Physicist: It’s a little surprising this hasn’t been a post yet.
In order to move from one place to another always takes a little time, no matter how fast you’re traveling. But “time slows down close to the speed of light”, and indeed at the speed of light no time passes at all. So how can light get from one place to another? The short, unenlightening, somewhat irked answer is: look who’s asking.
Time genuinely doesn’t pass from the “perspective” of a photon but, like everything in relativity, the situation isn’t as simple as photons “being in stasis” until they get where they’re going. Whenever there’s a “time effect” there’s a “distance effect” as well, and in this case we find that infinite time dilation (no time for photons) goes hand in hand with infinite length contraction (there’s no distance to the destination).
At the speed of light there’s no time to cover any distance, but there’s also no distance to cover. Left: regular, sub-light-speed movement. Right: “movement” at light speed.
The name “relativity” (as in “theory of…”) comes from the central tenet of relativity, that time, distance, velocity, even the order of events (sometimes) are relative. This takes a few moments of consideration; but when you say that something’s moving, what you really mean is that it’s moving with respect to you.
Everything has its own “coordinate frame”. Your coordinate frame is how you define where things are. If you’re on a train, plane, rickshaw, or whatever, and you have something on the seat next to you, you’d say that (in your coordinate frame) that object is stationary. In your own coordinate frame you’re never moving at all.
How zen is that?
Everything is stationary from its own perspective. Movement is something other things do. When you describe the movement of those other things it’s always in terms of your notion of space and time coordinates.
The last coordinate to consider is time, which is just whatever your clock reads. One of the very big things that came out of Einstein’s original paper on special relativity is that not only will different perspectives disagree on where things are, and how fast they’re moving, different perspectives will also disagree on what time things happen and even how fast time is passing (following some very fixed rules).
When an object moves past you, you define its velocity by looking at how much of your distance it covers, according to your clock, and this (finally) is the answer to the question. The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon.
One of the terribly clever things about relativity is that we can not only talk about how fast other things are moving through our notion of space, but also “how fast” they’re moving through our notion of time (how fast is their clock ticking compared to mine).
The meditating monk picture is from here.
Is time dilation and distance contraction a real physical effect with respect to the photon , so in reality , to the photon , billions of light years does not exist , so the photon is physically does not move , but to be stationary it must move at speed of light !!!!
I need clarification to understand this paradox.
I’m with you so far. But how does the changing electric and magnetic component of the photon that we’ve all seen in textbook visualizations fit in? Or circular polarization?
If a photon experiences no time and no distance, then experiments with multiple locations, e.g., splitting a single photon and interfering with itself, must somehow be one location. This is where I get boggled.
-QM
Now suppose a pure consciousness was created at the BIG BANG , and since it have no mass it travels at the speed of light , what relativity is saying is : from HIS perspective HE is at every point in the whole history of the universe as HIS time = infinity and HIS travelling distance = zero..!!
IS THIS CORRECT ?
DOES HE IS REALLY FACTUALLY PHYSICALLY IN EVERY PLACE ?
THEN WHAT IS THE MEANING OF HIM TRAVELLING AT C.?
“No photon has ever asked “are we there yet?””
lol!, that just made my day hehehehehheh but seriously…how can a photon say “we”?
Please explain one other aspect of relativity. If I am stable and a photon is moving at the speed of light, then from the photon’s perspective it is stable and I am moving at the speed of light. Yes? No? Hence, time is not passing for me either (since I am moving at the speed of light). In this sense is time a complete illusion?
@QM:
Particles in general can be in multiple locations. The weird properties of light don’t really change that.
@Bob:
Never thought about that. A photon doesn’t have a perspective capable of being used to define speed, since it has no time or distance to work with. You aren’t passing the photon at light speed (from the photon’s “perspective”).
Light does not travel at the speed c when travelling through a denser medium.. say water or glass. Does the same concept hold true then?
Thank you so much for posting my question on the site and giving such a beautiful answer, now you have told me, it does make total sense, reminds me of a layman’s quote from brain cox about relativity “space and time are one, the more you have of one, the less you have of the other” I just hadnt realised that this extended as far as having all time and no distance. Thanks very Much
Dan
There are so many logical and factual aspects that can be used as evidence that time dilation and distance contraction are mere mathematical results not a physical reality , other-wise a massive contradictions would result.
