Speed of light:

[jupiviv]

I don't understand why scientists say objects cannot exceed the speed of light, since it is absolutely possible for objects to do so. If the speed of time is finite, then there must be something bigger than it. That's a logical necessity.

I think the reason why it's said that the speed of time cannot be exceeded is because we can only empirically observe objects which travel at less than light speed, since humans measure distances and see objects based on light. If an object with speed greater than or equal to light speed were launched simultaneously with light, then we could not see the object, because the light would not reflect off it. It would always be one step ahead of the light, so we'd never see it. If we use a reference point in relation to us(or 2 reference points) between which we want to observe the object, then the object with greater or equal light speed would pass it before light can fall on it.

Since logic is not dependent on light, it is irrefutable that there can be objects with greater than light speeds, but we can't currently empirically observe them due to limitations of our perception. Imagine if bats could do science, and did the same theorising as the scientists did with light, but using sound instead. They'd conclude that no object can surpass the speed of sound.

I also suspect that phenomena like particles vanishing in the quantum realm, dark matter and black holes have something to do with this.

[Diebert van Rhijn]

I don't understand why scientists say objects cannot exceed the speed of light, since it is absolutely possible for objects to do so. If the speed of time is finite, then there must be something bigger than it.

It doesn't have to be if one defines an object as something that cannot go faster than light because of how space and time are defined (and are causing 'object' to happen). And this is exactly what they have done.

Since logic is not dependent on light, it is irrefutable that there can be objects with greater than light speeds, but we can't currently empirically observe them due to limitations of our perception..

There are experiments, employing logic, which could derive a faster than light speed from experimental data if it occurred. So far no luck. The data might be limited in some ways though because of a limited model of time and space. This is very speculative though since we don't have any viable alternative model right now to do experiments with, to interpret the perceptions with.

[Nick]

As far as I know, the reason scientists say this is because the equations behind the theory of relativity dictate that an object can not (in what we would consider normal motion) travel faster than the speed of light. It really has nothing to do with the idea that we wouldn't be able to see an object moving toward us that was moving faster than the speed of light or anything like that. That analogy with the bat doesn't make any sense at all either.

[Dan Rowden]

For an object other than a wave style particle to approach, let alone exceed the speed of light, it requires an impossible amount of energy.

[Kelly Jones]

Some funny insights from Celia Green:

[Scientists being sane:] .... 'If electrons are different from one another, we cannot observe it. Consequently electrons are identical.'

'If there is a reason why this event happens rather than that, we cannot observe it. Consequently there is no reason.'

.... "To construct a hypothetical three-dimensional world which is finite and unbounded, we will assume that our bug lives with a whole family of bugs in a space which has no physical boundaries or barriers. If we further assume that the bugs are very massive, then none of the bugs will be able to leave the group because the gravitational attraction of the group as a whole on each bug will prevent it. Furthermore, since the gravitational attraction is so strong, light rays will not be able to leave the mass of bugs either.

"Thus, even if a bug looks off in the direction of space beyond the group, his line of sight will curve back towards the group, always producing 'bugs in his eyes', and he will never be able to see beyond the group.

"'Straight ahead' for each bug always will mean towards the centre of the group. The bugs will not be conscious of any physical barrier, though; as far as they know, they will live in a world which is unbounded. Their world is finite, since the size of the group as a whole is finite and the group constitutes their world.5"

— 5. James A. Coleman, Relativity for the Layman, Penguin Books, 1961, p.108.

...

[jupiviv]

I don't understand why scientists say objects cannot exceed the speed of light, since it is absolutely possible for objects to do so. If the speed of time is finite, then there must be something bigger than it.

It doesn't have to be if one defines an object as something that cannot go faster than light because of how space and time are defined (and are causing 'object' to happen). And this is exactly what they have done.

That's what I said. Space is defined according to how we empirically measure distances, and see objects, and that is dependent on light.

There are experiments, employing logic, which could derive a faster than light speed from experimental data if it occurred. So far no luck.

As I showed above, they cannot measure faster than light objects if they are using light to define space.

As far as I know, the reason scientists say this is because the equations behind the theory of relativity dictate that an object can not (in what we would consider normal motion) travel faster than the speed of light. It really has nothing to do with the idea that we wouldn't be able to see an object moving toward us that was moving faster than the speed of light or anything like that.

Again, the "normal motion" is defined using light. You should understand what people say before commenting on it.

That analogy with the bat doesn't make any sense at all either.

The bats possessed of human-like minds will measure distances using sound, so any object that exceed sound speed(like a supersonic jet) will exceed their measurements. To them, space would be defined in terms of sound, so they would say no object could travel faster than sound, since they couldn't empirically measure such objects.

Basically, the modern interpretation that the speed of light is constant in general relativity is a tautology, given that SI units of distance and time are tied together using the speed of light.

