Why Can’t Anything Go Faster Than The Speed Of Light?
Einstein once called the speed of light “The Universe’s speed limit”. He claimed that traveling faster than the speed of light would violate the causality principle. For the layman, that means cause and effect. An example of this would be a bullet hitting a target before the trigger was even pulled. Achieving light speed or accelerating beyond it would also violate certain energy conditions. It could even allow for time travel.
So why can’t anything go faster than the speed of light?
Before we can dive into that, we have to know what the speed of light actually is, what it means, and clear up some common misconceptions regarding this “universal speed limit”.
The speed of light, (or the speed of a photon) in a near-perfect vacuum is exactly 186,282 miles per second. We perceive photons (light) traveling at this speed because they are massless, or have no ‘weight’.
Every particle in our universe (including photons) move or ‘swim’ through what scientists call “the Higgs field”. As a result of this interaction, particles acquire their mass. Different particles interact with the Higgs field with different strengths, which is why some particles are heavier (have more mass) than others. Photons move through, but do not interact at all with the Higgs field.
What does that mean?
Since photons (light) doesn’t interact with the Higgs field, it means they aren’t bound by any speed limit. Protons simply move at that exact speed because that is the fundamental nature of our universe. Wondering why light doesn’t travel at a different speed is like wondering why gravity isn’t reversed or what it would be like if our universe only had 2 spatial dimensions instead of 3 (4 if you include time). Those constants were set in place when our universe was created at the moment of the big bang.
Universal Speed Limit
Particles that have mass require energy to accelerate them. The closer to the speed of light you get, the more energy is required to go faster because the particles themselves get more massive in proportion to the increased velocity. That means to accelerate to ‘light speed’ would require infinite energy. Not enough energy exists in the entire universe to propel just a single electron to the speed of light.
From A Photon’s Perspective
Interesting and odd things happen at the speed of light. For instance, if you were a photon, time would have no meaning to you. Everything would appear to be instantaneous.
Imagine you are a happy little photon created by a star in another galaxy 4 billion light years away. From my perspective, it took you exactly 4 billion years to travel from that star till you reached my retina. From your perspective, one instant you were created and then the next, you were destroyed when you reached my eye. You experienced no passage of time. Your birth and death happened instantaneously.
This is because time slows for you as your get closer to light speed, and at it, it completely stops. This is also another reason why nothing can go faster than light. It would be like slowing down a car to a stop, and then trying to go slower than completely stopped.
One should think of the speed of light as ‘infinite speed’. A common misconception is thinking the speed of light is just like any other finite speed. The speed of light is only finite from the perspective of the outside observer; from the perspective of a photon, it’s infinite. If you move at exactly the speed of light you could go anywhere, no matter how far, in exactly zero seconds.
Can light be slowed down?
Cherenkov Radiation
There is at least one real world example of superluminal (faster than light) travel. It’s cheating a bit, but it occurs when light passes through water.
Remember, nothing can go faster than 186,282 miles per second, but the photons that normally travel at that speed can be slowed down. An example of this can be seen in water where light is slowed to 3/4th of its normal speed. In nuclear reactors, the charged particles emitted off radioactive rods through the water they are submerged in exceed this reduced speed.
Because the particles contain an electric charge, they emit energy called Cherenkov radiation. Any particles they bump into become radioactive, giving the water an eerie, mysterious blue glow.
So what’s the speed of gravity?
It’s an interesting question that many people may not think about. Does gravity also have a speed and if so, what is it?
Gravity does in fact have a speed. The “speed of gravity” is technically the same as the speed of light. The reason for this is the same reason why light travels at the speed it does. This particular speed is simply a fundamental property of space/time itself. If the Sun were to disappear right this second, the earth would continue its orbit for 8 minutes (the time it takes light to reach Earth from the Sun) before the orbit would be perturbed by the Sun’s absence.
So to sum up, nothing can travel faster than light because the speed of light can be thought of as infinite speed. To match or exceed it would be to go infinity miles per second/hour. There does in fact exist a loop-hole, however. The loop-hole requires a control or warping of the fabric of space/time itself which we’ve touched on in a previous article. (See: “Why aren’t we exploring the galaxy yet?“)
Photos are available under a Creative Commons Attribution license by Wikicommons.
