When I'm on a train in movement I see the ground moving relative to the train, and when I'm standing on the ground I see the train moving relative to the ground. However, when I'm on the train I can feel the acceleration of it relative to the ground, whereas in the ground I cannot feel its acceleration relative to the train, because of this I know that regardless of the frame of reference the truth is that the train is moving relative to the ground and not the other way around.
@CptnMatruz Earth is definitely much more massive than the train, so when equal and opposite forces act between them the acceleration of the earth will be negligible. If you had a really big train things would be more interesting. Of course the surface of Earth is not at rest, as shown by a Foucault pendulum.
@ozmoroid Very clever, I knew there was something of that, the train transmits its energy to the earth but since earth is so massive we don't notice its acceleration, the train on the other hand has less mass so by the equation a = F / m we would have a bigger acceleration.
@Trygve12345678987654 Well, my mom's mom spoke Norwegian, but none of her kids learned and therefore none of her grandkids, although I used to know the names of the Norwegian Christmas pastries. ;-)
So Oz, I'm going to play devils advocate, and also because this loophole still bothers me as well, and ask a dumb question. What if the Earth (hold your breath) is actually at rest like the Bible (yuck) says it is? Then technically the Michelson and Morley experiment wouldn't have found anything but that conclusion. Ok ok I know I know, the Bible is full of shit, but as scientists don't we have to admit that IS a possibility? Even ignoring what the Bible says, the Earth could be at rest.
@iFreeThinker The Hafele–Keating experiment supports the roatating Earth theory. Even before planes and modern relativity you'd have a hard time creating a theory, as reliable as Newtonian mechanics, which models the earth as stationary and has everything else orbiting around it.
@lfo98 Ah, I see now. I knew of the Hafele-Keating experiment, but was not aware they actually tested planes traveling in both directions, east and west. Yes, if planes traveling east and west were measured for their time dilation and if the Earth were not rotating, they should measure the exact same time difference. Thanks, I had never read that deeply into that experiment before!
@iFreeThinker Classically it would be difficult to explain a geostationary orbit without having the earth rotating. If the earth rotated in the ether then the Michelson-Morley experiment would have detected it. People tried assuming Earth dragged part of the ether with it, but that led to bizarre predictions that would be readily observed in telescopes but weren't. In the end, General Relativity say that you can consider Earth at rest if you want to.
@ozmoroid It's just that the equations of motion are so complicated as to be impossible to work out. That's why when NephilimFree was claiming Earth is at rest I asked him to provide the equations of motion.
If there is no "absolute rest velocity", then how is it impossible to travel faster than the speed of light, since such a condition would require a reference point to begin with.
Suppose our planet (the sun, the galaxy containing it, however far back you want to go out) is moving close to the speed of light. We could measure absolute velocity through how difficult it is to accelerate ourselves in different directions. (Do we move faster or get heavier?)
Imagine two observers are moving in opposite directions away from a third observer, and the third observer would perceive the first two as moving away at 2/3rds the speed of light.
However, the first and second observer would perceive each other to be moving away from one another at twice that - 4/3rds. That's 1.3x the speed of light. Since neither right nor wrong about who is moving at what speed, isn't there a problem here?
@WhiteDragon103 In relativity velocities don't simply add. If I'm A and B is moving away from me at speed u and C is moving away from B at speed v then C is moving away from me at speed (u+v)/(1+u*v) which is always less than 1.
@WhiteDragon103 It's impossible to travel faster than the speed of light relative to other nearby objects. Specifically you can never "outrun" a beam of light. In principle distant objects in the universe are receding away from us at faster than the speed of light due to the expansion of the universe.
@Faladrin For your first experiment they will experience different time differentials, the larger their accelerations and the longer the period they are being accelerated will result in a greater time dilation (as with the twin paradox). The plane experiment has been done (the Hafele–Keating experiment). The plane travelling east will be travelling faster than the clock on the ground, but not as fast as the clock going north as the rotation of the earth reduces the relative velocity...
@lfo98 - Image the earth is a perfect sphere and is not in orbit or rotation, it's just a floating sphere. The two clocks going around the planet should remain in sync with each other if they are moving at the same speed (although in a different direction). When the two return to their starting point they should match, but the third which remained stationary should be "ahead" in time due to SR. Do you agree?
@Faladrin Yes, but SR alone will not deduce whether the clock which remained stationary, for that you need to concider which clocks have been accelerated which is in the domain of GR. Also the earth in reality is rotating.
@lfo98 - Ok, I see now for my intentions I need to remove acceleration from the equation.
There is a large cube in space that is mass-less (the cube need not be real, it is here for reference). You are looking directly at the center of one of the faces of the cube and at the center is a man with a clock. Directly above at the edge of the cube is another man with another clock, and to the left is yet another man. We will call these men C, Y, and X.
@Faladrin Also at t=0 from your perspective the cube and C have velocity .25c directly right, X has velocity .5c directly right and Y has velocty .25c directly right and .25c directly down.
From C's perspective X and Y are approaching him with equal velocities .25c. After X and Y travel sufficiently to meet where C is located the clocks all emit a signal giving their current time.
From C's perspective should the clocks from X and Y match? Should they match from yours?
@Faladrin No they won't match becuase they all have different relative velocities (Y has 2^0.5c wrt velocity wrt you so it doesn't have the same relative velocity as X, you need to sum its velocity components with Pythagorus' theorum). If you see the cube as a cube, C, X and Y will see it as a rectangular cuboid due to length contraction. Are you trying to say that the cube is the perfect frame of reference?
@lfo98 - the cube is just useful as a point of reference to visualize the situation. It has no bearing on the outcome and need not be present for the situation to play out.
From C's perspective X and Y do have the same velocity. C does not perceive himself as moving, and within respect to himself both X and Y have the same velocity. You as the observer in a different inertial frame perceive C, X, and Y as all having different speeds though. Whose measure of velocity should be used?
