“Scotty ta’ bridge! Im givin’ her all I can Cap’n She’s on warp nine now! If I push her any more, she’s gonna blow the phase converters and I’ll have to change the dilithium crystals!”
Yup. Even back then they coined their propulsion method warp, implying that a warping or bending of space time occurs. The enterprise never exceeds the speed of light or gets even close to it (I think typically full Impulse speed, essentially a fancy rocket propulsion) gets you to 0.25%. What happens instead, even though they never spelled it out in TOS, is the engine somehow contracts the space in front of the ship reducing the distance to a hop and a skip. There are a couple of instances in the franchise’s literature corner where ships had to go relativistic because warp wasn’t working for whatever reason, and they accelerate the ship with Impulse to .9c. As a result they were able to cross vast distances in the range of light years within a few months of their own time perception.m, but skipped a century from any outside observers.
Okay, so a physicist here (well, at least by education, and relativity was always the part of physics that interested me the most). 8:50 Basically, the relativistic mass changes by the same factor by which time is dilated, which is 1/sqrt(1 - v²/c²), so if time slows down twice, mass increases twice. Although the relativistic mass itself is a bit of a controversial thing - it is being taught as a consequence of special relativity, and relativity does imply changes in inertia as objects accelerate, but physicists in academia tend to treat the rest mass as "the mass", and ignore relativistic mass as a notion, for multiple reasons which I won't list here, because a RUclips comment isn't the best place to do so. 9:54 The velocity would be (0.9+0.9)/(1+0.9*0.9) = 1.8/1.81 = 0.994 c, so you got it right 😉 11:48 As for exceeding the speed of light - while you're right that within special relativity it's impossible for a massive object to reach the speed of light or exceed it, it does make some limited sense to consider frames of reference exceeding the speed of light. So for a thought experiment, we can imagine the rocket and people on it being converted to tachyons and going faster, and the math of special relativity still works... at least to some extent. 12:34 The thing with cause and effect is a bit more complex. The thing is, some cause and effect relationships would be reversed, and some wouldn't. This is because whether you're travelling forwards or backwards in time starts to... depend on the observer. If you imagine multiple "normal" observers obeying the c speed limit, depending on their relative speeds, some would see you going in one direction and forwards in time, and some would see you going the opposite direction and time in your rocket flowing backwards. And some would see you as a weird object moving at an infinite velocity that just materializes for one instant and disappears the next. Again, it's a bit hard to explain how this is possible in a comment, unfortunately, so I'll have to leave it at that for now 😅 13:13 Again, that depends on the observer. To _some_ observers, you _would_ be travelling backwards in time. But to others, you wouldn't be. And these observers would all be moving forwards in time relative to each other. It might sound kind of self contradictory, but I assure you that it isn't! 😅 14:25 Yup, that's a big problem. At fast enough speeds, regular light from stars would be blueshifted so much that it would become harmful. Also, the intensity of the light you're receiving from the front grows as you accelerate, so it gets blueshifted _and brighter,_ further exacerbating the problem. Anyway, don't take the above points as criticism. I still think your video is very good, and the video you're addressing mixes truth with fantasy in an awful way, so it's great that you're pointing it out. Definitely a thumbs up from me 👍 (for you, not the other guy(s) 😁)
I'm no physicist, but I know a decent bit about length contraction near the speed of light, and I know the lengths of items approach zero as you get closer to the speed of light, so wouldn't going ftl flip your rocket in the opposite direction?
@@Stingpie That's an interesting question. I guess that can depend on how exactly you're going to accelerate past the speed of light, because you can't really do this continuously starting from a sub-light speed. It does seem, though, that expecting the rocket to get flipped backwards makes some sense. Then there is the problem that the direction along the rocket for you would be a timelike direction in the frame of the rocket, so that also complicates things a bit.
I always wondered if, since the length contraction seemed to only be in the direction of travel with none on the other two dimensions of space, is it sort of like you're trading off a space dimension for another one at 90° to it? I picture the two dimensions like the _x_ and _y_ axis on a grid, with a plot approaching zero in one coordinate while asymptotically approaching infinity for the other, and vice versa when the two are swapped. It so easy to diagram what I mean, hard to concisely put it into words.
@@bobblum5973 "is it sort of like you're trading off a space dimension for another one at 90° to it?" Kind of, but not quite. Lorentz transformation - which is the basis behind relativity - is very similar to rotations in some aspects. So when an observer travels in the x direction relative to another observer, it's a bit as if his spacetime coordinates were rotated in the x-t plane relative to the other observer's coordinates. And then time dilation and length contraction are kind of similar to foreshortening - for example if you measure some time interval, it's kind of like a line segment along your t axis, and since it's rotated relative to the other observer's t axis, its length along the other observer's axis is slightly different. But it's not _quite_ rotation. If it was, time dilation and length contraction would be the other way round, that is: time would flow faster for moving observers, and moving objects would appear longer. You can imagine rotations as going in circles around a point - Lorentz transformations are then like going in _hyperbolas._ And where trigonometric functions are used to describe rotations in equations, they get replaced by hyperbolic functions in Lorentz transformations. This would also be easier to see on a diagram, but I won't risk this comment disappearing by posting a link 😅
Saying this as someone who used to have this misconception: Another danger with sites like that is that when they get science wrong and scientist correct them, to the layperson I can look like science doesn't know what they think. Which created the opening for ever scientific conspiracy theory from flat eart to YEC to antivax
Well, lucky for us all than that Theism and atheism are so big that they spawned many YT-Channel diving into it without Bias: The Atheist-Channel. Some polite, some funny, some serious, some goofy: Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale and Atheist Jr. All worth cheking out.
Yeah, a lot of people expect science to be ... well an exact science and have all the answers. When in fact science is made up of a series of theories with a basis and evidence, and everyone is constantly trying to prove eachother wrong. There is no 'big science' somewhere deciding what we all study and think. There's just the general consensus of which theory has the most credibility.
Ridddle gives the aura of a trustworthy source of science data, but their videos are always absolutely chocked full of data. It’s actually pretty fun to watch them and see how many mistakes you can count- just don’t make a drinking game out of it, you’d end up having to get your stomach pumped.
There is a short sci-fi movie, that perfectly explains this "travel back in time". In it humanity sends a ship to travel faster than light, and so far away, that when he looks back at Earth (which in his time (year 2XXX) is reddish, dust covered desert), he sees her as the planet we have today - covered in oceans and forests. He didn't travel back, he just traveled further, than the light from his time.
Only problem is, he outran that light He would have to wait---years? centuries? Millennia? Depending on how fast he was going (assuming that was even possible...which as far as we know it isn't). Light from the past would catch up first, but he would still probably have to wait a long time.
@@jayfredrickson8632 He outran the light from his time, and was seeing light from 100 years ago or so. Unless he traveled more than 4,5 billion light years, he would see the Earth.
Another nitpick: Even if you're looking directly backwards, at 10% of the speed of light, the stars would not appear red. They might look a little more yellowish-white than usual, but that's about it. Because _all_ light is frequency shifted, that also means that the UV light the stars are emitting also gets shifted to become blue light as well, so you still end up seeing a full range of visible light (white light) from the star, there's just less UV light (and more infra-red), and the peak emission wavelength shifts a bit (so it might change its tint a little bit more yellowish). You'd actually need to get to somewhere around 50% of the speed of light before things would really start looking visually red (behind you), because that's around the point that the UV/blue emissions actually drop off enough that the majority of the visual light you see would appear to be in the red end of the spectrum.
I was waiting for someone to point this out because we actually detect Doppler shift through comparison of frequencies (there literally isn't any visible color difference, at least to any measurable degree, in the (albeit slower) stars we see)
Red shft and blue shift is kind of misunderstood. Some think that all you move away from, turns red. That's NT te case. The color spectrum turns TOWARDS red. For example, at slower speeds, something that is blue turns teal, then green at higher soeed, then yellow etc. And it's not single colors. It's a spectrum of colors, depending of the composition of the material or rather matter.
Some polite, some funny, some serious, some goofy: Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale and Atheist Jr. All worth cheking out.
@@nenmaster5218 I agree, yeah, and would add AronRa and Viced Rhino to that group (even Gutsick Gibbon!), but this really looks like it belongs on another comment.
The formula for adding velocities is (u+v)/(1 + uv/c²), so adding u=v=0.9 does give 0.994+. A popular treatment of relativity I read as a lad stated that there's no way to know what would happen to a ship that went faster than light, and simply said that such a craft could travel to Oz for all we know. That was definitely more accurate than this muddle.
