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Jan 26, 2020 23:31
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Grand Fromage posted:Oh my god. Read a book about special relativity, you may not like my attempt to make a simple example but you're seriously arguing with me that relativity isn't real. Take it up with physics. if there was a required reading to understand that your examples make sense despite appearing to be easily accounted for by logic then you should've said so. if you're actually right then you know it, who cares what we say, but you'll need to come up with better examples if the point is to make us understand.
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Jan 26, 2020 23:33
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adaz posted:A lot of the naive explanations are missing what happens when you throw motion into it which causes time to pass slower to the observer. In the asteroid example the relative motion isn't super high and its harder to show he's arriving before the event happens. I lightly edited the wikipedia to remove the heavy lorentz calcs and just leave the pretty simple pure maths What if we throw quantums into the situation and Bob and Alice receive messages instantly via quantum-entangled network? Not a physicist, genuine question
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Jan 26, 2020 23:37
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Grand Fromage posted:You've taken information from ten years in Earth's future light cone and brought it to present Earth. Swap the asteroid for a race. Go observe the outcome, bring it back before the signal reaches Earth, place a bet on the winner since you already know the outcome.
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Jan 26, 2020 23:37
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adaz posted:A lot of the naive explanations are missing what happens when you throw motion into it which causes time to pass slower to the observer. In the asteroid example the relative motion isn't super high and its harder to show he's arriving before the event happens. I lightly edited the wikipedia to remove the heavy lorentz calcs and just leave the pretty simple pure maths See that's a good explanation. Like you say most sci-fi side steps it by saying that FTL ships aren't actually travelling faster than light, but are taking shortcuts through space in one way or another mean they arrive before light but never technically travelled "faster" than it. In the presence of such a Star Trek or Star Wars style ftl drive (regardless of the probable impossibility of actually building one) it seems like causality remains intact, just with some cool visual artefacts.
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Jan 26, 2020 23:38
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I have read a book about special relativity but I haven't bothered to read any of this argument.
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Jan 26, 2020 23:40
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I think I'm going to go huff a paper bag full of mycelial spores until I understand time travel. 
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Jan 26, 2020 23:41
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Epicurius posted:I'm not a physicist, but I don't see how that's time being messed up so much as that there's normally a delay in getting information. We were talking before in the thread about spoilers, and I guess new episodes air in the rest of the world the day after they do in the US. So, if I watch the new episode and post, "We find out in this episode that the Picard show is just a holodeck simulation put on by Commander Riker to figure out what he should do about the Pegasus", and somebody reads that and is thereby spoiled, because he knows information before he could watch the episode, I haven't messed up his timeline. I've just been a jerk. in this scenario he wasn't breaking cause and effect and unfortunately building an easy way of showing cause and effect breaking is tough but consider: 1. Earth observes a distant star - say romulus - go supervnova 4 light years away. 2. Earth says oh poo poo! time to call in the Star Fixes and sends a message at 400x the speed of light to a spaceship traveling at very high values of c - say .99c. 3. On ship time it's 1 light year away from Romulus and 3 LY from earth when the message was sent by earth at 400x the speed of light. 4. Due to the effects of time dilation in the spaceships reference frame the star is still fine when it receives earths message. 5 The ship receives the message and immediately changes course and fixes the star Ta-da magic. We broke causality. In reality the distance sand speeds are wrong I'd need to do the lorentz calcs to make it right but more or less that's how it works. Senor Tron posted:See that's a good explanation. Like you say most sci-fi side steps it by saying that FTL ships aren't actually travelling faster than light, but are taking shortcuts through space in one way or another mean they arrive before light but never technically travelled "faster" than it. Well star trek would still have the same problem due to the fact that apparently messages can fly across the galaxy at arbitrarily high speeds leading to scenarios like the one I posted above. Starships to, if they were used to convey messages.
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Jan 26, 2020 23:41
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The sensor/security footage cloak seems dumb. Has there been a cloaking device like that in ST before? Also he never checks that for himself. As far as we know, his butlers could be in on it and are just lying about that.