Yeah, sorry you're right about X and Y velocities. Errm, I think the problem with your problem is synchronising the clocks at the beginning. They could all agree that when they crash into each other they crashed at a certain time after recieving a signal saying start clocks now, but if from your point of view they all recieve that signal at the same time, from their points of view the signals will arrive at differnt times (I think).
@lfo98 and actually from C's point of view maybe X and Y wouldn't have equal velocities. If reletavistic velocities can be added linearly as you switch frames it would be easy to have something travelling faster than the speed of light (two things approaching you at above 0.5c from opposite directions).
Can't you use relativity to find the perfect at-rest frame of reference? Wouldn't the perfect at-rest frame of reference be the one in which a clock runs the fastest?
@Faladrin The point is that anyones rest frame is perfect for them. The fastest the Greeks will see clocks run is in their rest frame, and the fastest the Latins will see clocks run is in their rest frame.
@lfo98 -- They will each perceive their clocks to be moving the same (to themselves) regardless if they are moving or not. Increased velocity doesn't just make clocks move slower, it makes us move slower, we would perceive time slower, cancelling out the effect for our own frame of reference.
My comment was stating that the universe does have a "perfect" frame of reference and you can use relativity to find it.
@Faladrin Due to the expansion of the universe and the nature of the expansion (there is no particular centre, the expansion is uniform about every point in the universe), the universe does not have a "perfect frame". The universe isnt just sitting there so it doesnt make sense to give it one particular frame of refrence.
@lfo98 - I disagree. There must be some velocity at which clocks move at their fastest. I guess there is no reason to prefer that frame of reference over others, but it would seem to be the most unique frame of reference. The only other "special" frame of reference would be the one achieved by moving at the speed of light, but since only light can do that, it seem a bit unattainable.
@lfo98 - time progresses slower the faster you move. Likewise, the slower you are moving the faster times progresses. So, if you were absolutely still clocks would move at their fastest rate. Relativity gives us the tool to find the frame of reference which truly is not moving.
Again, I'm not sure there is any real reason to prefer the frame of reference of absolute stillness, but it is a somewhat unique frame of reference.
@lfo98 - Lets do a thought experiment. You have three clocks all right next to each other, essentially at the same point in space. The three clocks take up some acceleration and de-acceleration such that they end up in a line with distance x between the first and second, and second and third (having chosen an arbitrary left and right with the first clock being on the left).
A person at each clock can measure the distance between themselves and the other two clocks and is able to send a signal giving his own time. Each person at each clock is therefor able to determine how much each clock is out of sync with their local clock.
Can we agree that each person will determine the same time differentials between the three clocks?
If so then can the three people agree as to which clocks moved?
@Faladrin - One note, the acceleration and decelleration were all in a single direction. They were not doing loops or anyting and they did not double back on their own path. They moved completely within the line that they ended up in and only in one direction.
@lfo98 - Here is a better thought experiment. Set this up just like the Michelson and Morely experiment, but rather than using light we use time. Three people at the equator sits with thee synchronized atomic clocks. One person gets on a plane heading due north such that he will circle the globe and return from the south. Another gets on a plane heading east and will return from the west. Will the two clocks which traveled match (after adjusting for a non-perfect spherical earth)?
@Faladrin for the east bound clock. You can tell the two clocks in the planes have "really moved" due to the accelerations invloved in flying a plane round the world. I still don't really know what you mean by perfect reference frame! GR predicts the fastest a clock will ever run is a non accelerating clock in 0 gravitational field.
Loved it. I finally understood the significance of the Michelson-Morley experiment (which I had read about nearly 15 years ago)! You have one sincerely grateful fan in India.
@bustermk2 that'll make a great bar joke when you have physicist friends!
I've got one btw: Heisenberg is speeding on the highway. Cops pull him over and ask him "you know how fast you're going?" he answers "nope, but I know exactly where I am"
When I first went through this in school my mind was blown !! I could'nt get my head to accept this !! Watch light from the ground, and from a moving reference and you mesure the same speed !! Man, but as we played with the concept and equations I ended up understanding well how it works, but its definitly a wierd notion to grasp !
The lake you threw the rock into was not placid, there were wavefronts moving toward the shore (right) before you threw the rock in. Since there was a velocity vector was there before the rock hit the water it makes sense that the wave would not expand symmetrically and would move toward the right since there was already a component of the velocity in that direction.
Regarding your third example with the ball and the paddle: You say "it's the ball doing the whacking", but why isn't the paddle going faster to the right? Where is the energy going?
@javaskin I assume that the paddle is much more massive than the ball. Therefore, it's change in speed is much smaller than that of the ball - small enough to be imperceptible in this vid.
@javaskin if you throw a baseball at a concrete wall the wall is not going to move let alone move faster, but the ball will still lose alot of energy. the energy can be lost due to friction with the air, and contacting the surface as well. just like how wood starts to get warm if you smash it a couple times with a hammer.
Modern physics is so counter intuitive that if you tell a lay man that it is possible to create the universe out of nothing due to Heisenberg Uncertainty Principal, they think your Bull$#*!ing them. But the miraculous quran has told us about the uncertainty principal 1400 years ago along with The Big Crunch and also The Ever Expanding Universe at the same time ;)
@ozmoroid Yeah in such great detail that is why it took 1600 years and non muslims to come up with QED. Then muslims try to say oh it is right here in the quran. LOL
Absolutely brilliant, I'll admit that as someone with little background in physics I had to watch the initial latin v greek section twice to make sure I was getting it but that just made learning a new concept all the more satisfying, thank you Oz.
Excellent video, clearly explained! I plan to cover relativity in one of my future astronomy series videos, but I doubt I could explain it so well... I'm looking forward to your next one!