I mean we have the theory of relativity that tells us what happens. The theory would allow for tachyons to exist. A Tachyon is a particle that will always move faster than the speed of light. If you add energy to a tachyon it will slow down and if you add an infinite energy to it, you could slow a tachyon down to the speed of line. If a tachyon losses energy it would speed up. Also Tachyons would always travel backwards in time and would have a negative mass. Obviously those are only a mathematical solution to the theory of relativity and there is no proof those particles actually exist. But this does suggest that a rocket above the speed of light would behave similar to tachyons although there is no mathematical solution to movement faster than the speed of light with a positive mass if I'm not mistaken.
@@Taktikameise Tachyons wouldn't have a negative mass, but rather an imaginary mass. Also, what is faster than light for one observer is backwards in time for another. As another poster has mentioned, if we have both relativity and FTL, then we lose causality.
@@tomkerruish2982 Yes my bad When I read about it the square of the mass was mentioned, not the actual mass and if that one is negative the mass has to be imaginary. Also it is unlikely they exist. Because they would be able to create your basic timetravel paradox. Like what happens if you message yourself with Tachyons to not message yourself with tachyons. Theory of relativity has other interesting mathematical solutions like White Holes, but to be fair the theories around them are a bit too high for me.
If Einsteins GR math is valid AND something could break the speed of light a spaceship could traverse certain paths through spacetime that lead back in time. But all the paradoxical things that are associated with these ideas/stories are just hints that our mathematical description of reality stopped working. Reality has no paradoxes, our (limited) understanding of reality creates them. "Causality, Relativity, Faster than Light travel... choose two of three."
@@RichWoods23 I think what the OP was indicating is that a universe could only have 2. If you take relativity and FTL, causality could not be Kemptville by the implication of VTL and relativity. If you take FTL and Causality, relativity would have to be thrown out. Our universe has Causality and Relativity, FTL isn’t an option because of that.
@@RichWoods23 FTL is technically possible under general relativity through stuff like wormholes right? It's just that when you combine FTL with time dilation under relativity it allows for time travel, breaking causality.
That video went wrong pretty early, but the bit about the astronauts own watch slowing down was particularly egregious. They really don't understand any of this, do they? They read another popular science article and failed to get any of it, then thought, "hey, let's make a video about it, it'll look cool"
For me, the best explanation of relativity is from the movie Deep Blue Sea. "Grab hold of a hot pan, second can seem like an hour. Put your hands on a hot woman, an hour can seem like a second. It's all relative."
@@stephenlitten1789 Yeah, I was told as a kid that Einstein had something something to the affect of "put your hand on a hot furnace and a second feels like an hour. Put your hand on a hot woman and an hour feels like a second". Whether Einstein was the one who originally said that or not, Deep Blue Sea didn't invent it :P
I appreciate the humor (and forgive me if this was meant purely as a joke/sarcastically), but this is obviously one of the worst possible ways to explain relativity (because it's extremely misleading), or I guess more properly, it's just not an explanation of relativity. It has absolutely nothing to do with general or special relativity, doesn't really describe frames of reference, and most especially, it's a misleading description of a phenomenon totally unrelated to relativistic time dilation, which might cause the listener to misinterpret what time dilation even is.
@@ByzantineDarkwraith Right on all fronts. Unfortunately, I'm unaware of any short and pithy explanation of relativistic time dilation. I do remember seeing a video many years ago (BBC, maybe) that explained it in a few minutes. There are a few on RUclips which may be what you are after.
"Unless of course you have the time stone...but that has been destroyed." Take my like for this casually random reference before I even finished watching.
The part where you mention its impossible to go F.T.L reminds me of a line from a filk song where someone goes the speed of light and then all of his family, friends and future generations die "You know someday your gonna win that race and fly back the years to your starting space"
Riddle's video should be classified as fantasy. To be Sci-Fi I'd prefer to see some attempt at believability. To be popular science I'd like some explanations rather than just jumping to wild claims. E E Doc Smith he isn't.
Some polite, some funny, some serious, some goofy: Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale and Atheist Jr. All worth cheking out.
Ridddle is one of those catchy headline channels that is providing videos riddled (pun intended) with plenty of misinformation and half-assed "facts". It should be taken with more than just a grain of salt.
If Planarwalk said "math" I wouldn't be able to watch this because an infuriating OCD aspect I have, is to say out loud "maths" to correct it. it's maddening!
What I find kind of strange is that we've abandoned the idea of a 'universal clock' because of general relativity, but if you think about it there still is a sort of standard clock, which started at the big bang, but then different areas of spacetime tick at different speeds. Framed like this, you can never go back in time but you can travel forward at different speeds.
it isn't that different areas tick at different speeds (excluding gravitational time dilation here since we are talking about cosmology), it is that observers moving at different velocities perceive different time speeds *for the other observers* (a observer is always at rest in their co-moving frame of reference). the age of the universe is given in the frame at rest relative to the galactic fluid (i.e. the sum total of the galaxies is at rest, even if individual ones still have some peculiar motion). combining that system with the assumptions of isotropy & homogeneity leads to the FLRW-metric, and the Einstein field equations simlify to only two equations, the friedmann equations, which are used to derive the age of the universe. If you are now moving with a velocity relative to the galactic rest frame, the time in the galactic rest frame appears to move slower, meaning for you the universe appears older.
@@freyja5800 You seem very well educated on this, so perhaps you could clear up a bit of confusion I'm having. I was wondering why, when someone is travelling in a rocket at 50% of light speed or whatever relative to the Earth, time in that reference frame moves slower, rather than the other way around. The reason this confuses me is because I've heard that there is no such thing as "absolute motion," and all motion is relative. Therefore, isn't the fact that, in the rocket's frame of reference, the Earth is travelling relative to it at 50% of light speed, just as valid as the fact that the rocket's moving at that speed in the Earth's frame of reference. Since either of them is moving at 50% of light speed relative to the other, and which one's moving just depends on which frame of reference you're looking at, why is it that time dilates in one of those specific reference frames, and it's not the other way around? Basically, how does the universe "choose" (I know it's obviously not an actual conscious choice) which reference frame experiences time dilation relative to the other, when they could both be considered to be moving at 50% light speed (depending on the reference frame chosen)?
@@ByzantineDarkwraith the source of your confusion is miscommunication. you are absolutely right, there is no preferred reference frame, and while for people on earth the time in the rocket seems to slow down, for the people in the rocket time on earth seems to slow down. combining this with the length contraction results in the conclusion that simultaneity of events is frame dependent (i.e. 2 things happening simultaneously in one frame might happen at different times in another reference frame). If you want to know more about that I would recommend looking into minkowski diagrams (spacetime diagrams for special relativity), and how you represent different reference frames in them. As for the rocket, the coordinate time is not a lorentz scalar, meaning it is not invariant under coordinate transformations. for that you have to look at the proper time, which is independent (and related to the spacetime trajectory of a given thing). proper time also explains why if the rocket where to turn around at some point, there would be an actual difference that is frame independent, and the difference is essentially caused by the acceleration needed to turn around. (I should note however that I mostly deal with simulations etc, and I haven't really dealt with relativity for a few years, so it might be inaccurate on the finer details)
@@freyja5800 I am no where near being called a physicist or scientist, but in the example above, wouldn't time on earth appear to be going faster for the observer on the rocket? Not slower? Another question I have. I understand that science has discovered that the universe is expanding in some places faster than the speed of light. With this being the case, couldn't theoretical FTL travel be possible "frame shifting"? In other words, could we shift our occupied frame using conventional acceleration, but shrink or expand space around our frame?
@@seanwolfe5161 sorry for the late answer for the questions: 1: no, as byzantine pointed out, there is no preferred frame in the universe, so the effects have to be symmetric in that sense (i.e. the moving thing experiences slower time, no matter which (earth or rocket) is moving & stationary)). Yes, that is kind of counterintuitive, but that is why I recommended minkowski diagrams, b/c they can help illustrate it. basically, in a 1+1D version (1 space, 1 time), in any given frame, the time and space axis are vertical & horizontal for itself, with lines of simultaneity being parallel to the space axis. when marking the time and space axis of another reference frame moving at a velocity & with a shared origin (i.e. a pure lorentz boost), both the time and the space axis of that frame as viewed from the current frame are angled towards the line of lightspeed (light is at a 45° degree angle), and the lines of simultaneity are also parallel to the space axis of that frame. this means that events that are simultaneous in that frame are not in your own, and if you draw the simultaneity line for a given T, for your T the corresponding time is the time on the slanted time axis at the same hight (on a line of simultaneity) and is smaller than T, but if you take the time T of the moving frame, and draw *their* line of simultaneity, due to the slant of their space axis it intersects your time axis below T, meaning for them, your time moves slower. as for the second question: the expanding faster than c is a direct consequence of the fact that the expansion rate is uniform everywhere, and it usually is given in km/s/mpc (kilometres per second per megaparsec, current vallue ~70km/s/mpc), if you have a distance far enough away, it will be faster than the speed of light. this isn't really something that can be controlled, since it is a cosmological phenomenon, and thus only applies on scales beyond galaxies, and cannot be influenced anyways. but the idea of using expanding/contracting spacetime to achieve FTL is indeed allowed by einsteins formulas, with probably the first version of a metric based on that given by Miguel Alcubierre (called the Alcubierre metric after him), but it requires exotic matter to work sadly, so probably will never be possible outside of science fiction.