For an object other than a wave style particle to approach, let alone exceed the speed of light, it requires an impossible amount of energy.

That's what the bats would say about supersonic jets.

[Anders Schlander]

I know something quicker than the speed of light, whenever I deliberately dont do anything, my inaction impacts galaxies a million light years away in such a way that they are most likely uninfluenced.

My every thought is a product of the infinite, travelling across galaxies at every turn, so there is no real 'law' that says that 'things' cannot travel across galaxies, or 'be' those galaxies, ultimately. Things do begin and end, but they are not really seperate from everything else. Objects cannot be said to travel at light speed, which is a fine emperical model, but it doesn't preclude things being the Infinite in an ultimate sense, having no inherent boundary between all the rest in the universe, and thus, you 'can' say that things really travel across universes in a flash.

[jupiviv]

A very simple eg. of objects travelling greater than light speed - imagine that you're standing in a clear space and the moon is on the horizon. Now start spinning at the rate of 1 revolution/sec. It isn't hard to do this. The moon is 385,000 kms away, so it will rotate round your head at 1.21 million km/sec! This is perfectly valid, since all coordinate systems are equally valid in general relativity, including rotating ones.

[Nick]

Again, the "normal motion" is defined using light.

What would you have us define normal motion relative to...? You spinning around in circles making the moon appear as if it's traveling faster than the speed of light? Call me crazy, but I don't think that would be particularly useful for anything at all.

You should understand what people say before commenting on it.

Oh ok. Thanks for that.

The bats possessed of human-like minds will measure distances using sound, so any object that exceed sound speed(like a supersonic jet) will exceed their measurements. To them, space would be defined in terms of sound, so they would say no object could travel faster than sound, since they couldn't empirically measure such objects.

Bats wouldn't gauge the distance of an object from their self travelling faster than the speed of sound through use of their sonar, but that doesn't mean that if they had the mental capacity and the tools to understand how photons work and how fast they travel that they wouldn't be able to understand how an object can move faster than the speed of sound through mathematical equations like those found in the theory of relativity.

[jupiviv]

What would you have us define normal motion relative to...?

I don't understand the question. If you don't know what motion is, you should look it up in a physics textbook.

You spinning around in circles making the moon appear as if it's traveling faster than the speed of light? Call me crazy, but I don't think that would be particularly useful for anything at all.

Well, it would be useful to prove that faster than light speed is possible, as I clearly stated in the post. You've a remarkable knack for missing the point.

Bats wouldn't gauge the distance of an object from their self travelling faster than the speed of sound through use of their sonar, but that doesn't mean that if they had the mental capacity and the tools to understand how photons work and how fast they travel that they wouldn't be able to understand how an object can move faster than the speed of sound through mathematical equations like those found in the theory of relativity.

OK first off the bats example was bad, because bats do have vision. But fortunately you missed that point. Anyways, the point you made here is the same as the point I made - that we can't understand how faster than light objects work because we do not have tools to understand them empirically. However, we do have logic, which tells us that it is possible, and which would tell the(imaginary, absolutely vision-less) bats the same.

Another example of greater than light speed - if you leave a starting point in a car traveling at half the speed of light, and turn on your headlights, then you will logically compute that the light will be traveling at 1.5 times the speed of light relative to your starting point, regardless of what an observer at the starting point would perceive.

[cousinbasil]

If the speed of time is finite

How do you define the speed of time? People may say "Time passes quickly," which implies some kind of rate, but this is just a subjective notion. As Einstein himself indicated, time flies by much faster when one is in the company of a pretty girl than it does when one is sitting on a hot stove.

There can be no speed of time, since speed, rates,cycles, etc., are all quantities measured against time.

For an object other than a wave style particle to approach, let alone exceed the speed of light, it requires an impossible amount of energy.

In a nutshell.

If a particle has mass, to accelerate it to the speed of light would require infinite (impossible) energy. A photon has zero rest mass.

My statements here are are simply based on the equations of Einstein's Special Relativity.

[vman]

Your post seems to assume that light's status as the universal speed limit is based on the fact that we have seen nothing which is faster than light. In fact, without having seen anything which can travel faster than light it is still possible to deduce logically that nothing can travel faster than light. Using the experimentally proven fact that from all vantage points what ever type of motion one is engaged in (acceleration etc.) The speed of light relative to said vantage point is the same. If you were running on a road at say, 5 km per hour and a car went by at 60 kph relative to the road and you measured its speed then you would measure it to be going 55 kph. Not so with light, therefore light's speed as measured must always be constant since all objects are essentially stationary relative to light. An object going 99.999% the speed of light would probably defy our efforts to measure its speed. But, since the laws of physics don't change at high speeds relative to light it would still be stationary. As for why everything is stationary as compared to light I have theories but they are irrelevant to this discussion. It could have something to do with the amount of energy which would have to applied to a particle to make it go light speed.