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Why is it a fact that nothing travels faster than light?

Forgive me for asking but I am just curious on how we can be so definitive on nothing traveling as fast as light? Who's to say there is nothing out there that we haven't detected or don't have the capability of measuring that goes faster??

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level 1

Fast and short explanation:

Maxwell's laws. There is a relation between the intensity of the electric and magnetic field, called c, and happens to be the speed of self-propagating coupled magnetic-electric fields. What we call electromagnetic radiation, ie, light. This constant is always the same, independently of the speed of the observer. That means, to be true and reality to be causal, that the speed of time must be relative to every observer. If we make the calculations, the speed of time must be an imaginary number for objects moving faster than c. That means there is no real solution for that objects, so they can not exist.

All of these facts have been proved experimentally many times.

Better explanation: Why Does E=mc2?: (And Why Should We Care?) by Brian Cox and Jeff Forshaw.

level 2
Original Poster1 point · 8 years ago

Thanks I'll look that up. The thing by BC and JF

level 1

It's not so much that nothing travels faster than light, it's that the shape of the universe we live in says a few things. Namely:

  • There's a maximum spatial speed, which is something moving purely through the space dimension(s) and not at all in the time dimension.

  • There's a maximum temporal speed, which is something moving purely in the time dimension and not at all in the space dimensions.

Due to the properties of light, it moves at the maximum speed. So it's not that light defines the max speed and maybe there's something faster. Rather, the shape of space-time results in a max speed and light is at one extreme.

level 2
Original Poster1 point · 8 years ago

Understandable -- so if i get what you're saying -- space limits the speed of light to the fastest it can go in that medium (space).. or something similar!?!

level 3

Yes. It's not that hard to visualize. Take some graph paper and make a point. Then draw a line from the point straight up (+y direction, no change in x). Now draw a line of the same length to the right (+x direction, no change in y). Any line of the same length in between those will describe a 1/4 circle arc, right?

Just pretend that y is time and x is space. Light moves along x only.

Something at rest moves along y only and has "normal" time. As something begins to move in space its time component is then shorter!

This graph paper trick is not accurate, but it gives the idea nicely. For further reading: Einstein-Minkowsi space, Hilbert space. Also, Fernando_x recommended "Why Does E=mc2?" and it's an excellent explanation.

level 4
Original Poster2 points · 8 years ago

Thanks man Ima check this in a little bit.. I just got some Vista Malware 2010 shit and now I can't even access the command line or system restore.. gonna try to reboot into system restore.

level 5

try Spybot S&D

level 6
Original Poster1 point · 8 years ago

thanks i think i got it.. i found a website with removal instructions.. had to open in safe mode for a little then i realized i could overide error messages by right clicking the programs and running as admin (even though im already admin) then I was finally able to open Malwarebytes and did a system scan.. found 1 item, removed it and now everything seems to be working like normal

level 1
[deleted]
3 points · 8 years ago

Actually there are theoretical particles called Tachyons that are said to travel faster than light, and therefore backward in time. Any Tachyon emitted would travel all the way back to the beginning of everything!! That said, it would take a Tachyon infinite energy to slow down to the speed of light, so slower than light travel is not possible for a Tachyon.

level 1
2 points · 8 years ago

It would take an infinite amount of energy to accelerate an object with mass to the speed of light.

level 1
2 points · 8 years ago

It's not that we can't measure anything that went so fast, it's really fundamentally that they CAN'T go so fast.

There are many different levels at which you could answer this question. One is the deep question: why did God make our universe the way it is rather, for example, than making a perfect Newtonian universe with no particles but electrons, protons and neutrons. I can't answer that one for you.

Another is a practical question: "What's to stop me from going faster than c if I try really hard?" That one's easy to answer: if you go sufficiently fast (any appreciable fraction of c) then it gets harder and harder to go faster ("you get heavier").

Alternatively, we could take the emotional approach: "But I really WANT to get there sooner!" I have good news for you: arriving sooner is definitely possible. As soon as various people start going any appreciable fraction of c with respect to each other they start having weird disagreements about elapsed time. From the point of view of everyone else, time slows down for the fellow going really fast. So if you can just go fast ENOUGH (which means really, really close to c) then you can zoom through vast distances (like from one star to another) and only have a small amount of time pass. From your point of view. Unfortunately, if you turn around and head BACK to where you started it'll take hundreds of years to get there.

Or perhaps your question is really, "how do we KNOW this?" The answer there is rather interesting. In science, you can't necessarily just go with what's intuitively obvious, not if the actual world behaves differently. It is intuitively obvious that the earth is flat, the sun moves over it, and heavy objects fall faster than light ones -- but none of these turn out to be true. Similarly, it is intuitively obvious that time passes at the same speed for everyone and distances are the same regardless of who's doing the measuring, but these too turn out to be false.

You see, around 1900 there was an interesting problem. Measurements seemed to show that light went the same speed no matter who measured it, but that didn't make sense: for instance, the Earth is rushing around the sun so light moving WITH the earth should be passing us more slowly and light moving TOWARD the earth should seem to be going faster, relative to us. But the measurements weren't showing that. This rather clever fellow named "Einstein" (you've probably heard of him) came up with a revolutionary idea: he threw out the notion that "time" and "distance" mean the same thing to everyone and worked out a theory which was VERY weird but which hung together. This theory predicted the stuff about things getting heavier as they went faster so they couldn't be sped up past the speed of light (in fact, it predicted that weight and energy are pretty much the same thing). It also predicted some other odd things: like if you split a large atom (or merge some small ones) you'll get out MASSIVE amounts of "atomic" energy. The surprising thing is that thousands of different experiments have shown that this theory is TRUE! They've tried things like putting ENORMOUS amounts of energy into a single atom (particle accelerators) and sure enough, the atom gets heavier so you can't speed it up any faster than c.

