Einstein formulated the Special Theory of Relativity to describe how an object moving near the speed of light undergoes three specific transformations:
1.Length contracts in the direction of travel.
2.Mass increases towards infinity.
3.Time slows down.
Later, he stated that gravity and acceleration were the same thing, and expanded the theory to describe a gravitational field as a mass-distortion of spacetime.
Can Relativity be expanded further?
(I don’t mean supersymmetry/super strings/M-theory)
I have a nagging suspicion that Dark Matter and Dark energy are in fact spacetime distortions which operate on principles different than GR on galactic/intergalactic scales.
I don’t trust my knowledge enough to explain why in detail, but generally physicists reject the idea that dark matter or dark energy can be explained by the rules changing at very large scales.
Einstein’s breakthrough at describing the anomaly of Mercury’s orbit…the precession of perihelion…finally had a physical/mathematical explanation which couldn’t be explained by Newtonian physics.
Things are “different” when you are within the gravity well of a massive object like the Sun.
If the rules change at the stellar scale, why not change again at the Galactic and Cosmologic scales?
Many people have tried very hard to make that work. It never does.
Furthermore, if dark matter doesn’t exist and is just a manifestation of different rules of gravity, that just adds yet another puzzle, because then we’d have to answer the question of why there isn’t any dark matter. The existence of dark matter is what we’d naively expect: Why should all matter interact with electromagnetism, after all?
Now, dark energy, there you have a point. What we know about dark energy can equally well be explained by either a slight tweak in general relativity (the precise form of the tweak is known, and was familiar even to Einstein), or by a weird substance pervading all of space with exotic properties (and the description of those properties is also known). Right now, it’s in vogue to describe it as a substance, but there isn’t really any substantial basis for that, and if you prefer to explain it in terms of the cosmological constant, you’re not wrong.
Things are different inside any gravity well. Relativity is needed to explain multitudes of things on, above, and orbiting Earth. No GPS without relativity, e.g. No Large Hadron Collider either, and the effects are shown on an extremely small scale.
The Large Hadron Collider has nothing whatsoever to do with General Relativity nor with gravity wells. It does have to do with Special Relativity, but I’m not exaggerating when I say that SR is the best-understood and best-supported theory in the history of science.
I didn’t specify either special or general relativity, so your nitpicking lens is fuzzy.
But both are applicable to the two examples I gave.
It turns out that GPS must account for both special relativity and general relativity to deliver position at 1-meter level and time at 100-nanosecond level to its users.
Of course the long-lastingness of near-light-speed particles that helps the LHC get its results depends on special relativity, specifically reference by @EnolaStraight, whose second post I was responding to, not yours. But it took about two seconds to find a cite from CERN saying that they also run experiments to test general relativity.
According to Albert Einstein’s much-tested theory of general relativity, the modern theory of gravity, antimatter and matter should fall to Earth in the same way. But do they, or are there other long-range forces beyond gravity that affect their free fall?
In a paper published today in Nature, the ALPHA collaboration at CERN’s Antimatter Factory shows that, within the precision of their experiment, atoms of antihydrogen – a positron orbiting an antiproton – fall to Earth in the same way as their matter equivalents.