DanLanglois wrote:
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Why is that? What is this 'trouble'? You say that the Earth moves, but you mean the Earth moves relative to the sun? So does the moon. Then, relative to each other, neither the Earth nor the moon moves. Do you just toss this stuff out to see if anybody knows the answer, or are you really impressed? I wonder where you pick up these figures, what is 70 km, this is how far the Earth moves in 2 seconds, relative to the sun? It might trip you up to picture the sun as being the thing that is moving, given the Copernican revolution, but these observations are relative. The Earth isn't moving towards or away from the moon at all, and when the earth orbits around the sun, of course the moon is always tagging along at the same distance from the earth. The orbital speed of the Earth around the Sun averages about 30 km/s, which is only slightly off, if you work for her majesty the queen, maybe. That's how you get 70 km in 2 seconds? Maybe I better show my work, I figure that the circumference of the Earth's orbit is 940 million kilometers, so I divide that by the hours in a year to get our orbital speed in kilometers per hour.
But also, perhaps one might emphasize that we are moving with the Sun around the center of our galaxy. And/or, that we are moving with our galaxy as it drifts through intergalactic space. I'm not sure what you make of this, but I'm suspecting that your relationship to astrophysics is not what you think it is. If you shine mirrors about, and try using lasers and reflectors between two boats/trains/airplanes/of course spaceships, apparently you assume that something breaks badly at what, some threshold speed?
I could add, that the laser beam that we are talking about, is 6.5 kilometers wide, and out of 10^17 photons aimed at the reflector, only one will be received back on Earth every few seconds, even under good conditions. 'Conditions' being the relative motion of the Earth and the Moon, the rotation of the Earth, lunar libration, weather, polar motion, propagation delay through Earth's atmosphere, the motion of the observing station due to crustal motion and tides, velocity of light in various parts of air and relativistic effects. Nevertheless, that the universal force of gravity is very stable, is one of the findings of this experiment, or still operating Apollo science experiment.
I'm flabbergasted that you think you've come up with a thought that didn't occur to, say, whoever has been in charge of lunar laser ranging activities, since 1969. People who actually hang out at observatories are not so clever as to have thought of this? I'm also flabbergasted that you bring this up, something that could have found a crack Einstein's great edifice of General relativity, and may yet. But so far, lunar ranging results support Einstein. But, you miss that point. Flabbergasting. Are you, then, in fact, putting ludicrous effort into joking w/us?
-- Updated October 20th, 2013, 7:40 pm to add the following --
(Nested quote removed.)
You have read and reread 'the claim'? That, General Relativity predicted that gravity would influence the passage of time? Have you, then, read the General Theory of Relativity, or more widely in Einstein? You seem skeptical that Einstein meant to predict any such thing, but how did Einstein become mega-famous? He predicted that stars would be measured as being in slightly the wrong coordinates in the sky, and not where expected, if they were observed during an eclipse. How did he manage to come up with this outlandish prediction? His formulas are relating gravity to time, those are the general relativity formulas. You're probably familiar with the Newton gravity formulas, or at least this might look familiar, Force of Gravity is proportional to mass1*mass2/distance2
Or, the force of gravity acting between the earth and any other object, for example, is directly proportional to the mass of the earth, directly proportional to the mass of the object, and inversely proportional to the square of the distance that separates the centers of the earth and the object.
And, alternatively, Force of Gravity = Gmass1*mass2/distance2 And, here, G represents the universal gravitation constant. The units on G are sensible, but may seem rather odd. And, knowing the experimentally determined universal gravitation constant (a constant of proportionality) allows you to calculate the force gravitational attraction in Newtons - the unit of force.
How, then, is Einstein different? I'm not just confident, I know of a certainty, that this has been competently explained to you before, and all the effort that went into the posts was wasted because you only pretend to be interested. But, how is Einstein different. Well, first of all, you get essentially identical predictions as long as the strength of the gravitational field is weak. However, there are several crucial predictions where the two theories diverge. This is if if velocities are comparable to that of light, or gravitational fields are much larger than those encountered on the Earth.
What I specifically want to get to, here, is that Einstein's theory predicts that the direction of light propagation should be changed in a gravitational field. As has been proven right, which is indicated by precise observations, and I'm talking, both about the effect, and its magnitude. And this is that eclipse business. Einstein predicted that light is bent by the gravitational field around the Sun. Why? Because, he had extended the principle that Inertial mass = Gravitational mass
Like this, suppose that the earth, at one instant, is observing a light ray that came from a distant star. But, because of the influence of the gravitational field near the Sun, the light ray was deflected as it passed near the sun. Starlight will have an angular deflection. Observed in 1919. The stars appeared shifted from their true positions. Spacetime must be curved. And, Einstein used mathematics to describe gravitation, not by a force, but by the curvature of spacetime. Then, it is often useful to think in geometrical terms when discussing concepts in relativity. Say that you have a geometrical concept of a 'point'. But, let's add the time dimension, and refer to a fingersnap, shall we say, not merely as a point, but as an 'event'. And now, when we're doing General Relativity, time read off a wristwatch is thought of as Spacetime-length, along a timelike curve. And, the the separation-distance you measure between two events, is going to be, well, you'll need to do a radar measurement. And, you're looking for the average of your clock times, or one-half the sum your clock-times. What if you want, rather, the elapsed-time you measure between two events. Again, do a radar measurement, and you want, in this case, one-half the difference of your clock-time. And, meanwhile, a light-ray is a lightlike geodesic curve. Which is a geometrical concept. And, how fast the other guy seems to be moving, well, this too, is a geometrical concept, it's the spacetime-angle between two lines. Specifically, you would decompose his velocity-vector into a spatial-part and a temporal-part. Divide the spatial-part by the temporal-part.
But I suppose that you've put all the effort that your going to put, into understanding Relativity, I suppose that it will never be for you, anything but a bore and a humiliation. And, probably, for most everybody who reads this. It's a bit technical for a forum thread, but I don't blame myself. Invest in your education in physics. I'd like to introduce you to this, so that you get something out of it, but you still think that you're going to win a debate for your cult-like crackpot leader. And, I suppose that you should never change, because I don't like surprises.
But I do like relativity, I really do, some people do.
What a load of boring inane nonsense.You do not even understand the questions posed.Making a lengthy reply filled with every day information does not impress me.Come back when you have worked out my questions with a reply that really answers my questions.You are under the impression that education is intelligence, wrong.Any fool can relay this nonsense.