All right, I hope that's enough detail to answer your question!

level 2
Original Poster1 point · 8 years ago

Well said!! Deserves more than my upvote!! Thanx!!

level 3
2 points · 8 years ago

I'm glad that physics degree of mine is helping someone! Thanks for posing an interesting question.

level 2

if you go sufficiently fast (any appreciable fraction of c) then it gets harder and harder to go faster ("you get heavier")

This is only the opinion of a slower-moving observer. As the captain of a spaceship, there is nothing different in your mass or your acceleration capability.

Unfortunately, if you turn around and head BACK to where you started it'll take hundreds of years to get there

Not if you travel the same speed. The earth-bound observer may measure 100's (or 1000's, or 10,000's) of years passing, but the traveler will measure a "small amount".

the atom gets heavier so you can't speed it up any faster than c

"heavier" is illusory. Certainly, the mass does not increase. From the nucleus' point of view, the accelerator appears to be slowing in time and your magnetic pushes are getting weaker.

level 3

This is only the opinion of a slower-moving observer. As the captain of a spaceship, there is nothing different in your mass or your acceleration capability.

Right.

The earth-bound observer may measure 100's (or 1000's, or 10,000's) of years passing, but the traveler will measure a "small amount".

True, but the traveler will find that vast amounts of time have passed on earth by the time they get back.

"heavier" is illusory. Certainly, the mass does not increase. From the nucleus' point of view, the accelerator appears to be slowing in time and your magnetic pushes are getting weaker.

Here I disagree. It comes down to the definition of "heavier". From the point of view of the physicist running the particle accelerator, the particle gets more and more resistant to acceleration. That's what I mean when I use the word "heavier".

level 1
[deleted]
2 points · 8 years ago

It isn't necessarily a fact, just an interpretation of relativity. There's actually a term for theoretical particles which travel faster than light, Tacyons. However, they're tricky just to think about.

For example, imagine a tachyon traveling towards you and visible. You would be unable to detect it prior to arrival. After it passes, you would be able to see both the departing particle and a mirror image of the particle approaching you.

level 2
3 points · 8 years ago

A Tacyon walks into the bar and orders a beer, then the bar tender says 'Welcome, what can I get you?'.

level 3
[deleted]
2 points · 8 years ago

and simultaneously says, "Man, you sure downed that thing pretty quick".

level 4
1 point · 8 years ago · edited 8 years ago

Too bad your tachyon is mass-less and quickly decides that it isn't an Irish pub he should be hanging out in, but a Catholic church.

level 1

only space itself is faster than light

level 1
[deleted]
2 points · 8 years ago

The math don't lie, brother man. The numbers are solid.

level 2
Original Poster0 points · 8 years ago

Really?? Are they... REALLY?? haha j/k

level 1

because you touch yourself at night

level 2
Original Poster1 point · 8 years ago

You are correct sir

level 2
Original Poster1 point · 8 years ago

I'm not saying it's wrong but seeing through the ages how scientist have proved theories to be wrong, who is to say that somebody might not disprove Einsteins theory of relativity?

I know its been around for a while but as we see time and time again theories get replaced by new more accurate theories.

Now I don't have the mental capacity to change the way we see the universe but I'm sure someone someday will.

level 3

theories get replaced by new more accurate theories

That's true, but there are more than one way for that to happen. Phlogiston was wrong, wrong, wrong and was thrown out. Newton was oh so close but not quite right and Einstein did him one better.

What's the difference? You can still use Newtonian physics to solve problems, and in many circumstances you'll be so close that it's not worth going further.

If Maxwell, Einstein, et al are "overturned" it will be similar to Newton, describing "extreme" conditions where some underlying behavior is found.

level 4
Original Poster1 point · 8 years ago

good point.. thanks

level 3

Ok then, short answer: It seems to be the way the universe is built. Until and unless someone comes up with a refinement to our understanding. Does that make it a "fact?" Define "fact." It is true as far as we humans--including the smartest humans who have ever lived--know.

level 4
Original Poster1 point · 8 years ago

True True -- just thought I'd try to wrap my head around something that its probably incapable of fully understanding

level 5

No harm in trying to understand. I heartily encourage it. It's just that you won't even come close to understanding from a one or two sentence response on reddit. If the subject interests you, by all means do some extended reading on the subject.

level 6
Original Poster1 point · 8 years ago

Ha yea I know.. I'm always researching items that spark my interest, but I've just started using reddit not too long ago and thought I'd throw it out there.

level 4

It seems to be the way the universe is built

Reddit has no place for your "intelligent design" hocus pocus.

  • sarcasm

level 5

It seems to be the way the universe is.

FTFY. No sarcasm required.

level 1

The only thing faster than the speed of light is Metallica. Duh.

level 2
2 points · 8 years ago

Not true.

A Zephyr flying through the night that has her own universe observed by Madonna is quicker than a ray of light.

level 3

Of course you're right, Slayer is way faster than Metallica. My bad.

level 4

Napalm Death is way faster than slayer.

http://www.youtube.com/watch?v=dws87NR6DpM

level 5

Faster, they may be, but better they are not.

level 1
0 points · 8 years ago

Because I said so young man! Now go to your room.

level 1
0 points · 8 years ago

Because something drags the light down. We just don't know what it is. I could be ether ... but then Einstein would be wrong. And if Einstein is wrong then something could be faster then light.

level 1
[deleted]
-1 points · 8 years ago

shadows can move faster than light!

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