It's a flawed analogy =P imagine if there is shark behind you, you can't go back.
I guess if we figure out how to "pull" on the fabric we call space/time rather than "push" into it, what we and almost all matter tend to do, you could go faster than the speed of light since the force of gravity would just be all "I dun care". Of course, I can't even begin to think of how you would do that, then again... all my physics knowledge is self taught!
Yeah, kind of bad analogy. The gravitational force isn't that strong and easy to overcome. In space there in no notable resistance, except maybe hitting an asteroid. Either, it's impossible or we will probably manage it. I can't live with the feeling that one day, Voices of a Distant Star may be a real problem. "Your RSS feed will be updated in approximately 8 years.."
Is anyone in this thread actually qualified enough to be speaking with the authority that you all seem to be?
Not speaking with authority, speaking with limited knowledge that I want to share in the hopes of educating and being educated by the replies. Did you have anything to add to the conversation at all?
I thought this was all textbook stuff. We could, you know.. look something up.
Yeap, wikipedia is pretty good but never trust it 100%. I usually try to go there when I don't know something, since you can generally assume if wikipedia is wrong someone will soon correct you in a reply.
No, only asking a simple and humbling question.
Yeah, sure humbled me... there I was thinking I was giving Hawkings a run, well... a wheel for his money.
Yeap, wikipedia is pretty good but never trust it 100%. I usually try to go there when I don't know something, since you can generally assume if wikipedia is wrong someone will soon correct you in a reply.
I spose you're right. We could do.. that other thing.
@Norvu: Gravity does indeed affect light. It has no mass, but gravity bends space. This is what special relativity says. An accelerated frame is identical to a frame in a gravity field.
I don't know what else I can say to anything here that Joe hasn't already. I'll reiterate for those of us that didn't catch on the first 10 times: As an object approaches the speed of light, it gains mass. As it approaches c, it approaches infinite mass. Thus, by Newton's second law, it would require infinite energy to accelerate at c.
As a bit of an aside, if you measure the speed of light, you always get 3*10^8 m/s. No matter how fast you are going. No matter how strong the gravity field you are in is.
A couple more things: a vacuum is the fastest medium for light. There is nothing that light travels faster in.
If you have a wire to the next star or whatever you can have two scenarios: 1. The wire is stretched to its tensile limit. In this case, any more pull on it will break the wire. 2. The wire has some slack. In this case, any pull you exert on it will propagate down the wire at the speed of sound in that material.
On the "things faster than light" bit: nothing is actually going faster than the speed of light. Imagine you have the most powerful lighthouse in the universe. So powerful you can see it a star away. It spins at a given rate, say once a second. So the spot will "move" through 2Ï€ times the distance from which you can see the lighthouse. If it's a light-year away, the illuminated spot will move 2Ï€ light years every second. This is obviously faster than c, but the spot isn't real in the sense that it's just a point in the beam being intercepted.
No, I know Joe knows far more about this stuff than I do. I'm just throwing things at him so I will know the answers. You know, I'm trying to learn.
My view on Time Dilation and traveling at Relativistic Speeds is as follows:
You are in a spaceship moving away from the Earth. On this ship you have a TV which is picking up broadcasts from Earth for you to watch. The transmission is coming to you at 30 frames per second.
As you accelerate away from the Earth and approach the speed of light the time gap between frames of the broadcast you are watching will begin to increase. Once you pass 1/30th (roughly) the speed of light you will only be receiving 29 frames per second. You will still get all the frames (eventually) but you will be receiving them at a slower rate than if you were sitting still.
Once you hit half of the speed of light you will be watching the broadcast at 15 frames per second and it will be noticeably slowed down. You might get the impression that time is slowing down but it is not. You are simply going so fast that the interval between frames is exaggerated due to distance and speed.
Once you reach the speed of light your TV will be stuck on the last frame received. It will appear that time has stopped but it has not stopped. You are simply moving at the same speed as the broadcast and are forever receiving the same frame.
Once you pass the speed of light you will begin receiving frames you have already seen and the TV will appear to be running backwards because every new frame you receive will be one you have already seen. Continue at this pace long enough and you will eventually be watching TV from before you left the Earth. You have not travelled in time you have simply gone so far out that you are receiving broadcasts from before you left.
I'm not a physicist I'm just an average person. I'm also not a lawyer. I understand that some words have different meanings in legalese and physics.
For example mass to me means physical mass, not rest mass and not mass+energy. I had never heard of rest mass (or any other form of mass other than physical mass) until I started reading up on all of this today. This is why so many of the discussions I get into on here end up going all wrong. I'm working from a different dictionary than some of you are using.