Both time dilation and distance contraction are effects of motion of observers in a world with constant speed of light irrespective of any motions .
Without a moving consciousness no such effects exist in reality.
Are you are saying then, everything appears stationary at C., and we only visualize
movement because either we or some object moves to another plane?
Now explain this :
The muon experiment , is done in north and south poles in the same instant…
According to distance contraction the distances between earth and both muons are contracted from the perspectives of the muons….but this means that the earth is moving north ward and south ward in same time !!!!!
So TD and DC are both illusions in eyes of moving or measuring consciousness.
And this : an atom is moving close to C , it shrank to 1/4 its original diameter in direction of movement , but the atom is almost a void space , so , does its space contract , according to SR it must , is not this an absurdity ?
Then if it moves in a spiral ???
Then what is the physical mechanism ( not mere LT formula ) that shrink space in a direction after direction after direction ….a.d. a.d. , a.d. ………..
Now , during space inflation with speed of light , how could it expand while it is contracted ?
How could we measure red shifted photons arriving now while they cross the whole history of the universe ?
conclusion :
All these are illusions due to movement , not physical real phenomena .
I would be really glad if you show me that the delusion is in the eyes of the writer .
@Kathrick:
There’s a whole post about that!
A photon doesn’t have a perspective capable of defining the speed of anything else, so it’s not that light sees everything else as stationary, so much as it doesn’t really see anything at all.
@aa. sh.:
The example of upper-atmosphere muons is a classic. But the “movement of the Earth” isn’t a length contraction effect it’s a lot more straight forward. If object A sees object B moving left, then B will see A moving right. If the Earth “sees” a particle moving down, then the particle “sees” the Earth moving up. The particles on opposite sides of the Earth disagree about how the Earth is moving, but luckily there’s no law that says they must agree.
Length contraction is difficult to understand (happily, there’s an old post or two to help), but ultimately it’s not about things being squeezed. Length contraction comes from a careful consideration of what it means to measure length. In particular, we define length as the distance between the front and the back of something at a particular instant. Unfortunately, “a particular instant” isn’t something that’s the same to everybody. This is called the “Relativity of simultaneity“.
Thanks , but i meant that with SR the MUON exp. could be explained either by extended half life-time of the MUON or by the distance between the muon and surface of earth contracted , my thought exp. shows opposite distance contraction which is absud.
You did not answer :
Does SPACE inside a moving atom with speed of light vanishes completely ???
Did you notice that speed limit was assumed then an equation was designed to satisfy the assumption , since ( 1/( 1-v^2/c^2) will always give v < c …. not as reality but as assumption.
N. B. :
MUON exp. matched SR because its result calculations used equations that assumes TD.
LOGICAL FACT : you cannot use assumption to prove theory , you must use facts.
Allow me to explain myself :
1- According to SR the MUONS are at rest , the earth is moving towards them , MUONS
come from all directions …….so , earth is moving in all directions ….absurd.
2- During cosmic inflation at speed of light , space inflated/ contracted in the same time , inflation era took infinite time …..absurd.
I am not challenging , i need explanations.
Say I am continuously accelerating in a circle, I don’t think I can still say that I am sitting still and the world around me is moving. Does acceleration fit into special relativity at all or is it wholly in the realm of general relativity?
You can talk about acceleration in special relativity. General relativity crops up when you equate gravitational and inertial acceleration.
aa.sh: The equations weren’t invented to correspond to a suggested speed limit. c cropped up in Maxwell’s equations, which described the behavior of elecromagnetic waves. Einstein later did the work that determined that this was a frame-independent speed and represented a cosmic speed limit.
The equations were derived from real world observations, and lead to the discovery of the speed limit. The speed limit wasn’t assumed and then equations created to match it.
A question, Is the universe cyclical? Dr. Penrose has several views of it happening of which I am unable to understand. What is your view?
After listening to Dr. Penrose propose his theory of a cyclical universe and getting no response, I dug up the following links. Is it possible that dark matter, antimatter or dark-energy could be the precursor of the Big Bang? Since only about 4% of matter in viewable in the universe, where is the rest? Might it be that the core of this universe contains the other 96% as anti-quarks, amassing to become the next Big Bang? Just a thought? The links explain rather descriptive possibilities.
http://www.physicsoftheuniverse.com/topics_bigbang.html
http://www.physicsoftheuniverse.com/topics_bigbang_antimatter.html
A photon has no inertia, so even were it to be slowed to below the “speed of light in a vacuum,” it *still* experiences no time, and the shortest moment (a Planck un-moment?). Do any of the other bosons lack inertia? Would they experience zero time at C?