I can't believe it! One day ago I told you to stop commenting on Desertphile's video and to get to work making one of your own because it's been way too long. I log in today and what do I see? Yippee!!!
Hmm, it's made me wonder if this is just coincidence or perhaps I've been imbued with unearthly psychic powers of persuasion.... Ozmoroid, send me all of your money within the next 24 hours! Man, I can't wait till tomorrow!!!!!
As said in video space in not a thing, plus light is not a wave neither a particle, all present assumption are just to console himself to provide some properties to make calculus.
we need to learn as human being more about that visible stuff.
Exellent video. A good refresher on relativety for those of us who haven't actually used it much after learning about it in advanced physics classes. Very well explained in an easy (well as easy as relatively can get) manner...
Now ask yourself what if the motion of any system is absolute? No interaction can alter the total quantity of motion of the system it can only alter the nature of the motion within the system.
This is, by far, one of your best videos yet. I don't think I have ever heard the basics of relativity explained so clearly or succinctly in the past.
I hope you'll continue to make videos like this one :)
Thanks for this video, from a physics geek. We need more physics explanations that everyone can understand. It's weird and counter intuitive at first glance, but not magic.
In physics there is not "right" frame of reference, but with light, there is. If two ships move relative to one another by the speed of light, they can either both be moving half the speed of light, but it may also be that one is stationary, and the other is moving by the speed of light. The other ship would then be having the slower time than the other. It all comes down to who did the acceleration. So to know who is "right", you have to check the history of speed changes.
I followed everything apart from the maths formulae presented by the latin and greeks.
I get that light is always travelling at the same speed relative to all points (in a vacuum) but could someone explain to me in layman's terms how, if that is true, we have red shifted & blue shifted light from stars moving towards or away from us?
oh... wait. Is it frequency of oscillation? Meh... But then, if I move quickly towards the red light, will it turn blue? Is the frequency changing?
@AnonEyeMouse Red-/blueshifting is because of the doppler effect. Simplified explanation: You're standing still, and I'm running away from you, carrying a flashlight, that's always pointing in your direction. A specific light wave, with a certain wavelenght, starts being sent out. Because I'm moving, the other "end" of the wave will be sent out from (ever so slightly) further away from you. The wavelength will therefore have been stretched out, making it "redder".
@AnonEyeMouse "But then, if I move quickly towards the red light, will it turn blue?"
Yes. The light will be shifted toward the blue side of the spectrum. That doesn't mean it'll shift so far that the effect can be seen without various measuring gadgets, unless you move *really* fast!
@TheRationalizer I thought so, though I could not believe my own conclusion. Colors changing because you're moving towards or away from the source somehow felt wrong, but it had to be right because of the doppler effect. If the doppler effect works for light from the stars, then why wouldn't it work for light from eveyday objects (assuming we could move at the speed of light) but then again I'm no scientist. So if I was moving very fast everything would turn blue and red?
This is the best description I've ever heard, and it makes it easier to understand. In fact, it's simpler than I was let to believe, and I can easily wrap my mind around this.
But I just want to make sure of something. If you are moving very fast away from a light source, then that light would be red-shifted, right? So then, the light that approaches you (who are moving away quickly) would be SLOWER than the speed of light between objects that are not moving relative to each other, right?
@Rationalific The red-shifted light isn't 'slower', it still moves at the same speed, but the waves are stretched out. This is an increase in the wavelength and a decrease in the frequency of the wave, but only from our perspective.
@Theophage Thanks a lot for the reply. But I still have questions. I'd really like to get to the bottom of this problem. So, imagine I'm moving away from a light source very quickly, and someone else is moving away from a light source only half as quickly as I am. I know that the light appears stretched (like the sound of a siren with the Doppler Effect) but shouldn't the stretched light seem "faster" to the one moving slower away from it, compared to me, who is moving much faster away?
@Rationalific Nope, not faster or slower. Relativity says that the speed of light is the same for all inertial observers. Since you are moving away from the light source faster than the other guy, you will see the light as red-shifted more than he will, but you'll both measure the speed of that light as the same.
@Theophage Thanks for clearing that up. It sort of didn't make much sense, but I guess since time slows down the faster you go, the slower time would make up for what should have been the slower speed of light, thus canceling it out and making it appear to be the same speed of light as always...or that's what I think. If I'm still wrong, feel free to correct me again! Thanks for the responses!
very excellent sir... i teach high school physics and you just handed me some nice material for tweaking the explanations of this weirdness than I have been using... always useful to have someone else summarize this stuff from a different perspective...
Another way to prove all of this directly is to just examine Maxwell's equations. Any derivation of the wave equation out of Maxwell's curl equations will be independent of any velocity. PRESTO! You just derived relativity, and you didn't need to bother with any gigantic interferometers.
Fantastic, I remember when I was tutoring a high school student to earn some textbook money. She asked me "what is a sound `wave`?" It was a simple enough question to answer. Then she asked "what is a light wave?".... Crap...
@ozmoroid And yet Reality has acted the exact same way for over 13 billion years, without interruption. Maybe we are the weird ones for not seeing Reality as perfectly normal and steadfast.
I'd like to thank you particularly for compressing 3+ years and 7 books into 11 minutes and 26 seconds of video (11:26 relative to me, of course!).
CephasBorg 1 day ago
Both amusing and informative. Thanks ozmiroid.
nelmonster1 4 days ago
gues what! im only 10 and i under stand this stuff! woopeee for me!
zartek1337 1 week ago
When I'm on a train in movement I see the ground moving relative to the train, and when I'm standing on the ground I see the train moving relative to the ground. However, when I'm on the train I can feel the acceleration of it relative to the ground, whereas in the ground I cannot feel its acceleration relative to the train, because of this I know that regardless of the frame of reference the truth is that the train is moving relative to the ground and not the other way around.
