Posted on 02/11/2016 9:40:56 PM PST by Rebelbase
From the site: "One of the most simplest and interesting ways to explain Gravitational Waves"
See video link below.
Gravitational waves really bring me down, man.
Excellent. Excellent. Thanks for posting that...
Great teacher!
That would have been if Brian Austin Green explained it.
The idea behind detecting them relies on something in Einstein’s Relativity theory known as the Lorentz Contraction.
Einstein showed that gravitational effects are equivalent to acceleration effects, both of which are covered in his General Theory of Relativity. His Special Relativity only applied to objects moving at a constant speed and direction.
The theories basically say that a clock in motion will tick out time more slowly relative to a clock at your side. Likewise, a unit of distance in motion pass you will appear shorter than the same unit of distance at your side. The latter is the Lorentz Contraction.
Another way of looking at the LC is to imagine that you are traveling at some high rate of speed towards some destination. You can correctly view this situation as you being motionless and the length of your destination moving toward you. And so that unit of distance, via the LC, will shrink due to your high rate of speed. This of course will be in addition to the shortening due to your physically moving closer to your destination.
However, the LC for a gravitational wave, according to the video you linked to, would be in the order of a tiny fraction of the diameter of an atomic nucleus! Yet somehow they apparently were able to detect this minute disturbance in the fabric of space-time.
They actually would detect the wave in the lab by the shortening of a “measuring stick”. One measuring stick lies parallel to the direction of the wave, the other perpendicular. Only the one parallel will be effected by the passing wave and experience this extremely minor disturbance. They would compare the two ‘measuring sticks’ (units of distance) and find that they were not perfectly identical as they were before and after the wave came through, at least for a very brief instant.
...The two “measuring sticks” are actually two perpendicular tubes with light beams shooting through them and bouncing off mirrors at each end. The beams then meet at the center and combine in such away as to cancel each other out (180 degrees out of phase). Any change at all in the lengths of EITHER tube (measuring stick) will result in the beams NOT perfectly combining at the center and thereby no longer canceling each other out.
Got to meet and talk to him several times a few years back, at Columbia University and elsewhere around New York City.
...
the other story here is the continuing amazing development of lasers
The Michelson-Morley experiments.
Yes, the detection device is basically the same: an interferometer
https://www.youtube.com/results?search_query=michelson+morley+experiment+
Thanks for posting this. Brian Greene is really good at providing understandable explanations of astrophysical concepts.
...actually that connection is deeper than it may first appear, as the MME was designed to detect the “ether”, what they believed at the time to be an absolute (stationary) reference frame, a sort of space “fabric”. Of course they failed to detect it, but instead discovered (18 years! before Einstein’s first relativity theory), that light maintains the same speed regardless of the circumstances. Einstein claimed he hadn’t heard of the MME results prior to formulating his theory, despite the fact that his mentor, Hendrick Lorentz, knew full well about it, and had come up with his Lorentz Contraction and dilation formulas in an effort to explain the puzzling MME results.
Yes, but since gravitational effects are equivalent to acceleration effects it basically works out to the same thing, although I can think at the moment exactly how.
...well, in a typical Einstein ‘thought experiment’ he compared the similarity of gravitational effects to acceleration effects by imaging himself being in a sealed elevator, not being able to know if the elevator was accelerating through space or seated firmly on earth with him simply feeling his weight via earth’s gravity. Assuming the rates were identical, a bathroom scale in the elevator would record the same exact results.
Weeellll, there is another way to explain the results.
The Earth doesn’t rotate, everything rotates around the Earth.
I actually have a very detailed thesis from someone which explains in detail how the experiment can be used to prove the geocentric theorem.
Einstein claimed he hadn’t heard of the MME results prior to formulating his theory, despite the fact that his mentor, Hendrick Lorentz, knew full well about it, and had come up with his Lorentz Contraction and dilation formulas in an effort to explain the puzzling MME results.
...
IIRC, Einstein did say he knew of the Fizeau experiments and stellar aberration, which was all he needed to come up with his idea that there was no ether.
What really set Einstein apart was that he believed particles were real, a forbidden belief in German physics at the time. In fact all three of his great 1905 papers were centered on the idea of particles being real, and extensions of his graduate work. It helped that Einstein had little to lose. He was young and not even a professional physicist.
Most of the work for Special Relativity had already been done. That’s why it’s called a Lorentz Contraction rather than an Einstein Contraction.
Like so many successful people, Einstein was in the right place at the right time with the right idea.
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