In my approach to understanding this, remotely I’ve taken the approach that by asserting that experience is fixed, all experience is in fact a moment long. That is, everything is a moment long, irrespective of time spent. Time is an arbitrary measure that only confuses matters. This is also a Zen view (I’m Buddhist, how much that plays a role in my thinking here, dunno…).
I have framed the problem, intuitively, by dispensing with the idea of time as a metric, and look instead at experience of moments (information). Of the material things that *do* experience changes in state (information) they have inertia. Without inertia the information potential of a thing drops to zero.
In a related thought I find it interesting how gravity plays into this, along with the Higgs. The Higgs field imparts mass (and hence, inertia) to those particles which interact with it. According to Relativity, mass imparts gravity, and in turn gravity is a constant acceleration, which in turn causes time dilation (the event horizon of a black hole is said to cause a similar state to being accelerated to C).
But I’m totally winging it here. So… acceleration reduces information density until it reaches zero?
I understand gravity is thought to exist at a level beyond the Higgs, as an even more fundamental force. So I’m guessing that time dilation is an interaction that occurs as a result of interaction between those two, or intervening, fields.
The phenomenological flux from inertia is mutable by token of interaction with the Higgs, whether it be through “weight” or “speed.”
In other words, the flux of phenomena is arbitrated by a change in some form of information density, as though as the level of interaction with the Higgs (or some other) field increases (by token of speed or gravity) it is brought closer to a state of infinite mass and anti-infinite information.
That made no sense.
Thank you for reading.
lee says:
April 30, 2013 at 11:03 pm
A photon has no inertia, so even were it to be slowed to below the “speed of light in a vacuum,” it *still* experiences no time, and the shortest moment (a Planck un-moment?). Do any of the other bosons lack inertia? Would they experience zero time at C?
In my approach to understanding this, remotely I’ve taken the approach that by asserting that experience is fixed, all experience is in fact a moment long. That is, everything is a moment long, irrespective of time spent. Time is an arbitrary measure that only confuses matters. This is also a Zen view (I’m Buddhist, how much that plays a role in my thinking here, dunno…).
5/1/13
Not to be presumptuous, but if time stands still at C, perhaps it is where we get the idea of Instantaneous Transcendental Teleportation?
Perhaps. Although that’s pretty far afield from physics or Buddhist empiricism.
Time is only a metric of change. Past that and we go down a rabbit hole.
lee says:
May 1, 2013 at 10:02 AM. Although that’s pretty far afield from physics or Buddhist empiricism. Time is only a metric of change. Past that and we go down a rabbit hole.
Rigney 5 /1/13 Buddhist empiricism? Not trying to be facetious, but at present aren’t noted scientists working nonstop on the theory and application of “Instantaneous Teleportation”? It may be a tremendous leap forward, and I‘m sure hoping it isn’t jumping into a rabbit hole.
@rigney
There is a technique called “quantum teleportation”, but unfortunately it’s not instantaneous, or even really teleportaion. There’s an older post about it here.
While these articles are a bit fuzzy in explaining Teleportation, it’s nice to know the process is now beyond its sci-fi phase.
Instantaneous teleportation may have come a small step closer
thanks to a team of UK physicists. goo.gl/fb/G002G
http://science.howstuffworks.com/science-vs-myth/everyday-myths/teleportation.htm
While these articles are a bit fuzzy in explaining Teleportation scientifically, it’s nice to know the process is now beyond its sci-fi phase.
Instantaneous teleportation may have come a small step closer thanks to a team of UK physicists.
goo.gl/fb/G002G
http://science.howstuffworks.com/science-vs-myth/everyday-myths/teleportation.htm
So a photon experiences no time, so really its just standing still in the exact place it was created? And its birth is the same “time” as its death so basically it never existed boggling stuff.
“Everything is stationary from its own perspective. Movement is something other things do. When you describe the movement of those other things it’s always in terms of your notion of space and time coordinates.”
Interesting. Would that imply that Zeno was correct and there is no dichotomy paradox? All motion really is an illusion…You never move, everything else in the universe moves around you.