CptnMatruz 1 week ago in playlist Liked videos
@CptnMatruz Earth is definitely much more massive than the train, so when equal and opposite forces act between them the acceleration of the earth will be negligible. If you had a really big train things would be more interesting. Of course the surface of Earth is not at rest, as shown by a Foucault pendulum.
ozmoroid 1 week ago
@ozmoroid Very clever, I knew there was something of that, the train transmits its energy to the earth but since earth is so massive we don't notice its acceleration, the train on the other hand has less mass so by the equation a = F / m we would have a bigger acceleration.
CptnMatruz 1 week ago
You seem like you're great at explaining! I wish I was better at English or that you spoke my language so I could understand this :D
Trygve12345678987654 1 week ago
@Trygve12345678987654 Well, my mom's mom spoke Norwegian, but none of her kids learned and therefore none of her grandkids, although I used to know the names of the Norwegian Christmas pastries. ;-)
ozmoroid 1 week ago
So Oz, I'm going to play devils advocate, and also because this loophole still bothers me as well, and ask a dumb question. What if the Earth (hold your breath) is actually at rest like the Bible (yuck) says it is? Then technically the Michelson and Morley experiment wouldn't have found anything but that conclusion. Ok ok I know I know, the Bible is full of shit, but as scientists don't we have to admit that IS a possibility? Even ignoring what the Bible says, the Earth could be at rest.
iFreeThinker 2 weeks ago
@iFreeThinker The Hafele–Keating experiment supports the roatating Earth theory. Even before planes and modern relativity you'd have a hard time creating a theory, as reliable as Newtonian mechanics, which models the earth as stationary and has everything else orbiting around it.
lfo98 2 weeks ago
@lfo98 Ah, I see now. I knew of the Hafele-Keating experiment, but was not aware they actually tested planes traveling in both directions, east and west. Yes, if planes traveling east and west were measured for their time dilation and if the Earth were not rotating, they should measure the exact same time difference. Thanks, I had never read that deeply into that experiment before!
iFreeThinker 2 weeks ago
@iFreeThinker Classically it would be difficult to explain a geostationary orbit without having the earth rotating. If the earth rotated in the ether then the Michelson-Morley experiment would have detected it. People tried assuming Earth dragged part of the ether with it, but that led to bizarre predictions that would be readily observed in telescopes but weren't. In the end, General Relativity say that you can consider Earth at rest if you want to.
ozmoroid 1 week ago
@ozmoroid It's just that the equations of motion are so complicated as to be impossible to work out. That's why when NephilimFree was claiming Earth is at rest I asked him to provide the equations of motion.
ozmoroid 1 week ago
Question-
If there is no "absolute rest velocity", then how is it impossible to travel faster than the speed of light, since such a condition would require a reference point to begin with.
Suppose our planet (the sun, the galaxy containing it, however far back you want to go out) is moving close to the speed of light. We could measure absolute velocity through how difficult it is to accelerate ourselves in different directions. (Do we move faster or get heavier?)
WhiteDragon103 2 weeks ago
@WhiteDragon103 Cont...
Imagine two observers are moving in opposite directions away from a third observer, and the third observer would perceive the first two as moving away at 2/3rds the speed of light.
However, the first and second observer would perceive each other to be moving away from one another at twice that - 4/3rds. That's 1.3x the speed of light. Since neither right nor wrong about who is moving at what speed, isn't there a problem here?
WhiteDragon103 2 weeks ago
@WhiteDragon103 I'm guessing that time dilation is required here to resolve this. :P -plots time-space graphs-
WhiteDragon103 2 weeks ago
@WhiteDragon103 In relativity velocities don't simply add. If I'm A and B is moving away from me at speed u and C is moving away from B at speed v then C is moving away from me at speed (u+v)/(1+u*v) which is always less than 1.
ozmoroid 1 week ago
@WhiteDragon103 It's impossible to travel faster than the speed of light relative to other nearby objects. Specifically you can never "outrun" a beam of light. In principle distant objects in the universe are receding away from us at faster than the speed of light due to the expansion of the universe.
ozmoroid 1 week ago
@Faladrin For your first experiment they will experience different time differentials, the larger their accelerations and the longer the period they are being accelerated will result in a greater time dilation (as with the twin paradox). The plane experiment has been done (the Hafele–Keating experiment). The plane travelling east will be travelling faster than the clock on the ground, but not as fast as the clock going north as the rotation of the earth reduces the relative velocity...
lfo98 3 weeks ago in playlist Physics
@lfo98 - Image the earth is a perfect sphere and is not in orbit or rotation, it's just a floating sphere. The two clocks going around the planet should remain in sync with each other if they are moving at the same speed (although in a different direction). When the two return to their starting point they should match, but the third which remained stationary should be "ahead" in time due to SR. Do you agree?
Faladrin 3 weeks ago
@Faladrin Yes, but SR alone will not deduce whether the clock which remained stationary, for that you need to concider which clocks have been accelerated which is in the domain of GR. Also the earth in reality is rotating.
lfo98 3 weeks ago in playlist Physics
@lfo98 *deduce which clocks have remained stationary
lfo98 3 weeks ago in playlist Physics
Comment removed
Faladrin 3 weeks ago
@lfo98 - Ok, I see now for my intentions I need to remove acceleration from the equation.
There is a large cube in space that is mass-less (the cube need not be real, it is here for reference). You are looking directly at the center of one of the faces of the cube and at the center is a man with a clock. Directly above at the edge of the cube is another man with another clock, and to the left is yet another man. We will call these men C, Y, and X.
At t = 0 all three clocks read the same.
Faladrin 3 weeks ago
@Faladrin Also at t=0 from your perspective the cube and C have velocity .25c directly right, X has velocity .5c directly right and Y has velocty .25c directly right and .25c directly down.
From C's perspective X and Y are approaching him with equal velocities .25c. After X and Y travel sufficiently to meet where C is located the clocks all emit a signal giving their current time.