As long as I learn something I'm content.
I do have a question I have not been able to get an answer on. How is a Photon classified as a particle if it has no mass? Shouldn't it be a wave form or radiation and not a particle?
I also can not find anything that explains to me why the speed of light is a barrier or why accelerating to the speed of light (or beyond) would require infinite energy. I don't want to hear "look at the math" because I have looked at the math and every equation I look at has me look at some other equation just to find out what the symbols stand for. Only one or two actually took the time to say what each symbol in the equation stands for.
Why does energy add to your mass as you accelerate towards c? From what I read it does not add to the physical mass of the object (it does not physically get heavier/larger) it just adds for the purpose of the equation. From what I have read the only reason photons can travel at c is because they have no mass. This leads me to believe that any particle with zero mass can go c and if such a particle exists with negative mass it could go faster than c.
@Norvu: Gravity does indeed affect light. It has no mass, but gravity bends space. This is what special relativity says. An accelerated frame is identical to a frame in a gravity field.
I don't know what else I can say to anything here that Joe hasn't already. I'll reiterate for those of us that didn't catch on the first 10 times: As an object approaches the speed of light, it gains mass. As it approaches c, it approaches infinite mass. Thus, by Newton's second law, it would require infinite energy to accelerate at c.
As a bit of an aside, if you measure the speed of light, you always get 3*10^8 m/s. No matter how fast you are going. No matter how strong the gravity field you are in is.
The gaining mass issue through me at first until I found a paper detailing rest mass and the other forms of mass used in the physics of relativity. I thought the gaining of mass meant the object was becoming physically larger, which makes no sense to me. Upon further reading I have come to understand that it is not gaining physical mass but instead the mass used in the equation is mass+energy. Or did I read it all wrong?
Imagine you have the most powerful lighthouse in the universe. So powerful you can see it a star away. It spins at a given rate, say once a second. So the spot will "move" through 2À times the distance from which you can see the lighthouse. If it's a light-year away, the illuminated spot will move 2À light years every second. This is obviously faster than c, but the spot isn't real in the sense that it's just a point in the beam being intercepted.
I cought on to that one right away. As you move the beam left to right the distance between where the beam was and where it is now may make you think the spot was moving faster than c but the beam of light (the photons) are still only moving at c.
If you were able to take a picture of this happeneing from 90 degrees off the light beam would look like a wave form as you move it back and forth. It would also be a long time before that spot moved because the action of moving the spot is still limited by the speed c of the photons heading towards that spot.
Once you reach the speed of light your TV will be stuck on the last frame received. It will appear that time has stopped but it has not stopped. You are simply moving at the same speed as the broadcast and are forever receiving the same frame.
I think here is where you get a little off. If you're cruising along at c, looking at the last frame, you look down at your watch, and it's running normally. But everyone on Earth is frozen.
How is a Photon classified as a particle if it has no mass? Shouldn't it be a wave form or radiation and not a particle?
Light exhibits both wavelike and particle-like properties. Counterintuitive, I know, but we have observed this.
I also can not find anything that explains to me why the speed of light is a barrier or why accelerating to the speed of light (or beyond) would require infinite energy. I don't want to hear "look at the math" because I have looked at the math and every equation I look at has me look at some other equation just to find out what the symbols stand for. Only one or two actually took the time to say what each symbol in the equation stands for.
The Lorentz transformation tells us why:
Gamma is the factor by which your mass increases. V is your velocity. C is the speed of light. So looking at this, as v gets closer to c, that term approaches 1. So the denominator approaches zero. So 1 over the denominator approaches infinity. So you become infinitely massive. By Newton's second law, F = ma. If you have infinite mass, it would require infinite force to accelerate you.
Gamma is the factor by which your mass increases. V is your velocity. C is the speed of light. So looking at this, as v gets closer to c, that term approaches 1. So the denominator approaches zero. So 1 over the denominator approaches infinity. So you become infinitely massive. By Newton's second law, F = ma. If you have infinite mass, it would require infinite force to accelerate you.
What happens when v equals c+1?
Does this also mean that anything traveling beyond the speed of light can never decelerate below c?
You end up with i in the denominator. I don't even know what that means. It's immaterial anyway, because nothing can go that fast. And your second question is ill-posed. Nothing can go that fast to begin with.
Mr. Fox beat me to it but here's the Reader's Digest version. Einstein was familiar with the recent Michelson-Morley experiment. The results of this experiment meant that there was no ether and that c was constant in a vacuum. Einstein was also familiar with the old Galilean Transformations, which work very well for everyday problems. However, he began seeing a conflict. If c was really a constant like the experiment seemed to prove, then if you were in a rocket and you shine a light beam along your path, the beam should propagate forward at 2c.