Also, just an observation. It’s interesting to note, in first person computer simulations (i.e. video games), your character never actually moves around. Your point of view from the screen is always the same. The software written for the game moves the environment around the character, giving the illusion of movement. Is it too much of a jump to say that the universe acts the same way?
@Kruse
Relative movement (movement relative to something else) is definitely real, and not an illusion. Relativity just makes the assertion that the statement “I am moving” isn’t worth much unless you can specify something that you’re moving with respect to.
Taking this paradox into consideration I can’t help but wonder how we rationalize movement other than as a natural phenomenon. For instance, a bullet zips toward a target, you don’t see it per se, but you can hear and witness its impact. And television. It’s almost a perfectly moving animation, but it isn’t a physical happening at all. Have you ever watched a rose bloom, or a kitten grow into maturity? What about your wife moving in the dark while asleep in your bed. You can feel her, but you don’t see the movement. Am I missing something here?
Minor word usage gripe: In this phrase “the central tenant of relativity,” the correct word is “tenet.” A tenant is someone who occupies an apartment or other dwelling.
Thanks!
If I could spell, I probably wouldn’t have been forced into physics.
One last question. If a photon doesn’t experience time, then how does it exist?
this was essentially my original question, and i still cant get my head around something existing in 3 spatial dimensions but not existing within a temporal one.
In general, a photon doesn’t have a coordinate frame to describe the universe. That is to say; a photon doesn’t experience time or space. The position of a photon, and the time when it’s at that position, are defined by the coordinate frames (the measures of position and time) determined by other things in the universe.
Then again, doesn’t your last statement apply to everything that exists throughout the universe? To me, relevancy of an object is predicated on the position and speed that it is viewed.
The following statements were taken from the internet.
Quote:
The average distance between the moon’s surface and the earth’s surface is 380,500 kilometers(km). Light is an electromagnetic wave and travels at a speed roughly 3 x 10^8 meters/second(m/s) in a vacuum. Since distance = speed*time the time it takes for the laser pulse to travel from the the earth to the moon is, time = distance/speed. For round trip time = 2*(distance/speed). So the calculation is: time=2*(38500 x 10^3 m / 3 x 10^8 m/s) = 2.56 s.
Radio signals are electromagnetic waves, and as such they travel at the speed of light. c = 3×10^8 m/s, so it would take 1.27 seconds for a signal to reach the moon at a distance of 380,000 km.
The doppler shift works great in an atmosphere. But is it practical for intergalactic space? In a short, If radio waves (i.e) red shift; light rays, truly lengthen over time and distance, will we ever receive a transmitted signal from another galaxy that is intelligible? My reason for asking, has red shift proven to be infallible ?
Maybe this’ll help:
Time is a function of experience. In high-inertia environments, the rate of experience is slowed down – in a logarithmic function of gravity or speed. I’m going to assume you’re familiar with the quandaries about what happens in the “inside” of a black hole, where the rate of experience is slowed to a null state.
What do we know about the mass of particles, the ones with inertia that acquire their mass from their interrelationship with the Higgs field (among other interactions)? They resist moving through the Higgs, they gain more and more inertia as they move.
Photons do not interact with the Higgs, and are in a null experience state. They can interact with Higgs-interacting particles, but how I can’t speculate whether the Higgs arbitrates those interactions (photoelectric-effect). For a Higgs-interacting particle to achieve null experience by token of speed would require travelling in the same field that photons propagate in. It’s not possible, Higgs-interactors can’t become non-Higgs interactors … the energy requirement is hyperbolic to infinity. It’s functionally irrelevant.
However…. Gravity has a similar function to speed on retarding the rate of experience, AND gravity can achieve a state of null-phenomena – null experience – without infinite energy. The problem of increasing mass due to speed doesn’t come into play here, the mass of a black hole is what’s been put into it, it doesn’t actually change, but the gravitational field distortion imparted by mass (originally imparted by the Higgs field) overrides the ability for phenomena to actually experience change. In a sense, the constantly arising flux of the present moment simply ceases to be … it is brought to an immaterial null state.
But then inside a black hole there are no more neutrons or quarks, it’s a soup of field energies that are even more fundamental than the forces that affect photons. Gravity and the shape of space itself are conjoined, so it must be a very fundamental level of interaction. In a sense, black holes are miniature nodes where space regresses to the singularity state before the big bang. It’s fundamental to the physical universe that space itself can flex as its material phenomena become ultra-compacted from their own interactions with the gravity. They are lost to “normal” space and enter into a primordial field-state that actually abides all space.