I hate videos like the one you featured. It's like they tried to dumb it down and then the concepts got mistranslated in the process making them inaccurate and in some cases just plain wrong. Good on you on calling this one out. I agree with your critisisms and corrections.
Top 20 aint bad, I was at work when it came out. I enjoy the space themed videos you've done recently, I love it. May I suggest looking at sciences of going to Mars and videos about all that? Cause there's lots of issues with going to any planet that videos like these gloss over
Ah yes, Ridddle! I used to subscribe to them, until one video (not this one) was just too full of errors, and I had to drop that channel. It’s a shame to see that some things don’t change. In case you’re wondering, you’re spot on about the time dilation calculation. To have time move at exactly half the rate that it’s observed for a stationary object, the spacecraft would need to travel at square root(3/4) of the speed of light, approximately 86.6%. Ridddle - close enough if you forget things easily, but wrong enough if you have any memory at all. BTW, here’s an actually good video about why traveling near the speed of light would suck, from Cool Worlds: m.ruclips.net/video/b_TkFhj9mgk/видео.html One interesting factoid (at about 14:45 in the video): As you travel ever faster, the Cosmic Microwave Background radiation will blue-shift into visible wavelengths, then into even higher, more unpleasant intensities. Ouch!
My 5 year old watches terrible RUclips videos where they posit a “what if” and explain what would happen if that what if we’re true. Like, “what if the earth split in 2”. They then proceed to make up nonsense that would definitely not happen. I say all that to say, this video reminds me of those videos
if a rocket blasts away from earth at the speed of light, then according to their reference frame, it would be the earth that moved away from them at the speed of light, and therefore, everyone on earth would experience the same time shifted magical temporalportation of reversity.
It sounds like a take on the Star Trek Voyager episode where they go to Warp 10 and time stops making sense to Tom Paris as he devolves/evolves faster.
The most painful part for me was as soon as they said that the clock on the wall of the spaceship would start to slow down as seen by the passenger on the spaceship.... I couldn't help but pause the video and exclaim out loud to myself "no no no no no!", because it became apparent (well more apparent) that they didn't have even a basic understanding of what they were portending to educate people on. I then resumed the video and cringed the whole time (well except at Planarwalk's content). Now if they had specified that the clock on the wall of the spaceship would appear to slow down as viewed by a (relatively) stationary observer looking in a window of the spaceship as it flew by (ignoring the fact that they would never be able to see anything with it moving that fast, but regardless demonstrating the relative change in the flow of time), then that would be correct. Or say that the person on the spaceship, looking out the window at a clock tower as they flew by (again ignoring the problem of perceiving it at that speed), they would see it ticking faster than normal.
Even waaaaaaay before you got to the speed of light, the CMB would blueshift to billions of degrees Kelvin, so you would turn into vapour far before you even got there.
a couple corrections to your understanding: 3:00: this is actually not true, the light reaching you is not the same, you get one second worth of light every second. This is because even though you are moving, the light from the clock is still moving at the speed of light. The cause of the slowing down is time dilation, causing the emitted light to be always very similar because changes in the clock are very slow from your perspective. And this also applies when approaching the clock, this is intuitively not obvious but still true, think of the decay of muons from cosmic radiation, they go straight towards you but still their lifetime is longer than would be expected. Your arguments are the first part of the cause of blue/redshift seen by you (the second part comes from time dilation, in acoustics there are different formulas for the doppler shift because of a moving observer or a moving source, with light shifts these gets combined non trivially which incidentally means the shift in frequency of light is not quite symmetric when approaching or receding from a lightsource). Going "at" the speed of light doesn't change this, it's just the limiting case. 10:00: you are right the formula for addition of two percentages of the speed of light va and vb resulting in vt is vt=(va+vb)/(1+va*vb) so in this case would be (0.9+0.9)/(1+0.9*0.9)=0.9945
There's also the pesky thing with carrier particles, which move at the speed of light. You want all your atoms moving less than the speed of light if you want to keep your atoms together.
There are ways to tiptoe around the energy requirement to accelerate spaceship to the speed of light, or at least very close to it. It's a one-way trip but we've observed the particles near the event horizon of black holes exceed 99% of light speed.
Good news about the space debris: once you achieve a certain relative velocity, we're not sure exactly what but somewhere just shy of light speed, all the dust and micrometeors will interact with your spaceship as if they were gamma rays - and the ship will interact like gamma rays to the dust. So, collisions become a non-issue... after you've accelerated past the point where they're a very big issue, because of the mass amplification effect making every bit of dust equivalent to slamming your ship into a planet. But if you do get past that point, yeah, radiation shielding and you're good to fly. You should really have that rad proofing anyway, since even at much lower speeds, the blueshifting of normal starlight ahead will turn it very extra deadly. But, details!
If you look out of the side windows of the space ship you will indeed see the stars red shifted. It's called the transverse Doppler shift. The equation for Doppler shift when looking in any direction is complicated and is seldom mentioned in books, unfortunately.
Causality would only be reversed for someone inside the ship from the point of view of someone outside the ship. If you went faster than the speed of light you would appear to be going backwards -- that makes no sense, which is because it's impossible. Impossible things often don't make sense.
Have you not heard of the infinite improbably drive ? Personally I blame the Vogons and there poetry . Remember boys and girls never travel without a towel
12:35 The reverse of causality would not be "just in the rocket", because... its all relative :P For the people in the rocket, the rest of the universe is moving faster than light, so yeah, the universe would go backwards for them.
Some polite, some funny, some serious, some goofy: Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale and Atheist Jr. All worth cheking out.
the thing about time dilation fromula is that not only it's (1 - v^2/c^2), but a square root of that... This makes the time when traveling faster than speed of light not negative, but imaginary... (this is obviously wrong for many reasons, but I find it fun).
No complaints. Technically Eisenstein’s equation do have solutions to velocities greater than the speed of light but in out Universe that is unlikely to happen except in very unusual circumstances. Orbiting a rapidly spinning black hole for example could potentially create acceleration vectors that might make this possible but it’s all theory and had nothing to do with the video which you were reviewing. Great work btw, love your videos!!
Ahoy hoy, Planarwalk, I watched this video thinking I was going to be confused and not completely understand what you were saying! And the clips that you showed of their videos made me completely understand what you were saying! I actually said, "No", after you showed their clips & before you made any comments! Which makes me really happy! Because I do enjoy your videos and I honestly think you are very, very intelligent! Thanks for your videos and keep up the good work!! Oh and something to do a video on, Creaky just released an awesome video on this melted guy, check it out, and maybe do a video too. Even if you don't do a video on this melted guy, I think you'll enjoy Creaky's video!! 👍🏼
about 2:50 - the observed clock would actually be stopped, no matter if you go towards or away from it. this effect does NOT take light movement into account - this operates on space-time slices. the light reaching your eye effects apply on top of that a note about 7:49 - it's not that time dilation applies to the whole ship, it's the opposite - time dilation applies to the whole rest of the universe, but you ship. the point is that for you - your reference frame is just as normal as any other observer's reference frame. and it is this notion that you observe relativistic effects being applied to everything else, but another observer sees relativistic effects being applied to you - this is what causes so much misunderstanding and seeming paradoxes (not real ones, just caused by misunderstanding) and again for 12:43 - as far as you can see inside the rocket - the rocket stays still, and the whole universe moves "faster than light" around it. And that's the point of SR - no reference frame is "better" or "more correct", there is no "main" reference frame just a note on 10:04 - TECHNICALLY, specifically SR does not say that things cannot go faster - so technically math continues to work. it just the jump from subluminal to superluminal speed is what requires infinite energy and therefore seems impossible. so for all we know - there MAY be a whole set of superluminal particles living their own life (like tachyons), but they can never slow down to subluminal speeds. but that all is just what can be derived from math model, we have not actually observed such particles, nor we actually have idea how to (as far as i know) 13:48 - note, here we just operate with math equations, and speculate. here the the rocket ofc won't return, but the moment of rocket being still on earth will be "in the same now" with you - so it will be in the same timeslice with the flying rocket.... i know, this is indeed hard to have intuition about.