From C's perspective should the clocks from X and Y match? Should they match from yours?
Faladrin 3 weeks ago
@Faladrin No they won't match becuase they all have different relative velocities (Y has 2^0.5c wrt velocity wrt you so it doesn't have the same relative velocity as X, you need to sum its velocity components with Pythagorus' theorum). If you see the cube as a cube, C, X and Y will see it as a rectangular cuboid due to length contraction. Are you trying to say that the cube is the perfect frame of reference?
lfo98 2 weeks ago in playlist Physics
@lfo98 - the cube is just useful as a point of reference to visualize the situation. It has no bearing on the outcome and need not be present for the situation to play out.
From C's perspective X and Y do have the same velocity. C does not perceive himself as moving, and within respect to himself both X and Y have the same velocity. You as the observer in a different inertial frame perceive C, X, and Y as all having different speeds though. Whose measure of velocity should be used?
Faladrin 2 weeks ago
Yeah, sorry you're right about X and Y velocities. Errm, I think the problem with your problem is synchronising the clocks at the beginning. They could all agree that when they crash into each other they crashed at a certain time after recieving a signal saying start clocks now, but if from your point of view they all recieve that signal at the same time, from their points of view the signals will arrive at differnt times (I think).
lfo98 2 weeks ago
@lfo98 and actually from C's point of view maybe X and Y wouldn't have equal velocities. If reletavistic velocities can be added linearly as you switch frames it would be easy to have something travelling faster than the speed of light (two things approaching you at above 0.5c from opposite directions).
lfo98 2 weeks ago
Can't you use relativity to find the perfect at-rest frame of reference? Wouldn't the perfect at-rest frame of reference be the one in which a clock runs the fastest?
Faladrin 4 weeks ago in playlist Uploaded videos
@Faladrin The point is that anyones rest frame is perfect for them. The fastest the Greeks will see clocks run is in their rest frame, and the fastest the Latins will see clocks run is in their rest frame.
lfo98 4 weeks ago in playlist Physics
@lfo98 -- They will each perceive their clocks to be moving the same (to themselves) regardless if they are moving or not. Increased velocity doesn't just make clocks move slower, it makes us move slower, we would perceive time slower, cancelling out the effect for our own frame of reference.
My comment was stating that the universe does have a "perfect" frame of reference and you can use relativity to find it.
Faladrin 4 weeks ago
@Faladrin Due to the expansion of the universe and the nature of the expansion (there is no particular centre, the expansion is uniform about every point in the universe), the universe does not have a "perfect frame". The universe isnt just sitting there so it doesnt make sense to give it one particular frame of refrence.
lfo98 4 weeks ago in playlist Physics
@lfo98 - I disagree. There must be some velocity at which clocks move at their fastest. I guess there is no reason to prefer that frame of reference over others, but it would seem to be the most unique frame of reference. The only other "special" frame of reference would be the one achieved by moving at the speed of light, but since only light can do that, it seem a bit unattainable.
Faladrin 3 weeks ago
@Faladrin What do you mean by velocity at which clocks run fastest? Do you mean take the average of all clock speeds within the universe?
lfo98 3 weeks ago in playlist Physics
@lfo98 - time progresses slower the faster you move. Likewise, the slower you are moving the faster times progresses. So, if you were absolutely still clocks would move at their fastest rate. Relativity gives us the tool to find the frame of reference which truly is not moving.
Again, I'm not sure there is any real reason to prefer the frame of reference of absolute stillness, but it is a somewhat unique frame of reference.
Faladrin 3 weeks ago
@lfo98 - Lets do a thought experiment. You have three clocks all right next to each other, essentially at the same point in space. The three clocks take up some acceleration and de-acceleration such that they end up in a line with distance x between the first and second, and second and third (having chosen an arbitrary left and right with the first clock being on the left).
Faladrin 3 weeks ago
@Faladrin Continued..
A person at each clock can measure the distance between themselves and the other two clocks and is able to send a signal giving his own time. Each person at each clock is therefor able to determine how much each clock is out of sync with their local clock.
Can we agree that each person will determine the same time differentials between the three clocks?
If so then can the three people agree as to which clocks moved?
Faladrin 3 weeks ago
@Faladrin - One note, the acceleration and decelleration were all in a single direction. They were not doing loops or anyting and they did not double back on their own path. They moved completely within the line that they ended up in and only in one direction.
Faladrin 3 weeks ago
@lfo98 - Here is a better thought experiment. Set this up just like the Michelson and Morely experiment, but rather than using light we use time. Three people at the equator sits with thee synchronized atomic clocks. One person gets on a plane heading due north such that he will circle the globe and return from the south. Another gets on a plane heading east and will return from the west. Will the two clocks which traveled match (after adjusting for a non-perfect spherical earth)?
Faladrin 3 weeks ago
@Faladrin for the east bound clock. You can tell the two clocks in the planes have "really moved" due to the accelerations invloved in flying a plane round the world. I still don't really know what you mean by perfect reference frame! GR predicts the fastest a clock will ever run is a non accelerating clock in 0 gravitational field.
lfo98 3 weeks ago in playlist Physics
Loved it. I finally understood the significance of the Michelson-Morley experiment (which I had read about nearly 15 years ago)! You have one sincerely grateful fan in India.
oundhakar 1 month ago
@oundhakar Thanks.
ozmoroid 1 month ago
More.
geneticepistomology 2 months ago
Extraordinarily wonderful, pedagogically masterful series. Well done!
Tr3xKuro 2 months ago
Amazing video, ty
Tharoxxx 3 months ago
Excellent video. I look forward to the rest of the series.
SisyphusRedeemed 3 months ago
My brain freaking Fried!!