So one of the two things has to go. Either the experimental result tending to show that c is constant, or the old Galilean Transformations. Einstein chose the experimental results and tried to see if he could find a new set of transformations.
Now, look at the second equation. That's the equation that transforms a time measurement from one frame of reference to another. The v is the velocity of the "moving" frame. As I asked before, what would happen if v is approaches the magnitude of c? We'll have
in the denominator. What does that reduce to? Right. We can't evaluate it. Sometimes we say that this asymptotically approaches infinity. It's not a problem with the "math breaking down". It's an indication that it's impossible to propagate at c, and, as velocities increase, we see a time difference between the reference frames.
Finally, notice how, when v is small, the Lorentz Transformations reduce to the Galilean Transfromations.
You end up with i in the denominator. I don't even know what that means. It's immaterial anyway, because nothing can go that fast. And your second question is ill-posed. Nothing can go that fast to begin with.
Nothing that we have yet discovered.
My point in raising the question of things going faster than c is not to imply that such things exist but to find out how the equation handles such things if they did exist. From what I read today there are some in the scientific community who believe there may be particles that move faster than c. Mostly sci-fi fodder but I would still like to know how the equation deals with things moving faster than c or does it fall apart?
You assume that Lorentz was 100% correct, though. One must question fundamental laws in order to instigate major innovations in science and math.
I'm not assuming at all. They've been verified by experiment. Here's a famous one:
In 1941, a detector placed near the top of Mount Washington (at 6000 feet above sea level) measured about 570 muons per hour coming in. Now these muons are raining down from above, but dying as they fall, so if we move the detector to a lower altitude we expect it to detect fewer muons because a fraction of those that came down past the 6000 foot level will die before they get to a lower altitude detector. Approximating their speed by that of light, they are raining down at 186,300 miles per second, which turns out to be, conveniently, about 1,000 feet per microsecond. Thus they should reach the 4500 foot level 1.5 microseconds after passing the 6000 foot level, so, if half of them die off in 1.5 microseconds, as claimed above, we should only expect to register about 570/2 = 285 per hour with the same detector at this level. Dropping another 1500 feet, to the 3000 foot level, we expect about 280/2 = 140 per hour, at 1500 feet about 70 per hour, and at ground level about 35 per hour. (We have rounded off some figures a bit, but this is reasonably close to the expected value.)
To summarize: given the known rate at which these raining-down unstable muons decay, and given that 570 per hour hit a detector near the top of Mount Washington, we only expect about 35 per hour to survive down to sea level. In fact, when the detector was brought down to sea level, it detected about 400 per hour! How did they survive? The reason they didn't decay is that in their frame of reference, much less time had passed. Their actual speed is about 0.994c, corresponding to a time dilation factor of about 9, so in the 6 microsecond trip from the top of Mount Washington to sea level, their clocks register only 6/9 = 0.67 microseconds. In this period of time, only about one-quarter of them decay. (Emphasis mine)
You end up with i in the denominator. I don't even know what that means. It's immaterial anyway, because nothing can go that fast. And your second question is ill-posed. Nothing can go that fast to begin with.
Nothing that we have yet discovered.
My point in raising the question of things going faster than c is not to imply that such things exist but to find out how the equation handles such things if they did exist. From what I read today there are some in the scientific community who believe there may be particles that move faster than c. Mostly sci-fi fodder but I would still like to know how the equation deals with things moving faster than c or does it fall apart?
Please try to understand: We won't discover anything like that. It's not a matter of not having discovered everything. It's a matter of impossibility. It's impossible for such a particle to exist.
You end up with i in the denominator. I don't even know what that means. It's immaterial anyway, because nothing can go that fast. And your second question is ill-posed. Nothing can go that fast to begin with.
Nothing that we have yet discovered.
My point in raising the question of things going faster than c is not to imply that such things exist but to find out how the equation handles such things if they did exist. From what I read today there are some in the scientific community who believe there may be particles that move faster than c. Mostly sci-fi fodder but I would still like to know how the equation deals with things moving faster than c or does it fall apart?
I'm tempted to disbelieve the scientists who say there are particles that move faster than c, especially without a source, although I'm no theoretical physicist.
But as for the equation- it can not function at speeds higher than c, because at that point you are dealing with these things called imaginary numbers, which you cannot mathematically compute and return real numbers.
You assume that Lorentz was 100% correct, though. One must question fundamental laws in order to instigate major innovations in science and math.