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Jan 26, 2020 23:41
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Senor Tron posted:In the presence of such a Star Trek or Star Wars style ftl drive (regardless of the probable impossibility of actually building one) it seems like causality remains intact, just with some cool visual artefacts. I don't have the math on hand but it's demonstrable that any method of information propagation between two points which occurs faster than a direct path c from one to the other allows a similar backwards-transmission scenario to occur, the method of FTL or shortcut-FTL isn't particularly relevant. What adaz gave was a demonstration for that particular direct-FTL, but the proof has been generalised to show that kind of causality violation can occur regardless if information arrives at a point before a hypothetical direct-path c in a vacuum. MikeJF fucked around with this message at 23:47 on Jan 26, 2020 |
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Jan 26, 2020 23:41
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Yeah to be clear, Fromage, I get what you're saying in the sense that I understand your words. I'm not disputing either that this is how it would work in real life especially in the example of the two ships travelling at different directions so the space between them is growing faster than c. BUT, it seems implicit in a situation like Trek or the like that the existence of fairly accessible FTL technology resolves the problem, because it means (in effect) that information can travel faster than light, and that this information would be considered by observers to be more authoritative than that of lightspeed information. Come to think of this I think this is what the 'stardate' poo poo is supposed to be. adaz posted:in this scenario he wasn't breaking cause and effect and unfortunately building an easy way of showing cause and effect breaking is tough but consider: Nessus fucked around with this message at 23:45 on Jan 26, 2020 |
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Jan 26, 2020 23:41
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^^^ It depends on where the ship was at or maybe it used its tachyon beam to also send something at 400c that'd fix the star but yes! Where the ship is in space very much matters assuming at that point it all goes back to "normal" physics without accounting for FTL AntherUslessPoster posted:What if we throw quantums into the situation and Bob and Alice receive messages instantly via quantum-entangled network? Not a physicist, genuine question So far its not been proven that quantum entanglement can be used to send information. As long as that remains the case it doesn't matter. The effect appears to occur in both places at the exact same time but since the effect cant be used to send information there is no potential violation of causality. adaz fucked around with this message at 23:46 on Jan 26, 2020 |
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Jan 26, 2020 23:43
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adaz posted:in this scenario he wasn't breaking cause and effect and unfortunately building an easy way of showing cause and effect breaking is tough but consider: Erm. 1. if its 4 LY away it happened back in 2016, or I am wrong? adaz posted:So far its not been proven that quantum entanglement can be used to send information. As long as that remains the case it doesn't matter. The effect appears to occur in both places at the exact same time but since the effect cant be used to send information there is no potential violation of causality.
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Jan 26, 2020 23:48
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AntherUslessPoster posted:Erm. I think you're starting to get why this is a problem. It happened in 2016 _in our reference frame_. It's still early 2016 or late 2015 in the starships reference frame due to the effects of time dilation and the event hasn't occurred. Depending on their position they can head right towards the star and fix it without ever encountering anything. As far as quantum physics question I'd have to think about it. If you really could send things simultaneously across arbitrarily large distances even in different references frames at some point you're going to cause paradoxes which nature seems to not allow.
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Jan 26, 2020 23:52
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AntherUslessPoster posted:Erm.
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Jan 26, 2020 23:54
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I have chilled myself out. Sorry for being unchill.AntherUslessPoster posted:Erm. You are wrong. You're assuming an objective reference frame that all events take place in. This is how we think since that's how we experience the universe. Technically you and I aren't experiencing the same reference frame, but we're so close together that for all practical purposes we are. AntherUslessPoster posted:But what if? Then causality doesn't exist and physics as we know it is fundamentally wrong. It's possible that's the case--nobody thinks we have a complete understanding of physics--but it's hard to explain how we wouldn't have observed something so major. Grand Fromage fucked around with this message at 00:00 on Jan 27, 2020 |
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Jan 26, 2020 23:58
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I like Star Trek, guys.AntherUslessPoster posted:Thanks for the TOS input guys, I'll guess I will start my next week with To add to your watchlist, I've used "Day of the Dove" as a first episode and it worked well. It has Klingons, a space entity, and it's funny. The stakes aren't too bad, and the moral about getting along is at the heart of Star Trek. Being friends with Kang leads to victory, and Kang sees it too. Discovery would be so much better to me if they attempted to keep the look of the ships more in line with canon. The Klingon ships are just loving insane, and the Starfleet ships are mostly wonky. The Shenzou was okay, but that's about it for the new ships. The Enterprise is awesome though and a great update of the original design. MichiganCubbie fucked around with this message at 00:03 on Jan 27, 2020 |
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Jan 27, 2020 00:00
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I haven't gone much farther than university physics, but I never heard that an event doesn't happen until the light of it happening hits your eyes. As far as I know, relativity mostly just applies to how the the size of an object and the rate of time it experiences changes depending on how fast it goes. Do you have any articles or something that explains how things don't happen until the light of it happening reaches us?
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Jan 27, 2020 00:02
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Powered Descent posted:I think I'm going to go huff a paper bag full of mycelial spores until I understand time travel. is how it all starts. You huff a few bags and then you wake up on Alpha Centauri with a green chick with 7 breasts and 2 dicks wondering how you got there.