Yeah I saw that video, and I was very infuriated xd. Somewhere in that comment section must still be a long passionate piece of all the misconceptions I found xd
Just saw a video today about how long it would take to travel to each planet, and one of the first things it says is, it took 6 days for Apollo to reach the Moon from Earth. I did a double take like, what the whaaaat?
There was a young lady named Bright Who travelled much faster than light; She set out one day In a relative way And returned on the previous night. [Edit: I don't know the source.]
I think the timestone is the most scientifically accurate issue here. You can only use it to change the flow of time, but it's been destroyed. All facts no cap.
The Time Variance Authority has plenty of spare timestones. You just need to attract their attention somehow, then escape and grab one. Problem solved.
Sometimes , I think people watch too many movies , and that would be o.k. ( I watch too many movies ) but then they go on to mix up their movie ideas with their science and that is not o.k. Science fiction is not the same as science .
12:11 It's like asking: What would happen if 1 + 2 = 5 More information than this is required to answer, because our current universe can't account for this. There's probably some abstract algebra you can invent to allow this. But these new rules need to be declared to answer any hypotheticals. And even then, the hypothetical only applies to the fictional abstraction you just invented.
I think the same person voice overing ridddle is the same person in arnold ones and the same person is also in the scp foundation ones 😂 it's always nice to watch these kind of videos. None the less, most of the things are rather entertaining to watch I myself being a physics student, without prove and proper visualisation I don't believe anything and these things aren't experiments which can be observed rather contradictions based on what we've seen and gain knowledge so far
In logic we have an entailment that says anything follows from a false premise. So I can say "If the Earth is flat, all humans have green skin", and it's a correct entailment. That is, since the premise is false, I can make the conclusion. This of course also goes all humans do not have green skin, so we arrive back at false, namely the Earth is flat. - So "if we travel faster than the speed of light" - well any conclusion they make after that premise is a correct logical entailment
i really like ridddle but im supper happy to see someone debunk his video.... i dont always agree with what i see on his videos, i had a feeling he was getting some things wrong... thx dude... have you seen his flat earth video yet.....
One other Issue with the Micrometeorites peppering the Shuttle going at light Speed, the Atoms of the Meteorites and your Shuttle don't have the Time to move out of the Way or deflect each other like you would normally see and expect, so they would fuse together. This nuclear Fusion would not be a good Thing for you.
"You can't go at the speed of light (in vacuum)" is a bit simplistic of a statement. Yes, your local velocity will always be less than c. However, that doesn't mean you can't travel eg. from Earth to Alpha Centauri in less than 4 years, _from your own perspective._ It's impossible for you to travel there in less than 4 years from the perspective of observers on Earth (or on Alpha Centauri, for that matter), but _from your own perspective_ it is perfectly possible for you to travel that distance in less than 4 years (of your own time). There's no limit to how short your travel time can be. And yes, this even though your local speed never reaches c. (The solution to this seeming paradox is that, from your perspective, space contracts in the direction of travel, making the distance to travel, from your perspective, shorter. In fact, from a photon's own perspective travel time is always 0, and the entire universe has been contracted into a zero-width plane in the direction of travel.) And yes, that means that if you then return to Earth, more time will have passed on Earth than for you. Over 8 years could have passed on earth, while for you only 1 year has passed. Or a week. Or a day. (Of course in practice you wouldn't survive the acceleration needed for this, but theoretically.) So it would be more accurate to say that an external observer will never see you travel faster than c, nor will you ever measure your local speed as faster than c. Well, kind of. General Relativity throws some spanners in the works there too. While local traveling speed cannot exceed c, from any perspective, the _distance_ between two objects can grow faster than c, even from an external perspective. GR doesn't forbid this (and it's the reason why the entire universe is larger than the observable universe. Most galaxies that exist in this universe are receding from us faster than c. And no, that doesn't contradict GR. On the contrary, GR predicts it.)
imagine you're running through a moving train carriage. to you, you're just running. to someone on the platform looking at you through the window, you are going 100mph... that's relativity kids. (thanks anthony burgess, who, spent more time on the analogy)
I think the funniest part is when the clock ***in the same room*** with the passenger slows down. If anyone wants to know what physicists would actually think would happen if you went faster than the speed of light, you should look up the hypothetical particle tachyon.
I am sure someone else has said this but… you can travel faster than the speed of light using an Alcubierre warp drive. That is because the ship itself isn’t really moving. Space time has no speed limit as demonstrated by the expansion of the universe.
For those (still) interested, there is an excellent video about light and time: ruclips.net/video/hi57CA3GZy4/видео.html As an addition, what prevents us from moving at the speed of light is mass. If we were without mass, we would travel at the speed of light, but we couldn’t use a single physics statement. It would make no sense. Like the rules of backgammon will never explain chess.
The reviewed video is pretty much gibberish; that being said mass doesn't increase at relativistic speeds. Relativistic mass is a thing, but it has more to do with the total energy of the system, versus invariant mass. Also, to clarify, any faster than light travel implies time travel. You could arrive back where you started before you leave. Check out light cones and closed timelike curves.
Faster than light travel of the type being presented here are space like curves. Timelike curves that can approach themselves are more likely to happen near extreme gravity sources like the inside of a black hole.
I might be wrong, but even if I were to travel faster than a speed of light, if I see things happening in the past that doesn't mean that I'm traveling back in time. Even now we're observing things from the past (light emitted by stars) and we're not traveling close to the speed of light
You should "leak" this video to flerfs, making it look like you don't want them to know it exists. See what they do with the revolutionary information it contains! :P
Wow, there is more scientific accuracy in an episode of the original Star Trek series than in their video.
Absolutely! The deflector dish on all of the starships solves many of these problems...
“Scotty ta’ bridge!
Im givin’ her all I can Cap’n
She’s on warp nine now!
If I push her any more, she’s gonna blow the phase converters and I’ll have to change the dilithium crystals!”
@@jbirdmax And his underwear - assuming that Scotty isn't wearing a kilt!
Haha! Eww but haha 😂
Yup. Even back then they coined their propulsion method warp, implying that a warping or bending of space time occurs.
The enterprise never exceeds the speed of light or gets even close to it (I think typically full Impulse speed, essentially a fancy rocket propulsion) gets you to 0.25%.
What happens instead, even though they never spelled it out in TOS, is the engine somehow contracts the space in front of the ship reducing the distance to a hop and a skip.
There are a couple of instances in the franchise’s literature corner where ships had to go relativistic because warp wasn’t working for whatever reason, and they accelerate the ship with Impulse to .9c.
As a result they were able to cross vast distances in the range of light years within a few months of their own time perception.m, but skipped a century from any outside observers.
Okay, so a physicist here (well, at least by education, and relativity was always the part of physics that interested me the most).
8:50 Basically, the relativistic mass changes by the same factor by which time is dilated, which is 1/sqrt(1 - v²/c²), so if time slows down twice, mass increases twice. Although the relativistic mass itself is a bit of a controversial thing - it is being taught as a consequence of special relativity, and relativity does imply changes in inertia as objects accelerate, but physicists in academia tend to treat the rest mass as "the mass", and ignore relativistic mass as a notion, for multiple reasons which I won't list here, because a RUclips comment isn't the best place to do so.
9:54 The velocity would be (0.9+0.9)/(1+0.9*0.9) = 1.8/1.81 = 0.994 c, so you got it right 😉
11:48 As for exceeding the speed of light - while you're right that within special relativity it's impossible for a massive object to reach the speed of light or exceed it, it does make some limited sense to consider frames of reference exceeding the speed of light. So for a thought experiment, we can imagine the rocket and people on it being converted to tachyons and going faster, and the math of special relativity still works... at least to some extent.