*Reboot his brain and watch the video again*
Contevent 3 months ago
Thank you for the video. I love science!
syirrus 3 months ago
What an extraordinarily well put together video. Even I can understand this.
r4d3rz 3 months ago
@r4d3rz Glad you enjoyed it.
ozmoroid 3 months ago
NephilimFree doesn't understand this.
TadRaunch 3 months ago
Thanks for explaining this in a way that is neither insulting nor too confusing.
ShinobuHarvester 3 months ago in playlist More videos from ozmoroid
The failure of the Michaelson-Morley experiment is final proof that the Earth does not move and is the centre of the universe.
Try it on the Moon and you'll see that the luminiferous ether does exist.
(lol jk)
SonOfFurzehatt 3 months ago
Next time I get a speeding ticket i will argue that from my frame of reference I was stationary.
bustermk2 7 months ago
@bustermk2 In fact the cop was speeding!
ozmoroid 7 months ago
This has been flagged as spam show
@bustermk2 that'll make a great bar joke when you have physicist friends!
I've got one btw: Heisenberg is speeding on the highway. Cops pull him over and ask him "you know how fast you're going?" he answers "nope, but I know exactly where I am"
NScott45 6 months ago
I feel stupid after watch this ;-(
parsonman05 7 months ago
When I first went through this in school my mind was blown !! I could'nt get my head to accept this !! Watch light from the ground, and from a moving reference and you mesure the same speed !! Man, but as we played with the concept and equations I ended up understanding well how it works, but its definitly a wierd notion to grasp !
Great video !
659851 8 months ago
Superb sir, thank you.
Benjuthula 9 months ago
Very nicely done :)
Kamalthewafi 9 months ago
When I first heard some of this, I asked "What if the light, itself, is doing the oscillating?" Well, what else was I supposed to ask? I was only 6.
RyuDarragh 10 months ago
Excellent stuff Ozmoroid, the Michaelson-Morely experiment's rationale was never so clear to me.
BiggusRobbicus 10 months ago
There was a shortcoming to the Michaelson-Morley experiment. It was limited to three dimensional space.
pocoapoco2 10 months ago
@pocoapoco2 I'm probably going to regret asking the question, but... "limited to 3D space" in detriment to what?
StrikaAmaru 10 months ago
The lake you threw the rock into was not placid, there were wavefronts moving toward the shore (right) before you threw the rock in. Since there was a velocity vector was there before the rock hit the water it makes sense that the wave would not expand symmetrically and would move toward the right since there was already a component of the velocity in that direction.
Valigarmanda1 10 months ago
Very well explained even I got it.;-)
reafdaw01 10 months ago
Very informative and presented in a nice way. Good job :)
banana1337kivi 10 months ago
Yeah, yeah, great fun. I'd like to see you sink your teeth into the double slit experiment. :)
Maxdwolf 10 months ago
Galileo who? Galileo Jones? Galileo Smith?
I really like Isaac's theories, too, or Charles' book. Albert was brilliant, and so was Paul.
Love your vids, ozmoroid! We must have more!
C0nc0rdance 11 months ago
@C0nc0rdance thanks for BLOCKING me from adding comments to your videos!
EssiacHempLaetrile 11 months ago
@EssiacHempLaetrile And it's so good to see you dealing with it so maturely. :)
Maxdwolf 10 months ago
@C0nc0rdance Paul is dead. If you played this video in reverse you would have heard that. ;-)
ozmoroid 11 months ago
@C0nc0rdance Galileo Johnson
samrustan 10 months ago
@C0nc0rdance Galileo GaGa
dumbnetworks 10 months ago
NERRRRRRRRDDDD!!!!
ionz75 11 months ago
Please wait while I pick up my jaw...
There.
Thanks for another sensational video, O.
Wishing they came more often...
amoxtlacatl 11 months ago
Regarding your third example with the ball and the paddle: You say "it's the ball doing the whacking", but why isn't the paddle going faster to the right? Where is the energy going?
javaskin 11 months ago
@javaskin I assume that the paddle is much more massive than the ball. Therefore, it's change in speed is much smaller than that of the ball - small enough to be imperceptible in this vid.
ozmoroid 11 months ago
@javaskin if you throw a baseball at a concrete wall the wall is not going to move let alone move faster, but the ball will still lose alot of energy. the energy can be lost due to friction with the air, and contacting the surface as well. just like how wood starts to get warm if you smash it a couple times with a hammer.
ItsNotEvenSunny 10 months ago
@ItsNotEvenSunny Most of the energy is lost in the sound made when it hits the wall.
every116 7 months ago
@every116 No, (most) of the energy is just transferred to the wall
ItsNotEvenSunny 7 months ago
i love how einstein calls gallileo "bro."
govcolin 11 months ago
Ozmoroid it's been too long. Great vid!
dgeypscun 11 months ago
6:35 Why does everybody hate on incandescent bulbs? T-T I like incandescent bulbs...
StrikaAmaru 11 months ago
Very nice, I loved it!
oggztah 11 months ago
Mind, blown.
CharBroiled04 11 months ago
I watch science videas to pretend I'm smart, but I have real trouble picturing relativity. This is a good video.
piopob 11 months ago
Modern physics is so counter intuitive that if you tell a lay man that it is possible to create the universe out of nothing due to Heisenberg Uncertainty Principal, they think your Bull$#*!ing them. But the miraculous quran has told us about the uncertainty principal 1400 years ago along with The Big Crunch and also The Ever Expanding Universe at the same time ;)
muzammilali007 11 months ago
This is much better than Islamic bullshit :)
TheRationalizer 11 months ago
@TheRationalizer Relativity is all described in the Qur'an, in great detail. ;-)
ozmoroid 11 months ago
@ozmoroid
Yeah, it's relatively clear, relatively accurate, and whether or not is was written by god is relative to whom is reading it :)
TheRationalizer 11 months ago
@ozmoroid Yeah in such great detail that is why it took 1600 years and non muslims to come up with QED. Then muslims try to say oh it is right here in the quran. LOL
Rotorzilla 8 months ago
Absolutely brilliant, I'll admit that as someone with little background in physics I had to watch the initial latin v greek section twice to make sure I was getting it but that just made learning a new concept all the more satisfying, thank you Oz.
notinmyname2050 11 months ago
Lovely video!