So conceptually, particle can actually achieve via gravity the same state of null experience as a photon (in a black hole). It’s a finite amount of gravitational intensity to render this null experience, and to eliminate the experience of causality.
Outside the a-causal state of a black hole – in the “karmic” universe of normal space – causality continues. Paradoxically a black hole can cause events outside its a-causal internal reference frame, but only where gravitational infinities don’t arise, beyond its event horizon. So a reference frame that is outside cause & effect still interacts with other reference frames bound to cause & effect.
Photons can also interact w/ causal space-time, and likewise have zero information inside them, null experience. They affect other arising phenomena outside their frame of reference by interacting as particles, not as waves. In their wave state, there is zero time, no cause & effect, null experience. But in their particle state, the information is instantaneously conserved via field interactions.
That’s the narrative as I can describe it.
It’s as though we had different types of fluids of varying viscosities in a tub, where a variety of ultrasonic wavelengths are driven into the medium & help characterize the net viscosity of the fluids, kinda like a jello bath. Or a giant lava lamp where the wax blobs are made of different things, and they form as a result of sono-additive standing waves in the medium… Jello, lava wax … the knots of jello form where certain additive ultrasonic interactions occur early on in the making of the jello bath. Meanwhile waves can propagate through this “aether” & can effect the knots of jello where they interact… the wave going through the bath aren’t in any jello state, so they don’t experience jello-ness ….
Space & gravity are so completely fundamental to the functioning of the physical universe that it – along with other fields that exist beyond the quantum vacuum – basically sets the ground rules for how each type of phenomenological knot of information interacts with other knots, experiences information, and so on.
It’s as though the rules make up a recipe. The recipe for our psychedelic jello bath is very fine-tuned to make a working psychedelic jello bath. Without the energy, the rules (that govern how the jello knots form from interacting ultrasonic frequencies) are nothing. And without the rules, the energy wouldn’t form jello knots & make our jello bath interesting. Together they make a recipe…..
So why in all documentary programs scientist say that it will take a billion of years traveling at the speed of light to get to another galaxy for example while from the point of view of the person traveling near the speed of light it will take …… drums …..near zero time?
From the point of view of a person here on earth it will take billions of years but i think point of view of the person traveling is VERY IMPORTANT TOO.
If time is relative, distance is relative.
Remember the twin paradox? When you send your twin on a journey with a speed near the speed of light he will age less then you here on earth. But many forget that he will also travel a grate amount of distance and wont age!!! So why bother with hibernation, warp speed bla bla bla. If you manage to travel near that magical c every corner of universe is a moment away!!!
@Łukasz
If you are somehow on a spaceship traveling near the speed of light, time for you would feel normal. A minute would feel like a minute etc. So say this space ship traveled for 50 years at near the speed of light, you and everyone inside would age 50 years. Now, say you somehow flew back to Earth and that took another 50 years. You would have aged and experienced 100 years.
But for someone who stayed on Earth the whole time, they would have experienced (don’t know exactly) 10000 years because time on the spaceship(time relative to the people on earth) moved slower than Earth time. I don’t think the people on the spaceship would be moving in slow motion from their own point of view.
That is why it is the theory of relativity, the time that passed is relative to where you are. Time does not flow at the same rate throughout the universe… although a human would not think in slow motion, it would feel like normal to a person in an exact spot.
Time is a measure of changing relationships in matter and energy, the measurer is not outside the system being measured. To make a meaningful measurement one must have a comparison standard which must be a stable cycling event that can be counted. This standard of measure is also part of the entire system being measured. As seen in this light, no pun intended, time travel paradoxes should vanish as the movement of a mass to any spacetime co-ordinate never implies the rest of the universe would be effected in a similar way… ie, if I move my mass to what is considered a past spacetime co-ordinate, the rest of the mass of the universe does not move with me and so I do not find “the past” but rather I likely find empty hyperspace or I find myself down a four-dimensional hole.
As humans we have given “time” a bad time. To us it is only relevant to the here and now or what we project it to be, but to the entropic movement of nature, time is totally irrelevant. At this very moment, even though the distance be 10 billion light years, if there are living creatures at that place, this very second of time belongs equally to each of us.