12:34 The thing with cause and effect is a bit more complex. The thing is, some cause and effect relationships would be reversed, and some wouldn't. This is because whether you're travelling forwards or backwards in time starts to... depend on the observer. If you imagine multiple "normal" observers obeying the c speed limit, depending on their relative speeds, some would see you going in one direction and forwards in time, and some would see you going the opposite direction and time in your rocket flowing backwards. And some would see you as a weird object moving at an infinite velocity that just materializes for one instant and disappears the next. Again, it's a bit hard to explain how this is possible in a comment, unfortunately, so I'll have to leave it at that for now 😅
13:13 Again, that depends on the observer. To _some_ observers, you _would_ be travelling backwards in time. But to others, you wouldn't be. And these observers would all be moving forwards in time relative to each other. It might sound kind of self contradictory, but I assure you that it isn't! 😅
14:25 Yup, that's a big problem. At fast enough speeds, regular light from stars would be blueshifted so much that it would become harmful. Also, the intensity of the light you're receiving from the front grows as you accelerate, so it gets blueshifted _and brighter,_ further exacerbating the problem.
Anyway, don't take the above points as criticism. I still think your video is very good, and the video you're addressing mixes truth with fantasy in an awful way, so it's great that you're pointing it out. Definitely a thumbs up from me 👍 (for you, not the other guy(s) 😁)
I'm no physicist, but I know a decent bit about length contraction near the speed of light, and I know the lengths of items approach zero as you get closer to the speed of light, so wouldn't going ftl flip your rocket in the opposite direction?
@@Stingpie That's an interesting question. I guess that can depend on how exactly you're going to accelerate past the speed of light, because you can't really do this continuously starting from a sub-light speed. It does seem, though, that expecting the rocket to get flipped backwards makes some sense.
Then there is the problem that the direction along the rocket for you would be a timelike direction in the frame of the rocket, so that also complicates things a bit.
Simultaneity gets really weird with relativistic effects, doesn't it?
I always wondered if, since the length contraction seemed to only be in the direction of travel with none on the other two dimensions of space, is it sort of like you're trading off a space dimension for another one at 90° to it? I picture the two dimensions like the _x_ and _y_ axis on a grid, with a plot approaching zero in one coordinate while asymptotically approaching infinity for the other, and vice versa when the two are swapped.
It so easy to diagram what I mean, hard to concisely put it into words.
@@bobblum5973 "is it sort of like you're trading off a space dimension for another one at 90° to it?"
Kind of, but not quite.
Lorentz transformation - which is the basis behind relativity - is very similar to rotations in some aspects. So when an observer travels in the x direction relative to another observer, it's a bit as if his spacetime coordinates were rotated in the x-t plane relative to the other observer's coordinates. And then time dilation and length contraction are kind of similar to foreshortening - for example if you measure some time interval, it's kind of like a line segment along your t axis, and since it's rotated relative to the other observer's t axis, its length along the other observer's axis is slightly different.
But it's not _quite_ rotation. If it was, time dilation and length contraction would be the other way round, that is: time would flow faster for moving observers, and moving objects would appear longer. You can imagine rotations as going in circles around a point - Lorentz transformations are then like going in _hyperbolas._ And where trigonometric functions are used to describe rotations in equations, they get replaced by hyperbolic functions in Lorentz transformations.
This would also be easier to see on a diagram, but I won't risk this comment disappearing by posting a link 😅
Saying this as someone who used to have this misconception: Another danger with sites like that is that when they get science wrong and scientist correct them, to the layperson I can look like science doesn't know what they think. Which created the opening for ever scientific conspiracy theory from flat eart to YEC to antivax
Well, lucky for us all than that Theism and atheism
are so big that they spawned many YT-Channel diving into it without Bias:
The Atheist-Channel.
Some polite, some funny, some serious, some goofy:
Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale
and Atheist Jr. All worth cheking out.
Only if said lay person doesn't understand that such a youtube video is extremely likely not made by a scientist...
Yeah, a lot of people expect science to be ... well an exact science and have all the answers. When in fact science is made up of a series of theories with a basis and evidence, and everyone is constantly trying to prove eachother wrong. There is no 'big science' somewhere deciding what we all study and think. There's just the general consensus of which theory has the most credibility.
Ridddle gives the aura of a trustworthy source of science data, but their videos are always absolutely chocked full of data. It’s actually pretty fun to watch them and see how many mistakes you can count- just don’t make a drinking game out of it, you’d end up having to get your stomach pumped.
There is a short sci-fi movie, that perfectly explains this "travel back in time". In it humanity sends a ship to travel faster than light, and so far away, that when he looks back at Earth (which in his time (year 2XXX) is reddish, dust covered desert), he sees her as the planet we have today - covered in oceans and forests. He didn't travel back, he just traveled further, than the light from his time.
Only problem is, he outran that light He would have to wait---years? centuries? Millennia? Depending on how fast he was going (assuming that was even possible...which as far as we know it isn't). Light from the past would catch up first, but he would still probably have to wait a long time.
@@jayfredrickson8632 He outran the light from his time, and was seeing light from 100 years ago or so. Unless he traveled more than 4,5 billion light years, he would see the Earth.
There was a flat Earther named Mike
Who could travel faster than light
He left one day in a relative way
and came back the previous night
@@ivanpetrov5255 Of course he would see the earth. I never said he wouldn't. Maybe I misunderstood what was meant.
@@jayfredrickson8632 Or maybe I explained it poorly 😄
Another nitpick: Even if you're looking directly backwards, at 10% of the speed of light, the stars would not appear red. They might look a little more yellowish-white than usual, but that's about it.
Because _all_ light is frequency shifted, that also means that the UV light the stars are emitting also gets shifted to become blue light as well, so you still end up seeing a full range of visible light (white light) from the star, there's just less UV light (and more infra-red), and the peak emission wavelength shifts a bit (so it might change its tint a little bit more yellowish).
You'd actually need to get to somewhere around 50% of the speed of light before things would really start looking visually red (behind you), because that's around the point that the UV/blue emissions actually drop off enough that the majority of the visual light you see would appear to be in the red end of the spectrum.
I was waiting for someone to point this out
because we actually detect Doppler shift through comparison of frequencies (there literally isn't any visible color difference, at least to any measurable degree, in the (albeit slower) stars we see)
Red shft and blue shift is kind of misunderstood. Some think that all you move away from, turns red. That's NT te case. The color spectrum turns TOWARDS red.
For example, at slower speeds, something that is blue turns teal, then green at higher soeed, then yellow etc.
And it's not single colors. It's a spectrum of colors, depending of the composition of the material or rather matter.
Some polite, some funny, some serious, some goofy:
Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale
and Atheist Jr. All worth cheking out.
@@nenmaster5218 I agree, yeah, and would add AronRa and Viced Rhino to that group (even Gutsick Gibbon!), but this really looks like it belongs on another comment.
Usually, the reason going faster than the speed of light is bad is because your headlights wouldn't work anymore.
Last time I checked spaceships didn't have headlights.
@@maxine_q My understanding of physics (and reality) is based on Bugs Bunny and Road Runner cartoons.
Actually, because relativity, they would - but nothing else around would
@@maxine_q I'll have you know I put headlights on all my spacecraft. Well, they're craft, so they're called running lights.
But your tail lights would now be shining forward.
The formula for adding velocities is (u+v)/(1 + uv/c²), so adding u=v=0.9 does give 0.994+.
A popular treatment of relativity I read as a lad stated that there's no way to know what would happen to a ship that went faster than light, and simply said that such a craft could travel to Oz for all we know. That was definitely more accurate than this muddle.
I mean we have the theory of relativity that tells us what happens. The theory would allow for tachyons to exist. A Tachyon is a particle that will always move faster than the speed of light. If you add energy to a tachyon it will slow down and if you add an infinite energy to it, you could slow a tachyon down to the speed of line. If a tachyon losses energy it would speed up. Also Tachyons would always travel backwards in time and would have a negative mass. Obviously those are only a mathematical solution to the theory of relativity and there is no proof those particles actually exist. But this does suggest that a rocket above the speed of light would behave similar to tachyons although there is no mathematical solution to movement faster than the speed of light with a positive mass if I'm not mistaken.
@@Taktikameise Tachyons wouldn't have a negative mass, but rather an imaginary mass. Also, what is faster than light for one observer is backwards in time for another. As another poster has mentioned, if we have both relativity and FTL, then we lose causality.
@@tomkerruish2982 Yes my bad When I read about it the square of the mass was mentioned, not the actual mass and if that one is negative the mass has to be imaginary.
Also it is unlikely they exist. Because they would be able to create your basic timetravel paradox. Like what happens if you message yourself with Tachyons to not message yourself with tachyons.
Theory of relativity has other interesting mathematical solutions like White Holes, but to be fair the theories around them are a bit too high for me.
