mea1top Posted June 7, 2019 Posted June 7, 2019 (edited) Just curious - as a non-science major - the Nicholas Roeg film has a scene in which Marilyn Monroe explains special relativity to Einstein. But I have a feeling the explanation is wrong - please see script below - wouldn't, on this basis, each observer conclude that the other observer had the same time reference - the only issue being the amount of time light takes to reach each one, which can be accounted for by each? I've had to attach it as the script extract is too long otherwise. Thanks for your views! Script: Insignificance.docx Edited June 7, 2019 by mea1top typo
Strange Posted June 7, 2019 Posted June 7, 2019 It is very much simplified, but it seems accurate. The speed of light is independent of the speed of the source. So the light from both trains will spread out at the same speed.
pzkpfw Posted June 7, 2019 Posted June 7, 2019 Post #49 here contains some great animations that I think are relevant: https://www.physicsforums.com/threads/the-velocity-of-a-moving-frame-of-reference.972860/page-2 1
Janus Posted June 7, 2019 Posted June 7, 2019 50 minutes ago, mea1top said: Just curious - as a non-science major - the Nicholas Roeg film has a scene in which Marilyn Monroe explains special relativity to Einstein. But I have a feeling the explanation is wrong - please see script below - wouldn't, on this basis, each observer conclude that the other observer had the same time reference - the only issue being the amount of time light takes to reach each one, which can be accounted for by each? I've had to attach it as the script extract is too long otherwise. Thanks for your views! Script: Insignificance.docx It seems accurate to me, up to that point, the only problem that I see is that That the text after "Not only that..." should be clearer that the speed at which each of each train would measure that sphere of light as expanding at would be c, relative to itself. The red train measures both lights expanding away from itself at c, and the Green train measures both lights as expanding away from itself at c. (this also means that each train would measure the light's speed with respect to the other train as being something other than c. ) So for example, according to the Red train after 1 microsecond, the edge of the beam will be ~300 meters in front of him. Let's say that he is traveling at 0.5c relative to the Green train in the the same direction as the beam. Then the Green train, after 1 microsecond would measure the beam as being ~300 from him, but only ~150 meters ahead of the Red train.
md65536 Posted June 7, 2019 Posted June 7, 2019 No, Insignificance gets relativity wrong. However the quote above was cut off right before it gets bad. https://www.springfieldspringfield.co.uk/movie_script.php?movie=insignificance Quote Not only that... it's time as well. You got a watch? 'Cause you're gonna need it. Now, we have to imagine this room... is the entire universe. And we begin together someplace... in space-time... and we synchronize it. What does your watch say? I travel away from you at a hell of a speed. Say, one-fifth the speed of light. And I travel for five minutes, and it gets me here.Now, I look at my watch. It says 20 minutes past 8:00. But it's not very reliable... so I look across the universe... to check with your watch.- And what does your watch say? - Twenty minutes past 8:00? Not to me it doesn't.It says 19 minutes past 8:00... because 20 minutes past 8:00 hasn't reached me yet. It takes a minute for me to see your watch... because it takes a minute for the light to reach me.See? So your watch is getting slower and slower. And now comes the thousand-dollar question. Remember, if you look at my watch... it's gonna take a minute for it to reach you too. - So now what do you say my watch says? - Nineteen minutes past 8:00. Which means you say I'm going more slowly than you... while I say you're going more slowly than me. I bolded the main wrong part, and strikethrough'd ... yuck. The character is only talking about delay of light and has neglected time dilation entirely, but explains it as if it's time dilation. In the striked part, the character is describing differential ageing or total time, and describing it as a differential rate of time (which is constant at a fixed relative velocity).
Strange Posted June 7, 2019 Posted June 7, 2019 4 minutes ago, md65536 said: No, Insignificance gets relativity wrong I don't think Einstein and Monroe ever met, either. 1
md65536 Posted June 7, 2019 Posted June 7, 2019 3 hours ago, mea1top said: wouldn't, on this basis, each observer conclude that the other observer had the same time reference - the only issue being the amount of time light takes to reach each one, which can be accounted for by each? What do you mean by time reference? In the situation described, with no one stopping, each observer would measure the other's clock ticking slower, in addition to seeing it tick much slower due to delay of light.