I'm not assuming at all. They've been verified by experiment.
To summarize: given the known rate at which these raining-down unstable muons decay, and given that 570 per hour hit a detector near the top of Mount Washington, we only expect about 35 per hour to survive down to sea level. In fact, when the detector was brought down to sea level, it detected about 400 per hour! How did they survive?The reason they didn't decay is that in their frame of reference, much less time had passed. Their actual speed is about 0.994c, corresponding to a time dilation factor of about 9, so in the 6 microsecond trip from the top of Mount Washington to sea level, their clocks register only 6/9 = 0.67 microseconds. In this period of time, only about one-quarter of them decay.(Emphasis mine)
Source. Again, you make the assumption that it holds true for conditions that cannot be verified by experimentation, and that there are no anomalies which could lead to exceptions, or a slightly varied and more correct method of calculation that could allow faster-than-light travel. I'm not saying there are such anomalies for sure, but Robert Oppenheimer, upon first hearing of the idea of an atomic bomb, proved it mathematically impossible (with a sound and at-the-time correct proof) and then went about his day (Source).
I'm tempted to disbelieve the scientists who say there are particles that move faster than c, especially without a source, although I'm no theoretical physicist.
But as for the equation- itcan notfunction at speeds higher than c, because at that point you are dealing with these things called imaginary numbers, which you cannot mathematically compute and return real numbers.
You can compute imaginary numbers and return real numbers. Example: if x=2i, then x*x=-4. -4 is perfectly real, but you reached it with two completely imaginary numbers.
Again, you make the assumption that it holds true for conditions that cannot be verified by experimentation, and that there are no anomalies which could lead to exceptions, or a slightly varied and more correct method of calculation that could allow faster-than-light travel. I'm not saying there are such anomalies for sure, but Robert Oppenheimer, upon first hearing of the idea of an atomic bomb, proved it mathematically impossible (with a sound and at-the-time correct proof) and then went about his day(Source).
Ok.Then prove him wrong. Show me contradictory evidence.
Comments
I guess if we figure out how to "pull" on the fabric we call space/time rather than "push" into it, what we and almost all matter tend to do, you could go faster than the speed of light since the force of gravity would just be all "I dun care". Of course, I can't even begin to think of how you would do that, then again... all my physics knowledge is self taught!
Either, it's impossible or we will probably manage it. I can't live with the feeling that one day, Voices of a Distant Star may be a real problem. "Your RSS feed will be updated in approximately 8 years.."
We could, you know.. look something up.
I don't know what else I can say to anything here that Joe hasn't already.
I'll reiterate for those of us that didn't catch on the first 10 times:
As an object approaches the speed of light, it gains mass. As it approaches c, it approaches infinite mass. Thus, by Newton's second law, it would require infinite energy to accelerate at c.
As a bit of an aside, if you measure the speed of light, you always get 3*10^8 m/s. No matter how fast you are going. No matter how strong the gravity field you are in is.
If you have a wire to the next star or whatever you can have two scenarios:
1. The wire is stretched to its tensile limit. In this case, any more pull on it will break the wire.
2. The wire has some slack. In this case, any pull you exert on it will propagate down the wire at the speed of sound in that material.
On the "things faster than light" bit: nothing is actually going faster than the speed of light.
Imagine you have the most powerful lighthouse in the universe. So powerful you can see it a star away. It spins at a given rate, say once a second. So the spot will "move" through 2Ï€ times the distance from which you can see the lighthouse. If it's a light-year away, the illuminated spot will move 2Ï€ light years every second. This is obviously faster than c, but the spot isn't real in the sense that it's just a point in the beam being intercepted.
My view on Time Dilation and traveling at Relativistic Speeds is as follows:
You are in a spaceship moving away from the Earth. On this ship you have a TV which is picking up broadcasts from Earth for you to watch. The transmission is coming to you at 30 frames per second.
As you accelerate away from the Earth and approach the speed of light the time gap between frames of the broadcast you are watching will begin to increase. Once you pass 1/30th (roughly) the speed of light you will only be receiving 29 frames per second. You will still get all the frames (eventually) but you will be receiving them at a slower rate than if you were sitting still.
Once you hit half of the speed of light you will be watching the broadcast at 15 frames per second and it will be noticeably slowed down. You might get the impression that time is slowing down but it is not. You are simply going so fast that the interval between frames is exaggerated due to distance and speed.
Once you reach the speed of light your TV will be stuck on the last frame received. It will appear that time has stopped but it has not stopped. You are simply moving at the same speed as the broadcast and are forever receiving the same frame.