What about Tachyons?
Tachyons are only theoretical particles. With that in mind, they never existed at speeds less than the speed of light, so break no rules. Their existence is somewhat reversed of light speed. They travel faster than light but they could never go slower than light speed.
Correct. If they exist, it would take an infinite amount of energy for them to go light speed or slower. They would bound by the same laws.
Tachyons are unfundemental, also meaning they do not exist… Most likely, I was just reading an artical about neutrinos being speed up to a tiny fraction faster than light! If it is true than E does not equal MC squared, atleast not in man made nature
All transparent media have an “index of refraction”(see Source – Wikipedia.), an internal speed of light, which produces the ‘bend’ (refraction) of wave-fronts. “Cherenkov Radiation”, badly described as ‘Any particles they bump into become radioactive, giving the water an eerie glow.’ should read “light speed particles slow on interacting with the medium releasing that energy as a glow (photons)”.
Boson: “man-made nature”?
TheStalkingHead: Gruff is right (see Source – Wikipedia). Contrary to common experience, speeds are not added, they are only “relative” to C (of E=mc^^2), (no matter who views it) so the “+5″ just takes you a tiny percentage closer to C.
Kotsybar: (nice!: slim limerick 88669 AABBA)
A very old lady quite bright
and trav’ling at the speed of light,
said, “I am never late
but I worry my weight
goes to infinite though I’m quite slight.”
See the ‘Brain of Brian’ ‘Santa-cookie conundrum’ ;)
Tachyons are hypothetical particles they don’t actually exist, there was an experiment conducted which stated that neutrinos are faster or as fast as the speed of light but that is not actually true, there was a problem with the fibre optics and the atomic clock.
OFF THE SCALE
— James Ph. Kotsybar
The young lady known only as Bright,
who could travel at speeds fast as light,
said. “Though I’m seldom late,
I’m concerned that my weight
goes to infinite mass, though I’m sleight.”
1).In water sound waves travels faster than light waves.
2).What about blackholes, since light is unable to escape a blackhole. I’m not sure if there’s some sort of speed involved from the pull of the blackhole like you mentioned about gravity.
Wrong! Things can and have gone faster then the speed of light. There was a recent particle that went faster. I guess we can time travel now.
what if i was in a space ship moving at the speed of light, and then i ran towards the front of the ship at 5 miles an hour? or would my blood stop moving in any direction apart from backwards (spaceship orientation)?
Einstein’s theory says you cannot move at the speed of light, so let’s say your spaceship was moving at 1 mph less than c (the speed of light). Inside the ship, you observe yourself running forward at 5 mph. An observer outside the ship would see that time had slowed down greatly for everything inside the ship – for example, the watch on your wrist would be be ticking incredibly slowly. And you would be running in slow motion, maybe only doing 0.1mph relative to the spaceship. So, you speed relative to the outside observer would be 0.9 mph less than c.
Impossible, your spaceship would disintegrate. Nothing can push your spaceship fast enough close to the speed of light, except maybe a hyper-nova which would destroy even the atoms in your spaceship. lol
You cannot move at all in your ship if its moving at light speed. Imagine you’re standing on top of a moving train. The wind is trying to push you and your train backwards and trying to slow you both down independently. Now you would find it extremely difficult to move forward because of the wind pushing you back and you would require a lot of energy. Same is the scenario with your space ship. The “HIGGS Field” is a retardation to both you and your ship independently. Your ship is somehow getting the infinite energy required to move at light speed but what about you? Your legs wont give you the infinite energy required lol!!
Unfortunatley, this is one area where it is not as clear cut as Einstein makes it out to be. He never actually proves the light speed constant, only declares to go faster would violate a causality principle, which in turn implies time itself also moves at the speed of light. I doubt time is constrained at all.
Now the so called proof of cesium clocks and etc moving fast around the planet in a plane or satellite only proves the mechanical or chemical mechanisms keeping time are affected by gravity and speed in different ways. A clock is not a measure of time. Not like a thermometer measures the actual thermal radiation of an object. Clocks to not measure some sort of time radiation, they are just mechanical or chemical actions that occur in predictable increments of time but are not time itself.
