Photon?

[Farsight]

When did you FEEL or measure your acceleration relative to any star?

When the booster kicked in.

As far as any velocity we have relative to any star, we are part of an inertial system dominated by the earth's gravitational field. Any acceleration you feel is realive to the Earth or at best if you ever made it into space, perhaps our Sun.

Tsk. It's called a gedankenexperiment. It features a lot in relativity.

Come on Farsight, you are confusing what you imagine as a hypothetical situation and reality. I mean Einstein, your hero produced a convincing argument against you current position in 1905, when he introduced special relativity.., and he was really consolidating evidence and theory that predated his insights.

No he didn't. And if there's any doubt that you're moving and the star isn't, just start with two observers in gedanken spaceships. One is on one side of the star, the other is on the other. When they accelerate towards the star, you know that they're the ones who are moving. Because the star isn't moving towards them both. It isn't moving in two directions at once.

 

[OnlyMe]

When the booster kicked in.

Tsk. It's called a gedankenexperiment. It features a lot in relativity.

No he didn't. And if there's any doubt that you're moving and the star isn't, just start with two observers in gedanken spaceships. One is on one side of the star, the other is on the other. When they accelerate towards the star, you know that they're the ones who are moving. Because the star isn't moving towards them both. It isn't moving in two directions at once.

Hypotheticals are not evidence. You state things as facts, provide the proof! You cannot prove that any acceleration you experience (FEEL), is not you just moving to a interial state relative to a distant star. Not by how it FEELS or with an accelerometer anyway.

The fixed stars appear fixed whether you are accellerating or at rest with respect to any specific star. In fact many of the fixed stars, from our FoR are accellerating relative to oneanother.

 

[PhysBang]

No he didn't. And if there's any doubt that you're moving and the star isn't, just start with two observers in gedanken spaceships. One is on one side of the star, the other is on the other. When they accelerate towards the star, you know that they're the ones who are moving. Because the star isn't moving towards them both. It isn't moving in two directions at once.

A star is moving in a infinite number of directions at once, because we can describe it using an infinite number of coordinate systems and without a coordinate system, it can't be said to be moving.

GR is all about how one is free to use any coordinate system. When Farsight denies that, he denies GR>

 

[Farsight]

A star is moving in a infinite number of directions at once...

LOL. No it isn't.

 

[exchemist]

Because of all the people here, my physics knowledge is the best.

.

Arf arf.

 

[paddoboy]

The photon energy is E=hf, where f is frequency. The photon doesn't slow down as it goes through the atmosphere. However the "coordinate" speed of light is lower at a lower elevation, so in a way the photon goes slower as it gets lower.

Yep, that's because it has a longer distance to travel.
But of course the proper speed of light remains constant as always as "c"
Oh, and nice to see you gaining some proper knowledge, with your use of the word coordinate. Maybe you are not a lost cause afterall.

What happens is that you and your clocks go slower when you're lower,

More correctly, what happens is that time slows down. Even with an optical clock that you are so fond of using, it's a matter of travelling longer distances as I pointed out to you yesterday.

so you measure the self-same photon frequency to be higher. It's a bit like what happens if you accelerate towards a photon in free space. You measure it to be blue-shifted, but the photon didn't change a bit. Instead, you did.

Only during the acceleration phase. Otherwise the "no preferred FoR still holds.

Hope that helps.

 

[PhysBang]

LOL. No it isn't.

So, to be clear, you hold that stars have an absolute position and momentum.

 

[brucep]

Farsight,


Actually, there's no way to tell the difference, since there are no preferred reference frames. A technical point, which I'm sure you understand.

He's been making that claim for a couple of years that I know about. In this forum. He believes the Schwarzschild bookkeeper coordinates are preferred. That the speed of light isn't an invariant coordinate independent constant. He thinks the one we derive from the bookkeeper coordinates, the remote bookkeeper coordinate speed of light, is the one true speed of light. Do you ever read any of this stuff? Just curious. Lots of good reason not to.