Once you pass the speed of light you will begin receiving frames you have already seen and the TV will appear to be running backwards because every new frame you receive will be one you have already seen. Continue at this pace long enough and you will eventually be watching TV from before you left the Earth. You have not travelled in time you have simply gone so far out that you are receiving broadcasts from before you left.
I'm not a physicist I'm just an average person. I'm also not a lawyer. I understand that some words have different meanings in legalese and physics.
For example mass to me means physical mass, not rest mass and not mass+energy. I had never heard of rest mass (or any other form of mass other than physical mass) until I started reading up on all of this today. This is why so many of the discussions I get into on here end up going all wrong. I'm working from a different dictionary than some of you are using.
As long as I learn something I'm content.
I do have a question I have not been able to get an answer on. How is a Photon classified as a particle if it has no mass? Shouldn't it be a wave form or radiation and not a particle?
I also can not find anything that explains to me why the speed of light is a barrier or why accelerating to the speed of light (or beyond) would require infinite energy. I don't want to hear "look at the math" because I have looked at the math and every equation I look at has me look at some other equation just to find out what the symbols stand for. Only one or two actually took the time to say what each symbol in the equation stands for.
Why does energy add to your mass as you accelerate towards c? From what I read it does not add to the physical mass of the object (it does not physically get heavier/larger) it just adds for the purpose of the equation. From what I have read the only reason photons can travel at c is because they have no mass. This leads me to believe that any particle with zero mass can go c and if such a particle exists with negative mass it could go faster than c.
If you were able to take a picture of this happeneing from 90 degrees off the light beam would look like a wave form as you move it back and forth. It would also be a long time before that spot moved because the action of moving the spot is still limited by the speed c of the photons heading towards that spot.
Gamma is the factor by which your mass increases. V is your velocity. C is the speed of light.
So looking at this, as v gets closer to c, that term approaches 1. So the denominator approaches zero. So 1 over the denominator approaches infinity. So you become infinitely massive.
By Newton's second law, F = ma. If you have infinite mass, it would require infinite force to accelerate you.
Does this also mean that anything traveling beyond the speed of light can never decelerate below c?
So one of the two things has to go. Either the experimental result tending to show that c is constant, or the old Galilean Transformations. Einstein chose the experimental results and tried to see if he could find a new set of transformations.
It is beyond the scope of this post, but you can follow the derivation of the Lorentz Transformations if you remember your high school algebra.
Here are the important results for our argument:
Now, look at the second equation. That's the equation that transforms a time measurement from one frame of reference to another. The v is the velocity of the "moving" frame. As I asked before, what would happen if v is approaches the magnitude of c? We'll have
in the denominator. What does that reduce to? Right. We can't evaluate it. Sometimes we say that this asymptotically approaches infinity. It's not a problem with the "math breaking down". It's an indication that it's impossible to propagate at c, and, as velocities increase, we see a time difference between the reference frames.
Finally, notice how, when v is small, the Lorentz Transformations reduce to the Galilean Transfromations.
My point in raising the question of things going faster than c is not to imply that such things exist but to find out how the equation handles such things if they did exist. From what I read today there are some in the scientific community who believe there may be particles that move faster than c. Mostly sci-fi fodder but I would still like to know how the equation deals with things moving faster than c or does it fall apart?
But as for the equation- it can not function at speeds higher than c, because at that point you are dealing with these things called imaginary numbers, which you cannot mathematically compute and return real numbers.
To summarize: given the known rate at which these raining-down unstable muons decay, and given that 570 per hour hit a detector near the top of Mount Washington, we only expect about 35 per hour to survive down to sea level. In fact, when the detector was brought down to sea level, it detected about 400 per hour! How did they survive?The reason they didn't decay is that in their frame of reference, much less time had passed. Their actual speed is about 0.994c, corresponding to a time dilation factor of about 9, so in the 6 microsecond trip from the top of Mount Washington to sea level, their clocks register only 6/9 = 0.67 microseconds. In this period of time, only about one-quarter of them decay.(Emphasis mine)
Source.
Again, you make the assumption that it holds true for conditions that cannot be verified by experimentation, and that there are no anomalies which could lead to exceptions, or a slightly varied and more correct method of calculation that could allow faster-than-light travel. I'm not saying there are such anomalies for sure, but Robert Oppenheimer, upon first hearing of the idea of an atomic bomb, proved it mathematically impossible (with a sound and at-the-time correct proof) and then went about his day (Source). You can compute imaginary numbers and return real numbers. Example: if x=2i, then x*x=-4. -4 is perfectly real, but you reached it with two completely imaginary numbers.