If Einsteins GR math is valid AND something could break the speed of light a spaceship could traverse certain paths through spacetime that lead back in time. But all the paradoxical things that are associated with these ideas/stories are just hints that our mathematical description of reality stopped working. Reality has no paradoxes, our (limited) understanding of reality creates them.
"Causality, Relativity, Faster than Light travel... choose two of three."
Be able to exceed the speed of light would break general relativity, so you can't have both.
@@RichWoods23 I think what the OP was indicating is that a universe could only have 2. If you take relativity and FTL, causality could not be Kemptville by the implication of VTL and relativity. If you take FTL and Causality, relativity would have to be thrown out. Our universe has Causality and Relativity, FTL isn’t an option because of that.
@@RichWoods23 FTL is technically possible under general relativity through stuff like wormholes right? It's just that when you combine FTL with time dilation under relativity it allows for time travel, breaking causality.
That video went wrong pretty early, but the bit about the astronauts own watch slowing down was particularly egregious.
They really don't understand any of this, do they? They read another popular science article and failed to get any of it, then thought, "hey, let's make a video about it, it'll look cool"
People always misinterpret the "Time slows down" part horribly.
You might say it was... Ridddled with errors. YAAAAAAAAAAAAAAAAAAHH!!
You forgot to put your sunglasses on
For me, the best explanation of relativity is from the movie Deep Blue Sea.
"Grab hold of a hot pan, second can seem like an hour. Put your hands on a hot woman, an hour can seem like a second. It's all relative."
That's close to what Einstein is reputed to have said
@@stephenlitten1789 Yeah, I was told as a kid that Einstein had something something to the affect of "put your hand on a hot furnace and a second feels like an hour. Put your hand on a hot woman and an hour feels like a second". Whether Einstein was the one who originally said that or not, Deep Blue Sea didn't invent it :P
I appreciate the humor (and forgive me if this was meant purely as a joke/sarcastically), but this is obviously one of the worst possible ways to explain relativity (because it's extremely misleading), or I guess more properly, it's just not an explanation of relativity. It has absolutely nothing to do with general or special relativity, doesn't really describe frames of reference, and most especially, it's a misleading description of a phenomenon totally unrelated to relativistic time dilation, which might cause the listener to misinterpret what time dilation even is.
@@ByzantineDarkwraith Right on all fronts. Unfortunately, I'm unaware of any short and pithy explanation of relativistic time dilation. I do remember seeing a video many years ago (BBC, maybe) that explained it in a few minutes. There are a few on RUclips which may be what you are after.
“It is impossible to travel faster than light, and certainly not desirable, as one's hat keeps blowing off.” -Woody Allen
10:37 Meanwhile, what are 'atomised atoms'? And why are they on the same scale as a speck of dust?
I think they were trying to refer to _ionized_ hydrogen (as opposed to molecular hydrogen).
"Unless of course you have the time stone...but that has been destroyed."
Take my like for this casually random reference before I even finished watching.
The part where you mention its impossible to go F.T.L
reminds me of a line from a filk song where someone goes the speed of light and then all of his family, friends and future generations die
"You know someday your gonna win that race and fly back the years to your starting space"
Riddle's video should be classified as fantasy. To be Sci-Fi I'd prefer to see some attempt at believability. To be popular science I'd like some explanations rather than just jumping to wild claims. E E Doc Smith he isn't.
Some polite, some funny, some serious, some goofy:
Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale
and Atheist Jr. All worth cheking out.
Don't rush the ahoy-hoy! Some of us only kept watching you because of that signature intro. 😁 (watching since 2017)
I saw this video on my own a long time before watching your response, and I was so frustrated with how casually inaccurate it was!
Ridddle is one of those catchy headline channels that is providing videos riddled (pun intended) with plenty of misinformation and half-assed "facts". It should be taken with more than just a grain of salt.
The first thing they get wrong is that condescending waffle presented in that 80's video trailer voice.
Also, remember folks, mass is Lorentz-invariant, implying that it does not change with the velocity of the corresponding object.
That video has massive "we have Kurzgesagt at home" energy
If Planarwalk said "math" I wouldn't be able to watch this because an infuriating OCD aspect I have, is to say out loud "maths" to correct it.
it's maddening!
What I find kind of strange is that we've abandoned the idea of a 'universal clock' because of general relativity, but if you think about it there still is a sort of standard clock, which started at the big bang, but then different areas of spacetime tick at different speeds. Framed like this, you can never go back in time but you can travel forward at different speeds.
it isn't that different areas tick at different speeds (excluding gravitational time dilation here since we are talking about cosmology), it is that observers moving at different velocities perceive different time speeds *for the other observers* (a observer is always at rest in their co-moving frame of reference).
the age of the universe is given in the frame at rest relative to the galactic fluid (i.e. the sum total of the galaxies is at rest, even if individual ones still have some peculiar motion).
combining that system with the assumptions of isotropy & homogeneity leads to the FLRW-metric, and the Einstein field equations simlify to only two equations, the friedmann equations, which are used to derive the age of the universe.
If you are now moving with a velocity relative to the galactic rest frame, the time in the galactic rest frame appears to move slower, meaning for you the universe appears older.
@@freyja5800 You seem very well educated on this, so perhaps you could clear up a bit of confusion I'm having. I was wondering why, when someone is travelling in a rocket at 50% of light speed or whatever relative to the Earth, time in that reference frame moves slower, rather than the other way around. The reason this confuses me is because I've heard that there is no such thing as "absolute motion," and all motion is relative. Therefore, isn't the fact that, in the rocket's frame of reference, the Earth is travelling relative to it at 50% of light speed, just as valid as the fact that the rocket's moving at that speed in the Earth's frame of reference. Since either of them is moving at 50% of light speed relative to the other, and which one's moving just depends on which frame of reference you're looking at, why is it that time dilates in one of those specific reference frames, and it's not the other way around? Basically, how does the universe "choose" (I know it's obviously not an actual conscious choice) which reference frame experiences time dilation relative to the other, when they could both be considered to be moving at 50% light speed (depending on the reference frame chosen)?
@@ByzantineDarkwraith the source of your confusion is miscommunication. you are absolutely right, there is no preferred reference frame, and while for people on earth the time in the rocket seems to slow down, for the people in the rocket time on earth seems to slow down. combining this with the length contraction results in the conclusion that simultaneity of events is frame dependent (i.e. 2 things happening simultaneously in one frame might happen at different times in another reference frame).
If you want to know more about that I would recommend looking into minkowski diagrams (spacetime diagrams for special relativity), and how you represent different reference frames in them.
As for the rocket, the coordinate time is not a lorentz scalar, meaning it is not invariant under coordinate transformations. for that you have to look at the proper time, which is independent (and related to the spacetime trajectory of a given thing). proper time also explains why if the rocket where to turn around at some point, there would be an actual difference that is frame independent, and the difference is essentially caused by the acceleration needed to turn around.
(I should note however that I mostly deal with simulations etc, and I haven't really dealt with relativity for a few years, so it might be inaccurate on the finer details)
@@freyja5800 I am no where near being called a physicist or scientist, but in the example above, wouldn't time on earth appear to be going faster for the observer on the rocket? Not slower?
Another question I have. I understand that science has discovered that the universe is expanding in some places faster than the speed of light. With this being the case, couldn't theoretical FTL travel be possible "frame shifting"? In other words, could we shift our occupied frame using conventional acceleration, but shrink or expand space around our frame?
@@seanwolfe5161 sorry for the late answer
for the questions:
1: no, as byzantine pointed out, there is no preferred frame in the universe, so the effects have to be symmetric in that sense (i.e. the moving thing experiences slower time, no matter which (earth or rocket) is moving & stationary)). Yes, that is kind of counterintuitive, but that is why I recommended minkowski diagrams, b/c they can help illustrate it.
basically, in a 1+1D version (1 space, 1 time), in any given frame, the time and space axis are vertical & horizontal for itself, with lines of simultaneity being parallel to the space axis. when marking the time and space axis of another reference frame moving at a velocity & with a shared origin (i.e. a pure lorentz boost), both the time and the space axis of that frame as viewed from the current frame are angled towards the line of lightspeed (light is at a 45° degree angle), and the lines of simultaneity are also parallel to the space axis of that frame.
this means that events that are simultaneous in that frame are not in your own, and if you draw the simultaneity line for a given T, for your T the corresponding time is the time on the slanted time axis at the same hight (on a line of simultaneity) and is smaller than T, but if you take the time T of the moving frame, and draw *their* line of simultaneity, due to the slant of their space axis it intersects your time axis below T, meaning for them, your time moves slower.
as for the second question: the expanding faster than c is a direct consequence of the fact that the expansion rate is uniform everywhere, and it usually is given in km/s/mpc (kilometres per second per megaparsec, current vallue ~70km/s/mpc), if you have a distance far enough away, it will be faster than the speed of light.
this isn't really something that can be controlled, since it is a cosmological phenomenon, and thus only applies on scales beyond galaxies, and cannot be influenced anyways.
but the idea of using expanding/contracting spacetime to achieve FTL is indeed allowed by einsteins formulas, with probably the first version of a metric based on that given by Miguel Alcubierre (called the Alcubierre metric after him), but it requires exotic matter to work sadly, so probably will never be possible outside of science fiction.