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Jan 27, 2020 00:07
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Grand Fromage posted:Then causality doesn't exist and we should decompress the Main Shuttlebay; the explosive force may push us out of the way. Fixed
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Jan 27, 2020 00:07
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Cojawfee posted:I haven't gone much farther than university physics, but I never heard that an event doesn't happen until the light of it happening hits your eyes. As far as I know, relativity mostly just applies to how the the size of an object and the rate of time it experiences changes depending on how fast it goes. Do you have any articles or something that explains how things don't happen until the light of it happening reaches us? When the event occurs is relative to the observer. It is impossible to describe the time an event occurs in absolute terms to anyone outside your reference frame - it's one of the keys of Einstein's special theory of relativity. The generic wikipedia article on it isnt bad for an overview. I dont have a good book recommendation unfortunately all of mine are now 20 years out of date college textbooks. adaz fucked around with this message at 00:20 on Jan 27, 2020 |
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Jan 27, 2020 00:13
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Cynic Jester posted:
You say this like it's a problem
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Jan 27, 2020 00:14
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I am not that well versed in physics, but isn't the whole idea of warp drive that it cheats relativity because you are warping space to go FTL? I know the show also says that they used 'subspace communication' to have instantaneous communication across space as well, although that is not something that is very well explained
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Jan 27, 2020 00:16
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Powered Descent posted:I think I'm going to go huff a paper bag full of mycelial spores until I understand time travel. Pleased to have you with us, Commander Stamets.
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Jan 27, 2020 00:18
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FlamingLiberal posted:I am not that well versed in physics, but isn't the whole idea of warp drive that it cheats relativity because you are warping space to go FTL? It doesn't matter _how_ it cheats it just the fact that it does. As long as any information can be transmitted at faster the light, doesn't really matter the mechanism, causality breaks down. If information couldn't be transmitted as seems to be the case with some real world things such as quantum entanglement than things can move faster than light without causing causality problems.
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Jan 27, 2020 00:18
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Grand Fromage posted:I have chilled myself out. Sorry for being unchill. Wouldnt that ship being 1LY from the supernova be first to observe supernova and then we at 4LY? I’ll go deeper into my simpleton mind before sleep and will propose adding a reference for all of that. We have three mechanical superclocks that show full earth date and time without error. One is here on Earth. One is at romulus, dinosaurs (voth lmao) sent it there on a subFTL ship ages ago and it is standard for romulus now so they have our GMT date and time. The third on is on ship from the post, 3LY away from us and 1LY from romulus. Romulan sun goes nova at 20.02.2020 2pm GMT (they transmit it everywhere that they went supernova). We see the sun go supernova 4 years later on 20.02.2024 2pm gmt and note it as such. What time will clock on ship show at the moment of supernova? Is it 20.02.2021 2pm on the clock? Erulisse fucked around with this message at 00:22 on Jan 27, 2020 |
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Jan 27, 2020 00:18
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FlamingLiberal posted:I am not that well versed in physics, but isn't the whole idea of warp drive that it cheats relativity because you are warping space to go FTL? e: Also the synch clocks would have gotten distorted in the course of being carried around, if I understand correctly. If the FTL radio is used to send out some kind of arbitrary but universal time stamp, does that help things?
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Jan 27, 2020 00:22
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Rhyming is the best way to make yourself understood so here goes: If you've never heard of Minkowski don't talk to me about relativity.
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Jan 27, 2020 00:24
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Anyway, never mind FTL and time travel, my favourite thing that makes no sense in Star Trek is how they can use the universal translator to pretend to be native speakers. Why doesn't their lip movement give them away?
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Jan 27, 2020 00:24
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marktheando posted:Anyway, never mind FTL and time travel, my favourite thing that makes no sense in Star Trek is how they can use the universal translator to pretend to be native speakers. Why doesn't their lip movement give them away? Because until DISCO and Beyond, the lip movements matched perfectly! 
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Jan 27, 2020 00:25
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AntherUslessPoster posted:Wouldnt that ship being 1LY from the supernova be first to observe supernova and then we at 4LY? This is a pretty important observation. The Romulan clock wouldn't read 20.02.2020 it'd read some other different value depending on the sub ftl speed the voths sent over. If they were going slow enough - say a moving car - it'd be nanoseconds off. If they went fast enough it'd be days or years off from our clock. As soon as the clocks were synchronized and started moving they _all will read different times_. This is a real world thing and it has to be accounted for - for example - with GPS satellites or the distances on your phone would be off by quite a bit. The exact times the clocks measure depends on special relativity and the speed of the ship. It'd be some value before 20.02.2020 though in this example. marktheando posted:Anyway, never mind FTL and time travel, my favourite thing that makes no sense in Star Trek is how they can use the universal translator to pretend to be native speakers. Why doesn't their lip movement give them away? Also how does it now when cursing to not just say the curse word??
