So, how does one interpret Einstein's relativity?

[SaltyNuts]

So, the whole idea is that motion is relative. One thing to another. I get that.

But, let's say you have two identical balls. There is an identical clock attached to each. They are the only thing in the universe. I say that one is moving away from the other at close to the speed of light, the other is stationary. But you can't tell which one is the one moving - from each of their perspectives it looks the same, as if the other one is the one moving.

So, in this situation, how the heck would the clocks on the balls know what speed to run - the one that is moving at close to the speed of light should be ticking much slower than the other one. So which clock clicks slower? Am I the only one that thinks about and pokes holes in these things?!

Thanks.

 

[Red Squirrel]

I'm not sure about Einstein but you can interpret Newton's laws via a science experiment that involves a cliff.

 

[Ken g6]

From the perspective of each ball, the other's clock is running slower. From a practical perspective in the real universe, a good way to differentiate such things is to figure out what accelerated and what didn't.

 

[SaltyNuts]

"From the perspective of each ball, the other's clock is running slower."

Are you saying that's the theory Ken, or that's just your guess? Seems odd to me. So, let's start with that same example, but now all of a sudden throw in *the rest of the universe*. You now can see which ball is doing the moving, which one isn't. So now you can tell one ball is moving at close to the speed of light, and the other is sitting still. So, presumably, under the theory, the clock on the ball that is moving at close to the speed of light should be ticking very slowly. But, keep in mind, NOTHING HAS CHANGED WITH RESPECT TO THEIR STATUS. So in the original example you say each of the other's clock appears to be running slower. But under these revised facts, now one appears to be ticking slower and one faster. Spooookeeeey. That doesn't seem right. And even spookier, how would the balls *know about* the rest of the universe being their, so they can now adjust how fast their time ticks? Hmmmmm, wierd stuff...

Thanks for the thoughtful reply!

 

[Cappuccino]

I'm not sure about Einstein but you can interpret Newton's laws via a science experiment that involves a cliff.

lol

 

[mxnerd]

1st. Just imagine that there is a infinite paper grid underneath the balls, then you can tell which one is moving.

So, yeah, the one that is moving at close to the speed of light should be ticking much slower than the other one.

2nd. Don't think you have the ability to poke holes in Eisenstein's theory.

 

[TheVrolok]

Do you honestly believe you're being novel in any of these threads? Honest question.

 

[SKORPI0]

The ball moving close to the speed of light will have a lot greater mass (almost infinite) than the one stationary.

 

[TheVrolok]

The ball moving close to the speed of light will have a lot greater mass (almost infinite) than the one stationary.

Sorta but not really.

 

[HumblePie]

Einstein's relativity theory is basically showing the relationship between matter, energy, gravity, and time through observable/repeatable phenomenon. Nothing more than that really.

The thing is as something is moving through space, time changes based on velocity, mass, and speed (energy) of the object. The faster something moves, or the bigger it is the slower time becomes for that object.

This is why matter, ie something with real mass, can't go the speed of light through nor energy means. The energy needed would basically be all the energy in the universe, or the mass would go to infinity to do it. Either way it's an asymptote. Einsteins theories are also an attempt to explain why light can reach the speed of light as a photon, versus a classic wave pattern quantum particle which is still has some behavioral patterns for.

Basically just take the first sentence if you don't want to delve further. Otherwise do some more reading if you are really interested in this stuff as you aren't going to get the level of depth of information much beyond what I posted here from an internet forum.

People go through years of course study to understand this stuff and you aren't going to get all the info on a silver platter from a web forum on it.

 

[cbrunny]

There's an episode of voyager where they get trapped in a gravitational pull of a planet that experiences time on a much different scale than the ship. If you're interested in this kind of thing, that's a good place to start.

 

[HumblePie]

There's an episode of voyager where they get trapped in a gravitational pull of a planet that experiences time on a much different scale than the ship. If you're interested in this kind of thing, that's a good place to start.

The movie Interstellar talked about this too. The gravity well of a huge ass and very dense (ie massive) planet experience very acute time dilation.

 

[BxgJ]

SaltyNuts, do you ever even bother reading wikipedia at the very least before posting these threads?

 

[BxgJ]

"From the perspective of each ball, the other's clock is running slower."

Are you saying that's the theory Ken, or that's just your guess? Seems odd to me. So, let's start with that same example, but now all of a sudden throw in *the rest of the universe*. You now can see which ball is doing the moving, which one isn't. So now you can tell one ball is moving at close to the speed of light, and the other is sitting still. So, presumably, under the theory, the clock on the ball that is moving at close to the speed of light should be ticking very slowly. But, keep in mind, NOTHING HAS CHANGED WITH RESPECT TO THEIR STATUS. So in the original example you say each of the other's clock appears to be running slower. But under these revised facts, now one appears to be ticking slower and one faster. Spooookeeeey. That doesn't seem right. And even spookier, how would the balls *know about* the rest of the universe being their, so they can now adjust how fast their time ticks? Hmmmmm, wierd stuff...

Thanks for the thoughtful reply!

With respect to the clocks, every clock ticks at the same rate in it's own frame of reference.

 

[IronWing]

With respect to the clocks, every clock ticks at the same rate in it's own frame of reference.

I keep trying to explain that to my boss but she insists that I'm late.