There is in fact no proof at all that time could be traveled, which would violate the causality principle as well, lol. Now this is not to say that we could get a particle to move at the speed of light or faster. BUT is there some unknown type of particle that could? Photons may not be the only things able to bypass the higgs field. Also, space is not constrained by speed either. Collapsing space between two points faster than light travels would be traveling between two points faster than light, relative to the observer. So traveling faster than light with currently known particles in a higgs field is likely impossible due to the energy needed for acceleration but to claim that light speed is the fastest possible speed is not proven this is assumed. Einstein was right about most everything but we must question a part of his theory where he dismisses faster than light speed over a causality principle, then turns around and predicts the nonsense about time travel, which would definitely break a causality principle.
what heppen when we less mass of some object.. It may be go faster then light or not in non gravity area ?
They found a subatomic particle that can go faster than the speed of light. So that like changes our idea of physics. makes me wonder if even bigger objects like other beings or planets can live of move faster than the speed of light.
so if the speed that light travels at is infinite, why can nothing go past the speed of 186,282 miles per second?
They just explained why up the top, read it through a few more times and you might get it. :)
if light takes 8 minutes to get here from the sun, how can you say that from the photon’s perspective if is created by a distant star 4 billion light years away and then destroyed by my retina in a split second?
That’s relativity in action. The 8-minute wait you observe is from a human perspective. Likewise, if we were to patiently wait 4 billion years for that photon to reach us, it would take all 4 billion years as far as we humans were concerned. However, time does not go at the same speed for everyone. From the photon’s perspective, it is instantaneous.
thank you. I understand it. You’re right.from the photon point of view there is no time to pass. So it feels everything is instantaneous.
So in other words, a photon doesn’t exist until it is seen by a human eye (or human machinery)?
It always amazes me how people complicate and fail to understand why it’s impossible to exceed the speed of light. The reason is really incredibly simple. Light is the speed of energy, so no matter how much energy you use you can’t push something faster. Going faster than light is like trying to pull your self up with your shoe laces.
You’re right. If it’s possible to go faster than light then light itself would have gone that speed. Light travels at the speed of light because it’s the limit.
Then how is the universe expanding faster than the speed of light?
I don’t know where you get your information but the universe is not expanding faster than light. If it were you would not be able to see or detect it. How would you be able to see it when light is what you must see it with?
The thing is, light rarely travels at the speed of light if you think about it. If you measure light moving in 2 opposite vectors from our perspective they appear to have the same speed, namely, c. If you think about it from the perspective that we, ourselves, are moving, then one of those lights is moving faster than c and the other is moving slower because you must add or subtract the speed that we ourselves are moving at as the origin of the light. The only situation in which light coming from a flashlight which you hold moves at the speed of light would be if you shone it perfectly perpendicular to your line of movement through the universe.
We will not/cannot travel to other planets. The distances are so great and our limits on speed so limited that space travel is limited to our solar system. If we could ever detect a planet, the odds are that the planet would be unable to sustain life of any kind. Theories of other planets are based on what logic?? We have had radio telescopes for years and any alien life would have found us by now or we would have detected some evidence of some kind. We are alone. God has made us unique and allowed our location to be ideal!
In your article on the ‘Big Bang” you state that at that time all matter within traveled faster than what you say can’t happen in this article….and then slowed down…..confusing………..
Matter can’t travel faster than light, but spacetime itself has no such restriction. At the moment of the big bang, spacetime expanded faster than light.
So, light has no mass. Yet light exhibits a number of characteristics of having mass.
Light has momentum. Are there other examples of momentum without mass?
At what point are physicists starting to play word games? If it smells like a rose and looks like a rose?
Well it was once fact that we would never break the speed of sound so like all other obstacles this too will be overcome someday if we don’t blow ourselves up first. How can anyone say it can’t happen? We have not mastered the universe and how it truly works yet. Perhaps folding space lol. How well do we really understand quantum physics.
I’m just a geek with a little too much time on my hands, but some things are like an aching tooth, and I have to check them every once in a while. This is one of those things.