mea1top Posted June 7, 2019 Author Posted June 7, 2019 48 minutes ago, md65536 said: No, Insignificance gets relativity wrong. However the quote above was cut off right before it gets bad. https://www.springfieldspringfield.co.uk/movie_script.php?movie=insignificance I bolded the main wrong part, and strikethrough'd ... yuck. The character is only talking about delay of light and has neglected time dilation entirely, but explains it as if it's time dilation. In the striked part, the character is describing differential ageing or total time, and describing it as a differential rate of time (which is constant at a fixed relative velocity). yes, exactly - sorry if it wasn't clear I attached the whole quote since it was too long to include in the box - and this is exactly the bit that looked wrong to me. 42 minutes ago, md65536 said: What do you mean by time reference? In the situation described, with no one stopping, each observer would measure the other's clock ticking slower, in addition to seeing it tick much slower due to delay of light. yes, I agree - but the screenplay seems to suggest that the slowing clock is caused by the delay in light reaching the other person - which is surely wrong? Someone else has answered this below. thanks 48 minutes ago, Strange said: I don't think Einstein and Monroe ever met, either. yes, I think that's a given - it's a piece of fantasy - a what if? but no suggestion that that part is historically accurate 4 hours ago, mea1top said: Just curious - as a non-science major - the Nicholas Roeg film has a scene in which Marilyn Monroe explains special relativity to Einstein. But I have a feeling the explanation is wrong - please see script below - wouldn't, on this basis, each observer conclude that the other observer had the same time reference - the only issue being the amount of time light takes to reach each one, which can be accounted for by each? I've had to attach it as the script extract is too long otherwise. Thanks for your views! Script: Insignificance.docx Sorry - to avoid confusion there is an ATTACHMENT above called "insignificance" with the full quote in it - I had to attach that since the box wouldn't accommodate the full quote. 1 hour ago, md65536 said: What do you mean by time reference? In the situation described, with no one stopping, each observer would measure the other's clock ticking slower, in addition to seeing it tick much slower due to delay of light. actually, I think what I meant was this - if it was ONLY about the fact that there is a delay in the light reaching the other person, wouldn't that person just say to herself - oh well, it's taken light a minute to reach me, therefore in fact he has the same time as me, if I add on that minute? Does that make sense - or am I going up the wrong tree. I think I understand and agree with your other point - which I think is mine too - that time delay and time dilation have been CONFLATED and CONFUSED with each other - is that right?
Strange Posted June 7, 2019 Posted June 7, 2019 54 minutes ago, mea1top said: yes, I think that's a given - it's a piece of fantasy - a what if? but no suggestion that that part is historically accurate Although my comment was a bit of a joke, there is a serious point: how accurate do you expect a work of fiction to be? Ironically, we might hold this sort of drama to a higher standard of accuracy than an SF movie, where we expect the rules of physics to be violated for the benefit of the plot. But maybe I am taking your question too literally. Maybe you are just asking about relativity!
mea1top Posted June 8, 2019 Author Posted June 8, 2019 1 hour ago, Strange said: Although my comment was a bit of a joke, there is a serious point: how accurate do you expect a work of fiction to be? Ironically, we might hold this sort of drama to a higher standard of accuracy than an SF movie, where we expect the rules of physics to be violated for the benefit of the plot. But maybe I am taking your question too literally. Maybe you are just asking about relativity! actually that's a good question that I like - I have a personal interest - I have a novel about Newton with an agent at the moment - and one of my purposes was (as a non-scientist) to understand the basics well enough and to get that across accurately in the novel - and also just to express my wonder and excitement at the basic ideas and concepts that Newton was expressing. I was also interested just to know about relativity and whether this was accurate. But yes, I think you're right - with SF you can get away with more! (But yes, I'm disappointed with fiction that either doesn't even try to convey the science (and just focuses on the scientists' love life or what-have-you) or that actually gets it wrong! 1
md65536 Posted June 8, 2019 Posted June 8, 2019 2 hours ago, mea1top said: if it was ONLY about the fact that there is a delay in the light reaching the other person, wouldn't that person just say to herself - oh well, it's taken light a minute to reach me, therefore in fact he has the same time as me, if I add on that minute? Does that make sense - or am I going up the wrong tree. I think I understand and agree with your other point - which I think is mine too - that time delay and time dilation have been CONFLATED and CONFUSED with each other - is that right? Yes that makes sense. That's what happens at speeds low enough to neglect relativistic effects. https://en.wikipedia.org/wiki/Einstein_synchronisation Clock synchronization can be "achieved by "slowly" transporting a third clock from clock 1 to clock 2, in the limit of vanishing transport velocity." Then you'd say these clocks measure the same time. Worse than conflated and confused, time dilation was completely ignored, and relativity was presented over simplistically. They cared about getting Einstein's hair right; the science wasn't important. I think it's terrible, because a lot of people base their understanding of things on fiction, then go on to be a politician who decides NASA's budget or what to do about climate change etc., all the while perpetuating "the science wasn't important." (Rant cont.) Fictional science is probably fine, but writers throw in real concepts or jargon to be more interesting or sound legitimate or whatever. How many people could earnestly debate multi-world theories, without ever taking a physics course? Where do they get their information?
mea1top Posted June 8, 2019 Author Posted June 8, 2019 10 hours ago, md65536 said: Yes that makes sense. That's what happens at speeds low enough to neglect relativistic effects. https://en.wikipedia.org/wiki/Einstein_synchronisation Clock synchronization can be "achieved by "slowly" transporting a third clock from clock 1 to clock 2, in the limit of vanishing transport velocity." Then you'd say these clocks measure the same time. Worse than conflated and confused, time dilation was completely ignored, and relativity was presented over simplistically. They cared about getting Einstein's hair right; the science wasn't important. I think it's terrible, because a lot of people base their understanding of things on fiction, then go on to be a politician who decides NASA's budget or what to do about climate change etc., all the while perpetuating "the science wasn't important." (Rant cont.) Fictional science is probably fine, but writers throw in real concepts or jargon to be more interesting or sound legitimate or whatever. How many people could earnestly debate multi-world theories, without ever taking a physics course? Where do they get their information? Yes, agreed - I think fiction has a vital role in extending knowledge and interest of science - so it's incumbent on fictional creators a) to actually include it! and b) to get it right.
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