 

[Farsight]

Arf arf.

Yes it is. And I can refer to Einstein and the evidence to back up what I say. For example, here's Einstein talking about the variable speed of light in 1920:

 

[exchemist]

Yes it is. And I can refer to Einstein and the evidence to back up what I say. For example, here's Einstein talking about the variable speed of light in 1920:

Yeah. But science is not religion, in which there are holy texts. It's empirical.

 

[PhysBang]

Yes it is. And I can refer to Einstein and the evidence to back up what I say. For example, here's Einstein talking about the variable speed of light in 1920:

You are excellent at cherry-picking quotations from Einstein that seem, to the ignorant, to support what you say. However, you are dodging the current issue by retreating to one of the topics you feel safe on. It's a nice attempt at a Gish Gallop.

You hold that stars have an absolute position and momentum. You cannot find a quotation from Einstein that supports that position.

 

[Farsight]

Yeah. But science is not religion, in which there are holy texts.

That's one way to say Einstein was wrong I suppose.

It's empirical.

It sure is. And what's empirical, is that there isn't any time flowing through a clock. A clock features some kind of regular cyclical motion which is counted / accumulated and displayed as "the time". So what else is empirical is this: when the clock goes slower when it's lower it's because that motion goes slower. Even when it's a light clock. You will of course be familiar with the parallel-mirror light clock. It's an idealised clock, but nevertheless it's used extensively in relativity. For example, in the simple inference of time dilation due to relative velocity. That's SR time dilation. For GR time dilation, you arrange one parallel-mirror light clock above the other like so:



See how the lower clock goes slower? It can only do that if the light goes slower. Of course you'll find a way to dismiss that too. And it will probably involve some abuse.

 

[wellwisher]

A relative illusion of the universe, having no center has been created, by ignoring mass (we are unable to measure mass directly). The illusion is created by looking only at motion within space-time. For example, say we are in deep space, and assume no absolute reference. We have two rocket ships in relative motion with velocity V. If we assume relative, we can't tell who is in motion. We can pick either as the base reference and measure Doppler shift.

Say we add mass to the analysis, with ship 1 having mass=M and ship 2 having mass=10M. If we collide these two ships with a head on collision, the collision dynamics are not relative. Each collision scenario (using V) will be different in terms of the rebounding of the two masses. The lighter mass in motion, hitting the heavier stationary mass, will cause the light mass to rebound backwards, transferring it momentum into the forward motion of the heavier. While if the heavier was in motion it will plow through and maintain forward motion as the smaller is also punted forward. It was never relative, in reality.

Say in the above scenario, after the head on collision, we notice the little mass being punted by the larger mass. Now we know the 10M ship had the velocity. But since we originally assumed the motion was relative and we had chosen the 1M, due to being convenient, we now know the total kinetic of the system is 10 times higher than we originally expected.

To verify this we set up another team with experiment 2. For this team, we don't show the collision, but continue to allow them to assume the smaller mass was in motion to do their calculations. This team notices bulk events that need more energy than can be inferred from their choice of the 1M being in motion. But since they can't see through the relative magic trick (never saw the head on collision) they will need to postulate some form of dark energy so they can close the energy balance and maintain the illusion of relative motion.

The team that saw the collision now knows they have 10 more energy, than before. They also see this new observation. To them this is not in volition of their energy balance, since they now have plenty of more energy to account for. They don't need dark energy. What they need are more way to explain all the extra mass/energy.

 

[quantum_wave]

Maybe a few of you can respond to a question I have, and let me say that motion is relative, and there is no absolute space or time that can be detected or quantified. Do I understand correctly that some of you are stating that The General Theory of Relativity (not speaking SR here) is interpreted as saying that there is no way to tell if an object is moving? How stupid is that? As MD (I miss him) would have correctly said, the car moves relative to the road. In that example, would you people be saying that the road might instead be moving and the car sitting still at full throttle? Can there be some reasonableness in how you interpret your observations and explanations?