And yay for Ether! Heh.
Hyardacil 11 months ago
Excellent video, clearly explained! I plan to cover relativity in one of my future astronomy series videos, but I doubt I could explain it so well... I'm looking forward to your next one!
finlarg 11 months ago
I love these types of videos...Science rocks.
vargulf19 11 months ago
I can't believe it! One day ago I told you to stop commenting on Desertphile's video and to get to work making one of your own because it's been way too long. I log in today and what do I see? Yippee!!!
Hmm, it's made me wonder if this is just coincidence or perhaps I've been imbued with unearthly psychic powers of persuasion.... Ozmoroid, send me all of your money within the next 24 hours! Man, I can't wait till tomorrow!!!!!
JesusCockInAllahAss 11 months ago
brain burning 90c but yea i got it sorta. Thank you OZ
NateFosterSR 11 months ago
:-)
Wrath0fKhan 11 months ago
As said in video space in not a thing, plus light is not a wave neither a particle, all present assumption are just to console himself to provide some properties to make calculus.
we need to learn as human being more about that visible stuff.
orgolioitalia1 11 months ago
Relativity is the best way to show that common sense and intuition is useless in science.
Reality is a funny thing :|
VapidZero 11 months ago
Exellent video. A good refresher on relativety for those of us who haven't actually used it much after learning about it in advanced physics classes. Very well explained in an easy (well as easy as relatively can get) manner...
TheStigma 11 months ago
Loved it, I've always been into physics and sometimes wish I had gone into it as a career. Faved and subbed, Great Video
Jason442200 11 months ago
Your text book presentation is exceptional.
Now ask yourself what if the motion of any system is absolute? No interaction can alter the total quantity of motion of the system it can only alter the nature of the motion within the system.
MsWanderer1 11 months ago
This is, by far, one of your best videos yet. I don't think I have ever heard the basics of relativity explained so clearly or succinctly in the past.
I hope you'll continue to make videos like this one :)
Thank you!
D3Phoenix 11 months ago
I love me some science. :]
SUBBED!
Now I need to find some of that Time to go back and watch your other videos.
fegolem 11 months ago
Splendid!
ZenoFerox 11 months ago
Thanks for this video, from a physics geek. We need more physics explanations that everyone can understand. It's weird and counter intuitive at first glance, but not magic.
HarshColby 11 months ago
In physics there is not "right" frame of reference, but with light, there is. If two ships move relative to one another by the speed of light, they can either both be moving half the speed of light, but it may also be that one is stationary, and the other is moving by the speed of light. The other ship would then be having the slower time than the other. It all comes down to who did the acceleration. So to know who is "right", you have to check the history of speed changes.
HKragh 11 months ago
superb description of relativity!
illumined1 11 months ago
@illumined1 i agree
Sciborg09 11 months ago
Great! Yay! More! Thanks!
tintiringa 11 months ago
zomg! I want more!
lhvinny 11 months ago
well hot damn, it's about time you make another video! You and PreMed make this so much more fun than I remember it being hehe.
tattooskin72 11 months ago
You lost me when you began talking Greek, lmao
skywize 11 months ago
Bout damn time! X(
But, very good video! :D
However, now my brain is rushing to fulfill some sense of equilibruim. 8O
Which way is up and where is the least resistant path? :*(
AManOfHope 11 months ago
I followed everything apart from the maths formulae presented by the latin and greeks.
I get that light is always travelling at the same speed relative to all points (in a vacuum) but could someone explain to me in layman's terms how, if that is true, we have red shifted & blue shifted light from stars moving towards or away from us?
oh... wait. Is it frequency of oscillation? Meh... But then, if I move quickly towards the red light, will it turn blue? Is the frequency changing?
oh my head
AnonEyeMouse 11 months ago
@AnonEyeMouse Red-/blueshifting is because of the doppler effect. Simplified explanation: You're standing still, and I'm running away from you, carrying a flashlight, that's always pointing in your direction. A specific light wave, with a certain wavelenght, starts being sent out. Because I'm moving, the other "end" of the wave will be sent out from (ever so slightly) further away from you. The wavelength will therefore have been stretched out, making it "redder".
Martymer81 11 months ago
Comment removed
Martymer81 11 months ago
This has been flagged as spam show
@AnonEyeMouse "But then, if I move quickly towards the red light, will it turn blue?"
Yes. The light will be shifted toward the blue side of the spectrum. That doesn't mean it'll shift so far that the effect can be seen without various measuring gadgets, unless you move *really* fast!
Martymer81 11 months ago
@AnonEyeMouse A topic for the next vid in this series.
ozmoroid 11 months ago
@ozmoroid
Mind-teasing question about Doppler shift:
As you approach a light source, there is a blue shift as frequency gets higher. Or is it?
1) Maybe your reference frame is just slower in time?
2) The relative velocity gives a perspective of higher-energy photons?
3) You are piling over literal wavefronts at a faster pace than the source's frame?
4) Are these all just variations of the same idea? Or something more fundamental?
AntiCitizenX 11 months ago
@ozmoroid
NO! I demand you explain all the physics in one, easy to digest video! NAY ONE 500 CHARACTER COMMENT!!!
;P
Looking forward to it.
AnonEyeMouse 11 months ago
@AnonEyeMouse
Yes, it will go blue if you travel towards it :)
TheRationalizer 11 months ago
@TheRationalizer I thought so, though I could not believe my own conclusion. Colors changing because you're moving towards or away from the source somehow felt wrong, but it had to be right because of the doppler effect. If the doppler effect works for light from the stars, then why wouldn't it work for light from eveyday objects (assuming we could move at the speed of light) but then again I'm no scientist. So if I was moving very fast everything would turn blue and red?