I was told “Nothing can travel faster than the speed of light”. Okay, lets go with that. So, if nothing can travel the speed of light because the energy required to push something that fast is infinite, and because the mass of anything pushed to the speed of light becomes infinite, why can light travel the speed of light?
Light travels the speed of light because it has no mass. The same with gravity, and who knows what else?
These things have no mass because they are not influenced by the Higgs field. Okay. Why not?
Just about everything else that has mass, therefore, is influenced by the Higgs field. Why not photons, a thing, something that exists?
Everything is made of something. As you break things apart, you find out what makes them. Think super collider. Clothes are made of thread, thread is made of cotton, cotton is made of atoms, atoms are made of pn and e. Protons are made of quarks…..light is made of….?
I don’t get it. It does not make sense.
I understand the concept of traveling at relativistic speeds. I understand that your perspective and an observers perspective are different, but to state that in the reference of light, space travel is instantaneous?
Even energy takes time to go from one point to another. As you elongate the distance, the time to travel it is longer, no matter what your speed is.
You cannot be in two places at once, no matter how fast you travel. To suppose that light exists everywhere at once makes no sense.
Why would something move if it had no mass? What would affect something that has no mass? Not even the thing that gives things mass, the proposed Higgs Boson, can give light mass, and yet light moves?
Thought goes faster than any matter particles. In less than a second I can place my mind/thought on any planet, any solar system.
The reason why faster then light travel is not possable right now, and the fact that we cannot detect objects moving faster then the speed of light is…….. easy answere ALL of our technology is based at or slower then the speed of light. Its like asking a microphone to tell you threw your speekers that light exists. Yes you can pick up em fields with a mic, but it cannot tell you that its light. Furthermore even if they could make a sensor that has 0 lag time that sensor is still powered by electricity and electricty moves at the speed of light, slower if its restricted threw a poor conductor. Having said that untell we come up with somthing that either can absorb faster then light particals and conver them into electricity that we can mesure or come up with a energy sorce that isnot electric in nature and the tec that can use that energy, we will never know if objects the size of our sun or sub atomic particals are flying by faster then the speed of light.
Point of emission of photon is same as point of obsorbtion of atom.So it is not travelling. But we percieve time so we perceive light.
You guys should all get together at a particle physics summer camp take some mescaline and discover astral travel! All will be revealed.
I think man is limited my his own cockiness and his ability to accept that he can be wrong. Accepting that the speed of light is as fast as you can go just because you cant imagine a way to achieve a higher speed is in itself one of the reasons that we cant. Hundreds of years ago the Earth was flat. It was a fact to millions of people, in 50 years I think the fact that nothing can travel faster then the speed of light is going to be just like the fact that the earth is flat. Just takes one person to turn fact into fiction.
Is it safe to say that there is more nothingness than “something”? Nothingness being the vacuum of space?
If so, “something” is smaller than nothing.
Amazing. So u look back and see our milkyway galaxy and there is something trying to get from one side to the other side of the galaxy. This would take billions of years to get there, even at light speed, but when it reaches the super massive black hole in the middle of the galaxy (that is pulling massive stars billions mph in orbit) the black hole will actually suck anything including light up faster than light speed.
If light has no mass, why does it get pulled into black holes?
Theoretically, with the proper (MM) mechanical machine (assuming one could construct such a machine- almost certainly impossible) the communication of information could be made to move/travel almost instantaneously. MM could hypothetically be constructed by utilizing an unbreakable, probably straight, and absolutely rigid string/wire/cable transmission line (obviously made of some currently unknown material and/or process). Assume a tangible cable/line lain down from one end of the universe to the other (or for that matter almost any line distance). Functionally made of any device capable of vibrating/moving the full cable back and forth (just for amusement let’s say a cesium atom powered device can do it) the MM could communicate information relative to any distance via the established cable and code. Transmitting information instantaneously to other points would only be limited to MM’s location, length of the wire/cable, the communicating language/code developed and the transmitter and the receiver. MM communication would occur much (infinitely) faster than communication by current devices which utilize the speed of light. Theoretically we have almost instantaneous communication from one edge of the universe to the other.
Laying the communication line(s) would be a centuries-long slow process but once established the information communicated along the line could travel almost instantaneously.