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Einstein's Theory Passes Strict New Test
FiReaNGeL writes with an excerpt from a story at e! Science News: "Taking advantage of a unique cosmic configuration, astronomers have measured an effect predicted by Albert Einstein's theory of General Relativity in the extremely strong gravity of a pair of superdense neutron stars. Essentially, the famed physicist's 93-year-old theory passed yet another test. Scientists at McGill University used the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT) to do a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves."
Usually pop culture gets these people's character pretty wrong. Elvis, for example, is "the King", when he was just a singing truck driver.
But Einstein they got pretty right. Sure, he didn't know everything, was smart really only within his very narrow discipline of mathematical theoretical physics. Einstein himself used to say "I really only ever had 4 good ideas, and 2 were wrong". But the couple he was right about, he was really right.
And with the wild hair, the pacifism, the "same suit every day so I don't have to waste time thinking about it", and the snappy short equations that explain everything, he's probably the coolest smart guy since they all used to wear togas and live on wine and souvlaki on the beach.
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make install -not war
Feynman's take was that light is *always* particles. He was unequivocal about that.
My understanding is that relativity has been directly observed several times, whereas quantum theory is still just based on the interpretation of a series of controlled laboratory experiments, which mostly amounts to sifting through the wreckage of a high-energy collision and trying to derive the original state from the leftover pieces.
Oh, just based on a series of controlled laboratory experiments. Unlike relativity??
I have no idea what "directly observed" means, but quantum mechanical behavior is no less directly observed than relativistic behavior. In fact, it is far better studied, since atomic physics is more accessible to experiments than relativistic physics. And it by no means is limited to high energy colliders (which is where you tend to see relativistic effects the most, by the way); atomic spectra, basically all of chemistry, condensed matter and material science, lasers, etc. all depend on quantum physics. Indeed, the quantum theory of electrodynamics is the most precisely verified theory in the history of physics; some of its predictions (like the electron g factor) are accurate to something like 12 decimal places when compared to experiments.
Isn't it about time to abandon the concept of the graviton and just accept that gravity is not a fundamental force, but is simply the observed effect of the curvature of spacetime due to the presence of matter and energy?
If you accept that matter is described by quantum mechanics, then general relativity is wrong, because you can't consistently couple a classical field to a quantum source. (Consider what happens when you want to describe the gravitational field of matter which exists in a quantum superposition of states.) Believe me, if it were that easy to produce a theory of gravity which is consistent with what we know about matter, people wouldn't have been searching for 50+ years for a theory of quantum gravity.
Once you accept that gravity needs to be quantized, then you are inevitably led to something like a graviton: it's what you get when you quantize the linearized approximation to general relativity, and is actually more general than that: any field which couples to stress-energy (which is the source of gravity in general relativity) is described by a rank-2 tensor, which in quantum mechanics means a spin-2 particle (graviton). A theory of quantum gravity won't have gravitons as truly fundamental — the perturbative theory of gravitons is inconsistent — but any such theory (e.g., string theory, loop quantum gravity) will necessarily have graviton-like behavior as a low energy limit, assuming that it also has a relativistic theory of gravity (like general relativity) as a classical limit. That is not inconsistent with GR's description of gravity as curved spacetime: that's the classical behavior of a graviton-like field, although different theories recover that limit in different ways. (String theory has strings which vibrate in graviton-like ways which are observationally indistinguishable from spacetime curvature; other theories try to quantize geometry directly.)
How is geometry underrated? Calculus starts with the study of low dimensional curves. Linear algebra is the study of simple geometrical transformations (rotations, translations, dilations) in high dimensional geometry. Functional analysis is basically the study of infinite dimensional flat geometry. Partial differential equations are implicit equations for small patches of curves and surfaces. That's about half the usual curriculum in undergraduate mathematics, and I haven't even mentioned differential geometry (generalized theory of curves and curved spaces) and algebraic geometry (generalized study of the properties of curves defined by polynomial equations).