Zaltor2 7 months ago
@Zaltor2
Blue as you look forward, and red as you look backwards, and as you look sideways probably just very blurred :)
TheRationalizer 7 months ago
@Zaltor2 and suppose your fucking fast you'd be invisible because you'd look infrared/ultraviolet for all other people which we can't see :p
MrDpsc 4 months ago
Woohoo! A next video!
DavidMTRutten 11 months ago
I look forward to more vids on this. I've tried before and failed to wrap my brain around it.
theshredator 11 months ago
ozmoroid you turn on my lightbulb
kennethh70 11 months ago
This is the best description I've ever heard, and it makes it easier to understand. In fact, it's simpler than I was let to believe, and I can easily wrap my mind around this.
But I just want to make sure of something. If you are moving very fast away from a light source, then that light would be red-shifted, right? So then, the light that approaches you (who are moving away quickly) would be SLOWER than the speed of light between objects that are not moving relative to each other, right?
Rationalific 11 months ago
@Rationalific The red-shifted light isn't 'slower', it still moves at the same speed, but the waves are stretched out. This is an increase in the wavelength and a decrease in the frequency of the wave, but only from our perspective.
Theophage 11 months ago
@Theophage Thanks a lot for the reply. But I still have questions. I'd really like to get to the bottom of this problem. So, imagine I'm moving away from a light source very quickly, and someone else is moving away from a light source only half as quickly as I am. I know that the light appears stretched (like the sound of a siren with the Doppler Effect) but shouldn't the stretched light seem "faster" to the one moving slower away from it, compared to me, who is moving much faster away?
Rationalific 11 months ago
@Rationalific Nope, not faster or slower. Relativity says that the speed of light is the same for all inertial observers. Since you are moving away from the light source faster than the other guy, you will see the light as red-shifted more than he will, but you'll both measure the speed of that light as the same.
Theophage 11 months ago
@Theophage Thanks for clearing that up. It sort of didn't make much sense, but I guess since time slows down the faster you go, the slower time would make up for what should have been the slower speed of light, thus canceling it out and making it appear to be the same speed of light as always...or that's what I think. If I'm still wrong, feel free to correct me again! Thanks for the responses!
Rationalific 11 months ago
good stuff! very nice reference to refresh your understanding of relativity:)
yoyohowjambo 11 months ago
You may be slow in producing vids, but when you do, it's gold, baby. Gold!
gamutman 11 months ago
Awesome geekness and good to have you back :)
Draugo 11 months ago
Great video!
intubatto 11 months ago
I like the historical approach
TheFeltbegone 11 months ago
excellent video
johncrwarner 11 months ago
really awesome!
666Xeres 11 months ago
loved it - Thanks!
mylkTV 11 months ago
This is, like, just a theory, man.
Parabol0086 11 months ago
Just brilliant, cant wait until the next one!
TheHomelessCripple 11 months ago
excellent video. May I mirror it please?
MrMaverickOne 11 months ago
at about 4:30 ia when ya lost me
keggerous 11 months ago
Ohmygosh one of the coolest videos about relativity ever. I am SO eager for the next episode.
zebruh 11 months ago
Awesome stuff! }|:o)
werecow2003 11 months ago
The Teaching Company (teach12. com) has a pretty good course on relativity, for those who want to spend several hours learning it.
Great job on this effort. I hope you explain the difference between special and general relativity.
WarmWeatherGuy 11 months ago
very excellent sir... i teach high school physics and you just handed me some nice material for tweaking the explanations of this weirdness than I have been using... always useful to have someone else summarize this stuff from a different perspective...
odinsraven1000 11 months ago
This has been flagged as spam show
Very interesting lesson. Thanks Oz!
biffle0764 11 months ago
Another way to prove all of this directly is to just examine Maxwell's equations. Any derivation of the wave equation out of Maxwell's curl equations will be independent of any velocity. PRESTO! You just derived relativity, and you didn't need to bother with any gigantic interferometers.
AntiCitizenX 11 months ago
@FranksVoice I ripped this off from NephilimFree! ;-)
ozmoroid 11 months ago
@ozmoroid "i ripped this off from NephilimFree"
lmaooooo
Sciborg09 11 months ago
@ozmoroid His videos on dating advice are great too.
wearealltubes 11 months ago
@ozmoroid
"I ripped this off from NephilimFree! ;-)"
If you rip knowledge off from Nephy, that must be why he doesn't have any left.
synsei1 11 months ago
Fantastic, I remember when I was tutoring a high school student to earn some textbook money. She asked me "what is a sound `wave`?" It was a simple enough question to answer. Then she asked "what is a light wave?".... Crap...
RaymondCorrigan 11 months ago
@RaymondCorrigan Indeed. Reality is just weird.
ozmoroid 11 months ago
@ozmoroid who needs drugs when you have physics?
Madman1234855 11 months ago
@ozmoroid And yet Reality has acted the exact same way for over 13 billion years, without interruption. Maybe we are the weird ones for not seeing Reality as perfectly normal and steadfast.
beriukay 11 months ago
More please.
stork5100 11 months ago
This video is just fantastic.
biscoito1r 11 months ago
I'm stitting here editing a video to poke fun at William Lane Craig and you're making videos about this shit?!
Dang. Please add some fart jokes or boobs to your next video so I don't feel so inferior.
Danmill23 11 months ago
more please
darkdragonsoul99 11 months ago
I love you, Oz.
(No homo)
nishbrown 11 months ago
love your physics videos there always imaginative creative and fun
scatustherising 11 months ago
Thumbs up!
QuantumDarkness 11 months ago
Great video I'll be sure to spread the word about it.
slicingwater 11 months ago