 

[Cozarkian]

The problem is if the balls and clocks are literally the only thing in the universe, you can't accurately state one is moving and the other is stationary.

To determine that one is stationary, you need a point of reference to something else, like space, but then you have added something to the universe.

 

[IronWing]

The problem is if the balls and clocks are literally the only thing in the universe, you can't accurately state one is moving and the other is stationary.

To determine that one is stationary, you need a point of reference to something else, like space, but then you have added something to the universe.

Einstein speculated that space only exists as a byproduct of the existence of mass. If the two balls are the only things in the universe, would the universe increase in size at the same rate the balls separated from each other?

 

[mxnerd]

GPS won't even work if satellite's clock is not adjusted according to Einstein's special & general relativity theory.

http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html

Because an observer on the ground sees the satellites in motion relative to them, Special Relativity predicts that we should see their clocks ticking more slowly (see the Special Relativity lecture). Special Relativity predicts that the on-board atomic clocks on the satellites should fall behind clocks on the ground by about 7 microseconds per day because of the slower ticking rate due to the time dilation effect of their relative motion [2].

Further, the satellites are in orbits high above the Earth, where the curvature of spacetime due to the Earth's mass is less than it is at the Earth's surface. A prediction of General Relativity is that clocks closer to a massive object will seem to tick more slowly than those located further away (see the Black Holes lecture). As such, when viewed from the surface of the Earth, the clocks on the satellites appear to be ticking faster than identical clocks on the ground. A calculation using General Relativity predicts that the clocks in each GPS satellite should get ahead of ground-based clocks by 45 microseconds per day.

The combination of these two relativitic effects means that the clocks on-board each satellite should tick faster than identical clocks on the ground by about 38 microseconds per day (45-7=38)! This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! The whole system would be utterly worthless for navigation in a very short time.

 

[Darwin333]

It depends on which perspective they are viewed from.

 

[LPCTech]

One clock is moving. Its position is changing.

The other clock is not. Its position remains fixed.

The clocks don't "know" anything.

The clock that is moving near to light speed will increase in mass, because of that increase in mass the clock will tick slower RELATIVE to the motionless clock(and the rest of the universe that isn't moving) whos mass has not been altered.

From the perspective of an observer on the FIXED clock the moving clock's time would be slower. From the perspective of an observer on the moving clock time would seem normal because the observer is subject to the mass increase.

The moving clock has changed in that its mass has increased relative to its speed. The fixed clock has not undergone any changes.

The moving clock is ticking slower and the fixed clock is ticking at the normal rate. IF the observer is anywhere but the moving clock.

The moving clock creates a gravitational field due to its mass that literally slows times passage within the field. Relative to outside the field. The stationary clock creates no field. Time moves at the normal rate.

 

[BxgJ]

I keep trying to explain that to my boss but she insists that I'm late.

That's because the boss sets the rules in your work universe

One clock is moving. Its position is changing.

The other clock is not. Its position remains fixed.

The clocks don't "know" anything.

The clock that is moving near to light speed will increase in mass, because of that increase in mass the clock will tick slower RELATIVE to the motionless clock(and the rest of the universe that isn't moving) whos mass has not been altered.

From the perspective of an observer on the FIXED clock the moving clock's time would be slower. From the perspective of an observer on the moving clock time would seem normal because the observer is subject to the mass increase.

The moving clock has changed in that its mass has increased relative to its speed. The fixed clock has not undergone any changes.

The moving clock is ticking slower and the fixed clock is ticking at the normal rate. IF the observer is anywhere but the moving clock.

The moving clock creates a gravitational field due to its mass that literally slows times passage within the field. Relative to outside the field. The stationary clock creates no field. Time moves at the normal rate.

Here I assume you are referring to relativistic inertial mass, which is different from the rest mass (which is invariant in all frames). Useful link -

https://en.wikipedia.org/wiki/Mass_in_special_relativity

Relevant quote -

In general, for isolated systems and single observers, relativistic mass is conserved (each observer sees it constant over time), but is not invariant (that is, different observers see different values). Invariant mass, however, is both conserved and invariant (all single observers see the same value, which does not change over time).

If that helps, m does not change with v but the total approaches infinity as v approaches c.

 

[HumblePie]

That's because the boss sets the rules in your work universe


Here I assume you are referring to relativistic inertial mass, which is different from the rest mass (which is invariant in all frames). Useful link -

https://en.wikipedia.org/wiki/Mass_in_special_relativity

Relevant quote -

If that helps, m does not change with v but the total approaches infinity as v approaches c.

That's why I said the energy increases to infinity

 

[Fardringle]

I like this "layman's" definition of Relativity:

It is possible to sit with a pretty girl for hours and have it feel like no time at all has passed.

It is also possible to put your hand on a hot stove for only a few seconds and have it feel as if an eternity has passed.

 

[Cozarkian]

Einstein speculated that space only exists as a byproduct of the existence of mass. If the two balls are the only things in the universe,

Then space would also exist as the byproduct of the mass of the balls, which would mean the balls are not actually the only thing in the universe.

would the universe increase in size at the same rate the balls separated from each other?

That seems logically sound. In order for the two masses to increase the distance between them, the amount of byproduct/space would have to increase at the same rate that the distance increases.

 

[BurnItDwn]

trying to compare to non-mass is like trying to divide by zero.