aboug Hawking radiation? Can it be that the white hole solution describes a hawking radiation? Can it be that the Penrose diagram actually wrapa around? Whatever "reaches" the top line it wraps around and comes into the White hole starting from the bottom? And we see it as Hawking radiation.
Bartosz Błaszkiewicz
2024-04-26 16:27:36 +0000 UTCA little bit before 06:00 "Spacetime is flat". You could make it a little bit clearer that this means "at large scales" or "barring the effect of matter". Right now this statement seems to contradict the latter "matter curves spacetime". So how is it? Is it flat? Or curved?
Bartosz Błaszkiewicz
2024-04-26 15:40:22 +0000 UTC
