But you can use light to determine your absolute angular velocity! No you can't. There are no absolute velocities. All velocities are a relation to something else and light can't be that something else.
But you can use light to determine your absolute angular velocity! That's why the Laser Ring Gyro works. And that's why Foucault and Michelson were able to use the spinning mirror method.
What result do you get with your laser ring gyro on the equator? It tells you nothing, the point you seem to miss is that the laser ring gyro is a third body that you are referencing from, just like my example of the two men floating in space with a spaceship. If you assume that the spaceship is stationary, then you can determine the velocities and directions of the men with respect to the spaceship. The laser ring gyro is no more fixed than the spaceship.
So can you at least give me one good reason why you won't answer any of my color-coded questions?
I have answered those questions. You can answer those questions yourself if you can figure out what your reference frame is and what you mean by an 'instant' in time? When the light leaves the object or when the light is seen by the observer. You don't seem to understand that when you are looking at something you are seeing into the past.
There is no universal 'now'. Time and distance are variables. You should read up on the Michelson-Morley experiment, they tried to use light to determine the Earths velocity and failed. If you were correct that light can determine absolute angular velocity, Michelson and Morley would have succeeded : )
Said MrJesse:But you can use light to determine your absolute angular velocity!
Replied LeGrande: No you can't. There are no absolute velocities. All velocities are a relation to something else and light can't be that something else.
Are you quibbling over the fact that I said "absolute angular velocity" rather then "absolute angular rate?" If there is no such thing as an absolute angular rate then how do you explain a gyro? Even a simple spinning weight works as a gyro. You know that! You're a pilot after all! Does your
artificial horizon or your
turn rate coordinator or your
Gyro compass/heading indicator not work on the basis of absolute angular rate? Ever heard of
Foucault's pendulum experiment?
What result do you get with your laser ring gyro on the equator? It tells you nothing,
Huh? A laser ring gyro works just fine to measure earth's rotation on the equator just like any other absolute reading gryo -- assuming of course you have the gyro oriented in the correct way to measure the rotation of the earth...! Do you really think that a top like
this wouldn't work on the equator? Are you smoking varius weeds? [grin]
the point you seem to miss is that the laser ring gyro is a third body that you are referencing from, ..... The laser ring gyro is no more fixed than the spaceship.
Then how does the ring laser gyro know that the earth is rotating at about 360 degrees per 24 hours even when buried 10 feet deep? Don't you mean that the light inside the LRG is a third body, not the hardware part of the unit?
And you just got done
saying that "Light is not a third body"!
I don't know if you knew this or not, but if you bury a ring laser gyro (or any good gyro for that matter) in the correct orientation, it will measure the earth's rotation. Now it has no idea where the sun is, or anything else - all it knows is that it's rotating -- and what, I ask you, is it basing its measurement off if not absolute angular velocity of zero?
I have answered those questions.
Yeah, yeah, you keep saying that. And I'm well aware that you've answered many questions that I didn't ask, even if they sounded similar. But if you answered the questions I asked, I sure don't remember it! And I also don't remember you ever providing links and saying to me "Here is where I answered that one."
But in any case, if you have already answered them, then would you please be so kind to answer them now as well? They are simple easy questions with short answers; it won't require a lot of thought or typing on your part. If you already answered them then you have nothing to fear from answering them again! (except of course, if you haven't answered them already, then I can see why you won't answer them now.)
You can answer those questions yourself if you can figure out what your reference frame is and what you mean by an 'instant' in time?
Oh I already answered them for myself -- but I came to the opposite conclusion that I expect you will. And I don't know if you know this, but in science, there are times when a measure can be taken of the angle between two things at an instant in time. For example, 2 cars are traveling the same speed down the road. How far apart are they? 20 feet. That 20 feet measurement is a valid measurement and is still valid even though now "frame of reference" was defined - well, actually, the frame of reference was defined - it was the distance of one car in a frame of reference of the other car - in other words, the distance between them, referenced to each other. And this is the same thing with my question, and this is why it is valid of me to ask you about the apparent displacement of the sun from its actual position - at an instant in time because the question is not one of rate but one of angular difference. And I don't know if you knew this, but it is possible for two things to have an angular difference at an instant in time.
When the light leaves the object or when the light is seen by the observer. You don't seem to understand that when you are looking at something you are seeing into the past.
Of course I understand that -- but you seem to not understand that the light's record of the sun is still true even though the record is 8.3 minutes old, because the sun hasn't moved since the record was made.
There is no universal 'now'. Time and distance are variables.
You're totally missing it! Back to my example of two cars which are both moving at the same rate: If they are moving at the same rate (and direction), then the distance between them will remain constant! so once we know them to be moving at the same rate, it is then valid to ask "What is the difference between them at any instant in time." -- Just like it is valid to ask regarding the 2.1 degrees or the 102 degrees for Pluto or the 180 degrees for the 17 minute day or whatever -- because since the sun moves at the same rate as it appears to move, it is therefore valid to ask about the angular difference at any point in time.
You should read up on the Michelson-Morley experiment, they tried to use light to determine the Earths velocity and failed. If you were correct that light can determine absolute angular velocity, Michelson and Morley would have succeeded : )
But Michelson
did succeed in measuring absolute angular velocity! It was called
the Michelson-Gale-Pearson experiment!
That's what I've been telling you all along! While light may not work to measure absolute linear velocity, it can be used to measure absolute angular velocity - and as a matter of fact is used for just that in laser ring gyros today!
-Jesse