The Heartless Act is chilling nicely.
I hate videos like the one you featured. It's like they tried to dumb it down and then the concepts got mistranslated in the process making them inaccurate and in some cases just plain wrong.
Good on you on calling this one out. I agree with your critisisms and corrections.
If you get bombared with gamma rays, you turn into the Hulk and can snap the gauntlet of Infinity Stones.
Thanks for highlighting this problem
Top 20 aint bad, I was at work when it came out. I enjoy the space themed videos you've done recently, I love it. May I suggest looking at sciences of going to Mars and videos about all that? Cause there's lots of issues with going to any planet that videos like these gloss over
Ah yes, Ridddle! I used to subscribe to them, until one video (not this one) was just too full of errors, and I had to drop that channel. It’s a shame to see that some things don’t change. In case you’re wondering, you’re spot on about the time dilation calculation. To have time move at exactly half the rate that it’s observed for a stationary object, the spacecraft would need to travel at square root(3/4) of the speed of light, approximately 86.6%. Ridddle - close enough if you forget things easily, but wrong enough if you have any memory at all.
BTW, here’s an actually good video about why traveling near the speed of light would suck, from Cool Worlds:
m.ruclips.net/video/b_TkFhj9mgk/видео.html
One interesting factoid (at about 14:45 in the video): As you travel ever faster, the Cosmic Microwave Background radiation will blue-shift into visible wavelengths, then into even higher, more unpleasant intensities. Ouch!
My 5 year old watches terrible RUclips videos where they posit a “what if” and explain what would happen if that what if we’re true. Like, “what if the earth split in 2”. They then proceed to make up nonsense that would definitely not happen. I say all that to say, this video reminds me of those videos
I guess we found out what Kurzgesagt would be like if they had no idea what they're talking about.
Dummgesagt
Yeah, I watched this episode and part with rocket backing into starting position left me completely confused.
They don't make time machines like they do in the future.
I read your comments many yeas ago. I'm back in time now, to confirm you're absolutely correct.
@@akyhne ⏰🕰🕑You are resynchronising ⏲🕖
if a rocket blasts away from earth at the speed of light, then according to their reference frame, it would be the earth that moved away from them at the speed of light, and therefore, everyone on earth would experience the same time shifted magical temporalportation of reversity.
crazy how information is processed in the physical universe. Reminds me of animals' different perceptions of time.
It sounds like a take on the Star Trek Voyager episode where they go to Warp 10 and time stops making sense to Tom Paris as he devolves/evolves faster.
Yeah I nearly had an aneurism watching that video.
The most painful part for me was as soon as they said that the clock on the wall of the spaceship would start to slow down as seen by the passenger on the spaceship.... I couldn't help but pause the video and exclaim out loud to myself "no no no no no!", because it became apparent (well more apparent) that they didn't have even a basic understanding of what they were portending to educate people on. I then resumed the video and cringed the whole time (well except at Planarwalk's content).
Now if they had specified that the clock on the wall of the spaceship would appear to slow down as viewed by a (relatively) stationary observer looking in a window of the spaceship as it flew by (ignoring the fact that they would never be able to see anything with it moving that fast, but regardless demonstrating the relative change in the flow of time), then that would be correct. Or say that the person on the spaceship, looking out the window at a clock tower as they flew by (again ignoring the problem of perceiving it at that speed), they would see it ticking faster than normal.
Knowing about time dilation is much like knowing how to kill a vampire. 😆
Even waaaaaaay before you got to the speed of light, the CMB would blueshift to billions of degrees Kelvin, so you would turn into vapour far before you even got there.
a couple corrections to your understanding:
3:00: this is actually not true, the light reaching you is not the same, you get one second worth of light every second. This is because even though you are moving, the light from the clock is still moving at the speed of light. The cause of the slowing down is time dilation, causing the emitted light to be always very similar because changes in the clock are very slow from your perspective. And this also applies when approaching the clock, this is intuitively not obvious but still true, think of the decay of muons from cosmic radiation, they go straight towards you but still their lifetime is longer than would be expected. Your arguments are the first part of the cause of blue/redshift seen by you (the second part comes from time dilation, in acoustics there are different formulas for the doppler shift because of a moving observer or a moving source, with light shifts these gets combined non trivially which incidentally means the shift in frequency of light is not quite symmetric when approaching or receding from a lightsource). Going "at" the speed of light doesn't change this, it's just the limiting case.
10:00: you are right the formula for addition of two percentages of the speed of light va and vb resulting in vt is vt=(va+vb)/(1+va*vb) so in this case would be (0.9+0.9)/(1+0.9*0.9)=0.9945
There's also the pesky thing with carrier particles, which move at the speed of light. You want all your atoms moving less than the speed of light if you want to keep your atoms together.
If you had infinite mass the whole universe would collapse on you.
Nice jobs throwing some shine on the flerfs!! 🤭👍🏼
A clock does NOT slow down as it travels at higher speed
Thanks! I enjoy your videos!
There are ways to tiptoe around the energy requirement to accelerate spaceship to the speed of light, or at least very close to it.
It's a one-way trip but we've observed the particles near the event horizon of black holes exceed 99% of light speed.
Good news about the space debris: once you achieve a certain relative velocity, we're not sure exactly what but somewhere just shy of light speed, all the dust and micrometeors will interact with your spaceship as if they were gamma rays - and the ship will interact like gamma rays to the dust. So, collisions become a non-issue... after you've accelerated past the point where they're a very big issue, because of the mass amplification effect making every bit of dust equivalent to slamming your ship into a planet. But if you do get past that point, yeah, radiation shielding and you're good to fly. You should really have that rad proofing anyway, since even at much lower speeds, the blueshifting of normal starlight ahead will turn it very extra deadly. But, details!
Hu-mans. Is that a nod to sir sick?
If you look out of the side windows of the space ship you will indeed see the stars red shifted. It's called the transverse Doppler shift. The equation for Doppler shift when looking in any direction is complicated and is seldom mentioned in books, unfortunately.
Causality would only be reversed for someone inside the ship from the point of view of someone outside the ship.
If you went faster than the speed of light you would appear to be going backwards -- that makes no sense, which is because it's impossible. Impossible things often don't make sense.
Ridddle is the type of channel that post a video saying that a nuke in the Mariana Trench would result in a planetary cataclysm.
I love the sir sic reference.
I checked here, and at 90% the speed o light, the mass would be 2.3 times that of the object at rest… fair enough…
Have you not heard of the infinite improbably drive ? Personally I blame the Vogons and there poetry . Remember boys and girls never travel without a towel
12:35 The reverse of causality would not be "just in the rocket", because... its all relative :P
For the people in the rocket, the rest of the universe is moving faster than light, so yeah, the universe would go backwards for them.
Interesting fact since speed is relative, from the prospective of some objects, we're constantly traveling at relativistic speeds.
Some polite, some funny, some serious, some goofy:
Prophet of Zod, Logicked, Belief It Or Not, Viced Rhino, Telltale
and Atheist Jr. All worth cheking out.
Looks like a Heartless Act there, doesn't it?
ah yes basic things like time dilation
Is it just me, or did anyone else get a "Jake the A--hole" vibe from Ridddddle?
the thing about time dilation fromula is that not only it's (1 - v^2/c^2), but a square root of that...
This makes the time when traveling faster than speed of light not negative, but imaginary...
(this is obviously wrong for many reasons, but I find it fun).
No complaints. Technically Eisenstein’s equation do have solutions to velocities greater than the speed of light but in out Universe that is unlikely to happen except in very unusual circumstances. Orbiting a rapidly spinning black hole for example could potentially create acceleration vectors that might make this possible but it’s all theory and had nothing to do with the video which you were reviewing. Great work btw, love your videos!!
