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How Einstein Lost His Bearings, and With Them, General Relativity (quantamagazine.org)

Kevin Hartnett, writing for Quanta magazine: Albert Einstein released his general theory of relativity at the end of 1915. He should have finished it two years earlier. When scholars look at his notebooks from the period, they see the completed equations, minus just a detail or two. "That really should have been the final theory," said John Norton, an Einstein expert and a historian of science at the University of Pittsburgh. But Einstein made a critical last-second error that set him on an odyssey of doubt and discovery -- one that nearly cost him his greatest scientific achievement. The consequences of his decision continue to reverberate in math and physics today.

Here's the error. General relativity was meant to supplant Newtonian gravity. This meant it had to explain all the same physical phenomena Newton's equations could, plus other phenomena that Newton's equations couldn't. Yet in mid-1913, Einstein convinced himself, incorrectly, that his new theory couldn't account for scenarios where the force of gravity was weak -- scenarios that Newtonian gravity handled well. "In retrospect, this is just a bizarre mistake," said Norton. To correct this perceived flaw, Einstein thought he had to abandon what had been one of the central features of his emerging theory. Einstein's field equations -- the equations of general relativity -- describe how the shape of space-time evolves in response to the presence of matter and energy. To describe that evolution, you need to impose on space-time a coordinate system -- like lines of latitude and longitude -- that tells you which points are where.
Another interesting read on Quanta: Why Stephen Hawking's Black Hole Puzzle Keeps Puzzling.

9 of 119 comments (clear)

  1. Re:FRAUD by Anonymous Coward · · Score: 2, Insightful

    Oh, hi Ken. Thanks for sharing your videos with us. But why post here 3x as AC? Just come out and own it.

  2. Was it a mistake? by tomhath · · Score: 5, Insightful

    the monumental effort to reconcile general relativity with quantum theory flounders in part because of the difficulty of developing a theory of quantum gravity that has the same general covariance Einstein achieved with his field equations. “In some sense you could argue the reason we don’t have an adequate quantum theory of gravity is we don’t know how to express the solutions to Einstein’s equations in a way that completely removes any kind of coordinate dependence,” said Weatherall.

    It sounds like he recognized that there was something he couldn't explain, so he backed off a bit and looked for the explanation rather than charge forward and risk looking foolish.

  3. Re:Questions by Anonymous Coward · · Score: 5, Insightful

    What actually happens when matter turns to energy and back?

    It has never been observed to completion, only buildup of mass on high-speed particles and significant energy release on disassembly of atoms.

    What's the difference between energy that is electromagnetic and energy that is motion?

    How it interacts with other energies.

    Why the difference?

    They are essentially different, but also somewhat similar. That's why you are having trouble disconnecting the similarity in names from the difference in meaning.

    Can you turn motion energy into photon energy?

    There are many means of conversion.

    Why not?

    False.

    Where does the value of C come from?

    Observation and calculation.

    Why is there a limit at all?

    We suspect there is a limit because Maxwell's Equations have an asymptote at that value. We accept that there is a limit because high energy testing shows the predicted behavior.

    Why is that limit exceeded by observation?

    It hasn't been.

    How come there are so many forces?

    There are 4.

    Why is gravity only an attraction force and others not?

    Gravity and the strong nuclear force are attraction, the weak nuclear force is repulsion. Magnetism is directionally attraction.

    What is time?

    A direction.

    Why does inertia and momentum require time?

    By definition.

    Why don't things happen instantaneuosly?

    Things do, and trends don't.

    What if they do? How would we perceive that?

    You wouldn't. At best, your perception is functional on the order of 10^42 hypothetical distinct moments per AC observation.

    What would motion look like in a world where everything happens instantaneously?

    Have you been to a rave with a strobe light? Start from there.

  4. Risked Missing Out On Fame by Anonymous Coward · · Score: 0, Insightful

    To gain tremendous scientific integrity. It takes a truly great scientist to question his own theory and risk not "being the first". In the end though, this is better for the scientific community as a whole. Science is about asking questions, observation, and hypothesizing outcomes and it shouldn't stop just to "be the first". Just look at the ego centric origins of the theory of evolution and you will see a "me first" cock measuring contest (or finch measuring contest but I'm sure they are both birds and related). Hint you might find it wasn't Charles Darwin even though his name is stamped all over it.

    1. Re:Risked Missing Out On Fame by tinkerton · · Score: 3, Insightful

      Such a bad example. Darwin delayed much longer than Einstein and it's doubtful whether anyone forced his hand at all.
      He was a brilliant thinker who deserves full credit. Wallace didn't come close in any way.

  5. Re:FRAUD by Anonymous Coward · · Score: 2, Insightful

    Not only is Ken Wheeler testably false, but the falsify-ability of the electric/magnetic universe theories created the need for relativity.

    If you think there's some physicist conspiracy to keep Einstein in that position, you're stupid wrong. When someone breaks Einstein with a repeatable, testable theory, they will unseat Einstein the same way Einstein unseated Newton.

  6. The evidence suggests not by Roger+W+Moore · · Score: 5, Insightful

    In this era of computers and CPU's and constant distraction, he wouldn't have managed to get to even first realization.

    ....and yet there are thousands of papers published by theorists each year which suggest that people still manage to come up with abstract new ideas in fundamental physics for us to test in our experiments. While it is true that none of these have been as significant as Einstein's papers that's not surprising: if papers this significant came up on a regular basis it would mean that we were doing a really bad job figuring out how the universe works. There were 200 years between Newton and Einstein and another hundred years later we are still only just seeing some of Einstein's predictions for the first time with gravitational waves being the latest discovery.

  7. Re:FRAUD by meglon · · Score: 4, Insightful

    ...and yet every experiment to verify Relativity has shown Einstein to have been correct, whether it was 4 years after, or 100 years after publishing. Your stupid fucking electric universe bullshit requires Relativity to be wrong, yet everything points to Einstein being right.

    Your pseudoscience cult is just fucking stupid.

    --
    Fascism: An authoritarian and nationalistic right-wing system of government and social organization. See also: NAZI's
  8. Re:Einstein wouldn't happen today by Anonymous Coward · · Score: 2, Insightful

    If Einstein didn't come up with it, someone else would have in the next 5 years. He wasn't working in a vacuum. The idea that matter and energy are interchangeable some way was already well on it's way by Poincaré and others before Einstein. Lorentz already described time dilation and the Lorentz transformations is pretty much the basis of special relativity.

    Look at Hawking and the state of the art now in theoretical physics. You have many people that are/were probably on the same level as Einstein was, it's just getting more and more complicated to come up with new shiny groundbreaking theories.

    If anything, research will more faster, because there are more ways to communicate.