 

[PhysBang]

That's one way to say Einstein was wrong I suppose.

It sure is. And what's empirical, is that there isn't any time flowing through a clock. A clock features some kind of regular cyclical motion which is counted / accumulated and displayed as "the time". So what else is empirical is this: when the clock goes slower when it's lower it's because that motion goes slower. Even when it's a light clock. You will of course be familiar with the parallel-mirror light clock. It's an idealised clock, but nevertheless it's used extensively in relativity. For example, in the simple inference of time dilation due to relative velocity. That's SR time dilation. For GR time dilation, you arrange one parallel-mirror light clock above the other like so:

View attachment 161

See how the lower clock goes slower? It can only do that if the light goes slower. Of course you'll find a way to dismiss that too. And it will probably involve some abuse.

All one has to do to dismiss that stupid gif is to point out that it's a gif. It is not a pair of physical systems, one of which is undergoing time dilation relative to the other. You have never shown us any argument with serious scientific evidence that the gif is representative of anything, despite years of people asking you for that evidence. And before you shout me down as abb Einstein denier, I will point out that Einstein died well before the creation of CompuServe and the subsequent c creation of gifs.

You continue to insult working scientists and your readers here by treating us all like idiots and offering us the same lies and unsupported claims over and over again.

What would your family think?

 

[wellwisher]

Maybe a few of you can respond to a question I have, and let me say that motion is relative, and there is no absolute space or time that can be detected or quantified. Do I understand correctly that some of you are stating that The General Theory of Relativity (not speaking SR here) is interpreted as saying that there is no way to tell if an object is moving? How stupid is that? As MD (I miss him) would have correctly said, the car moves relative to the road. In that example, would you people be saying that the road might instead be moving and the car sitting still at full throttle? Can there be some reasonableness in how you interpret your observations and explanations?

It comes down to the energy balances not adding up. The moving car and the moving road require two different amounts of energy. Relative motion allows one to pick the reference with the wrong energy balance. We can use an once of gas and get an entire road to move using dark energy.

This relative approach may be better for creating more jobs because it will lead to more opinions and more exceptions therefore more high paid experts to mop up the constant mess. But needs of mercenary science should come last behind the truth of energy conservation.

 

[quantum_wave]

It comes down to the energy balances not adding up. The moving car and the moving road require two different amounts of energy. Relative motion allows one to pick the reference with the wrong energy balance. We can use an once of gas and get an entire road to move using dark energy.

This relative approach may be better for creating more jobs because it will lead to more opinions and more exceptions therefore more high paid experts to mop up the constant mess. But needs of mercenary science should come last behind the truth of energy conservation.

Lol.

 

[PhysBang]

No, there is no difference in energy between the two scenarios. In both, energy is required to move the car relative to the road, but in one scenario, the car is expending energy to stay in the same place.

 

[quantum_wave]

No, there is no difference in energy between the two scenarios. In both, energy is required to move the car relative to the road, but in one scenario, the car is expending energy to stay in the same place.

True, and that is a precise interpretation according to GR. But can't you tell which case fits the surrounding environment, i.e. which is in accord with the generally accepted laws of nature at work around us?

 

[PhysBang]

True, and that is a precise interpretation according to GR. But can't you tell which case fits the surrounding environment, i.e. which is in accord with the generally accepted laws of nature at work around us?

GR is the best theory that fits the way that nature works, according to the collected observations and tests that people have done, at least since the 1600s.

It is often easier for us to use Newtonian mechanics, and we might not lose enough accuracy to make this worth our while. But even there, there is complete relativity according to whether or not the car is moving or the road.

It is usually easier for us to merely assume that the car alone is moving. But ease of use is not evidence for truth. It is far easier for us to assume that the road is moving when we are calculating the orbit of the Earth.