But Dialga and Celebi still can do with time whatever they want😂 So no time stone needed
Ahoy hoy, Planarwalk, I watched this video thinking I was going to be confused and not completely understand what you were saying! And the clips that you showed of their videos made me completely understand what you were saying! I actually said, "No", after you showed their clips & before you made any comments! Which makes me really happy! Because I do enjoy your videos and I honestly think you are very, very intelligent! Thanks for your videos and keep up the good work!! Oh and something to do a video on, Creaky just released an awesome video on this melted guy, check it out, and maybe do a video too. Even if you don't do a video on this melted guy, I think you'll enjoy Creaky's video!! 👍🏼
A very good job. This physicist approves of the video!
TIL that kiwis prounounce "error" as "era". I was quite confused at first :)
about 2:50 - the observed clock would actually be stopped, no matter if you go towards or away from it. this effect does NOT take light movement into account - this operates on space-time slices.
the light reaching your eye effects apply on top of that
a note about 7:49 - it's not that time dilation applies to the whole ship, it's the opposite - time dilation applies to the whole rest of the universe, but you ship. the point is that for you - your reference frame is just as normal as any other observer's reference frame.
and it is this notion that you observe relativistic effects being applied to everything else, but another observer sees relativistic effects being applied to you - this is what causes so much misunderstanding and seeming paradoxes (not real ones, just caused by misunderstanding)
and again for 12:43 - as far as you can see inside the rocket - the rocket stays still, and the whole universe moves "faster than light" around it. And that's the point of SR - no reference frame is "better" or "more correct", there is no "main" reference frame
just a note on 10:04 - TECHNICALLY, specifically SR does not say that things cannot go faster - so technically math continues to work. it just the jump from subluminal to superluminal speed is what requires infinite energy and therefore seems impossible. so for all we know - there MAY be a whole set of superluminal particles living their own life (like tachyons), but they can never slow down to subluminal speeds. but that all is just what can be derived from math model, we have not actually observed such particles, nor we actually have idea how to (as far as i know)
13:48 - note, here we just operate with math equations, and speculate. here the the rocket ofc won't return, but the moment of rocket being still on earth will be "in the same now" with you - so it will be in the same timeslice with the flying rocket.... i know, this is indeed hard to have intuition about.
I quit game theory because of that. Well it was historical error. But that's science too.
I gave that channel a shot - the titles sounded interesting, but it's just kind of silly..
Honestly the only reason ridddle is so popular is because the guy sounds like Tom hanks.
Yeah I saw that video, and I was very infuriated xd. Somewhere in that comment section must still be a long passionate piece of all the misconceptions I found xd
You could also experiment Time Machine (sic) by getting to the top of a building, DUH !
Definitely not a nitpick to point it out!
Just saw a video today about how long it would take to travel to each planet, and one of the first things it says is, it took 6 days for Apollo to reach the Moon from Earth. I did a double take like, what the whaaaat?
There was a young lady named Bright
Who travelled much faster than light;
She set out one day
In a relative way
And returned on the previous night.
[Edit: I don't know the source.]
I think the timestone is the most scientifically accurate issue here. You can only use it to change the flow of time, but it's been destroyed. All facts no cap.
The Time Variance Authority has plenty of spare timestones. You just need to attract their attention somehow, then escape and grab one. Problem solved.
Light speed? Pffftt. Warp engines to factor 7. Engage.
Sometimes , I think people watch too many movies , and that would be o.k. ( I watch too many movies ) but then they go on to mix up their movie ideas with their science and that is not o.k. Science fiction is not the same as science .
12:11
It's like asking:
What would happen if 1 + 2 = 5
More information than this is required to answer, because our current universe can't account for this.
There's probably some abstract algebra you can invent to allow this.
But these new rules need to be declared to answer any hypotheticals.
And even then, the hypothetical only applies to the fictional abstraction you just invented.
I think the same person voice overing ridddle is the same person in arnold ones and the same person is also in the scp foundation ones 😂 it's always nice to watch these kind of videos. None the less, most of the things are rather entertaining to watch I myself being a physics student, without prove and proper visualisation I don't believe anything and these things aren't experiments which can be observed rather contradictions based on what we've seen and gain knowledge so far
In logic we have an entailment that says anything follows from a false premise. So I can say "If the Earth is flat, all humans have green skin", and it's a correct entailment. That is, since the premise is false, I can make the conclusion. This of course also goes all humans do not have green skin, so we arrive back at false, namely the Earth is flat. - So "if we travel faster than the speed of light" - well any conclusion they make after that premise is a correct logical entailment
i really like ridddle but im supper happy to see someone debunk his video.... i dont always agree with what i see on his videos, i had a feeling he was getting some things wrong... thx dude... have you seen his flat earth video yet.....
3:00 i would argue that you couldn't see anything as if you're moving at the speed of light photons can't catch up with you.
0.03 of the speed of light.... we wish
Cause and effect would only be reversed in the rocket to outside observers. On the rocket they would observe the outside universe being reversed.
One other Issue with the Micrometeorites peppering the Shuttle going at light Speed, the Atoms of the Meteorites and your Shuttle don't have the Time to move out of the Way or deflect each other like you would normally see and expect, so they would fuse together. This nuclear Fusion would not be a good Thing for you.
"You can't go at the speed of light (in vacuum)" is a bit simplistic of a statement.
Yes, your local velocity will always be less than c. However, that doesn't mean you can't travel eg. from Earth to Alpha Centauri in less than 4 years, _from your own perspective._ It's impossible for you to travel there in less than 4 years from the perspective of observers on Earth (or on Alpha Centauri, for that matter), but _from your own perspective_ it is perfectly possible for you to travel that distance in less than 4 years (of your own time). There's no limit to how short your travel time can be. And yes, this even though your local speed never reaches c. (The solution to this seeming paradox is that, from your perspective, space contracts in the direction of travel, making the distance to travel, from your perspective, shorter. In fact, from a photon's own perspective travel time is always 0, and the entire universe has been contracted into a zero-width plane in the direction of travel.)
And yes, that means that if you then return to Earth, more time will have passed on Earth than for you. Over 8 years could have passed on earth, while for you only 1 year has passed. Or a week. Or a day. (Of course in practice you wouldn't survive the acceleration needed for this, but theoretically.)
So it would be more accurate to say that an external observer will never see you travel faster than c, nor will you ever measure your local speed as faster than c.
Well, kind of. General Relativity throws some spanners in the works there too. While local traveling speed cannot exceed c, from any perspective, the _distance_ between two objects can grow faster than c, even from an external perspective. GR doesn't forbid this (and it's the reason why the entire universe is larger than the observable universe. Most galaxies that exist in this universe are receding from us faster than c. And no, that doesn't contradict GR. On the contrary, GR predicts it.)
imagine you're running through a moving train carriage. to you, you're just running. to someone on the platform looking at you through the window, you are going 100mph... that's relativity kids. (thanks anthony burgess, who, spent more time on the analogy)
I think the funniest part is when the clock ***in the same room*** with the passenger slows down.
If anyone wants to know what physicists would actually think would happen if you went faster than the speed of light, you should look up the hypothetical particle tachyon.
I am sure someone else has said this but… you can travel faster than the speed of light using an Alcubierre warp drive. That is because the ship itself isn’t really moving. Space time has no speed limit as demonstrated by the expansion of the universe.
That guy talks about relativity but forgets the "relative" part of "relativity".
just an internecine squabble down at the local dungeons and dragons club about the impossible...
Wouldn't the clock of an observer traveling faster than the speed of light be Imaginary, rather than negative?
broke pop science: "time would go backwards"
woke people who know the formula: "time would be imaginary"
For those (still) interested, there is an excellent video about light and time: ruclips.net/video/hi57CA3GZy4/видео.html
As an addition, what prevents us from moving at the speed of light is mass. If we were without mass, we would travel at the speed of light, but we couldn’t use a single physics statement. It would make no sense. Like the rules of backgammon will never explain chess.
The reviewed video is pretty much gibberish; that being said mass doesn't increase at relativistic speeds. Relativistic mass is a thing, but it has more to do with the total energy of the system, versus invariant mass. Also, to clarify, any faster than light travel implies time travel. You could arrive back where you started before you leave. Check out light cones and closed timelike curves.
Faster than light travel of the type being presented here are space like curves. Timelike curves that can approach themselves are more likely to happen near extreme gravity sources like the inside of a black hole.
I might be wrong, but even if I were to travel faster than a speed of light, if I see things happening in the past that doesn't mean that I'm traveling back in time. Even now we're observing things from the past (light emitted by stars) and we're not traveling close to the speed of light
You should "leak" this video to flerfs, making it look like you don't want them to know it exists. See what they do with the revolutionary information it contains! :P