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Jan 27, 2020 00:26
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Arglebargle III posted:Rhyming is the best way to make yourself understood so here goes: The Lost character who gets all hosed up from time shenanigans?
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Jan 27, 2020 00:26
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Arglebargle III posted:Rhyming is the best way to make yourself understood so here goes:
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Jan 27, 2020 00:31
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Im feeling superdumb but cant loving sleep now. Romulus goes supernova at some time. Like 1billion seconds from universe creation. Lets just call it that. We observe it at 1b seconds plus delay. We instantly relay that to ship and they FTL there. Their ship time is nova minus delay. They arrive at nova at 999million seconds. THEIR SHIP time shows that time but the nova happened, they are ‘delay’ younger than universe but that would not change the fact that nova happened, right? God why did I started being interested in physics while Im a grown up adult and not back in school. I got poo poo to do tomorrow!
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Jan 27, 2020 00:46
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AntherUslessPoster posted:Im feeling superdumb but cant loving sleep now. So the uh Nova hasn't happened yet to the ship in their reference frame of 999million when they arrive the star is still there shining brightly even though in Earths reference frame its been dead for X seconds. Again for this to really work the ship would need to be in motion and likely at some relatively high value of the speed of light . But this exact scenario is why - as we currently understand physics - it appears FTL is impossible. There aren't many ways the universe or events could happen as we understand it to allow for it if it ever existed and if any $entity discovered it. If you want a somewhat fun - and the only one I know of that lives in this world - sci fi series that takes these implications into account Charles Stross Singularity Sky & Iron Sunrise are pretty good yarns! adaz fucked around with this message at 00:55 on Jan 27, 2020 |
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Jan 27, 2020 00:52
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AntherUslessPoster posted:Im feeling superdumb but cant loving sleep now. As best as we can tell, in reality, FTL communication is impossible.
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Jan 27, 2020 00:54
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adaz posted:It's a minor quibble but dont forget that almost every single sci-fi thing (outside of Charles Stross) ignores the fact that if FTL travel/signals are possible then causality breaks down (i.e. time travel is possible) see tachyonic antitelephone and relativity of simultaneity for more. I would deeply love for someone to explore this in tv or film but it sort of breaks human understanding to view time and events like this. "The Forever War" covers this in an interesting way. The whole story follows these elite soldiers training to fight this new alien threat called the Taurens. The humans have some tech to allow them to travel near the speed of light, but it has heavy relativistic effects. So like, they fly out to get into their first battle with the Taurens, totally massacring them there. Then they go somewhere else to fight, but because of time dilation, when they get there the Taurens have way more advanced weaponry since they've had so many more years to advance compared to the ship. Then they return home, and their whole expedition was like 2 years from the soldiers' perspective, but it's been like 30 years because of time dilation. They get home and find a world where poo poo has changed massively, governments encourage everyone to get into homosexuality, everybody loving hates vets and anyone in the military, widespread unemployment and out of control gun violence, etc. They get future shock a few times after these time-dilation trips, book examines changes in society over time an d their reception towards these old soldiers. Eventually the main character goes through like another 4 years of military service doing more near-lightspeed travel and becomes the oldest living soldier, centuries old. In the end humanity starts getting into some transhumanism and cloning and everyone is a clone simply called Man and they can know understand Tauren. Turns outs the Tauren were all clones too and we get along great, back in the day some colony ships dissappeared due to accidents, and war-hawks back on Earth used it as an excuse to start a meaningless conflict that lasted a thousand years. Oh yeah, and the new fully clonomatic gay space clone communists establish heterosexuality-allowed colonies of old-style humans just in case their clone-evolution thing doesn't pan out. the main character can't fit in so good in the new world so he retires to one of those colonies and he finds his old army gf(she purposely took advantage of time dilation to age slower hoping they would meet up again) and they live happily ever after.
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Jan 27, 2020 00:55
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I’m sorry, but why would the government be encouraging people to just do gay sex
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Jan 27, 2020 01:00
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The forever war owns and the tldr is because of overpopulation
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Jan 27, 2020 01:00
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FlamingLiberal posted:I am not that well versed in physics, but isn't the whole idea of warp drive that it cheats relativity because you are warping space to go FTL? From what I understand of the made up science of it, if the universe is a sphere, subspace is like a smaller sphere within that first sphere. So if you send a signal through subspace, it doesn't have to travel as far as it would through normal space, so it gets there faster or whatever.
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Jan 27, 2020 01:01
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