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Einstein's description of gravity just got much harder to beat

phys.org

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Re: Einstein's description of gravity just got much harder to beat

#2
Actually, it just got easier to beat. What happened was scientists found a new way to measure the effects of gravity that can substantially distinguish between different proposals to unify general relativity with quantum mechanics.

The article says it got "harder" because the theory of general relativity wins every measurement, and that means the search space for potential solutions is much smaller - you have more constraints that you need to fit.

But this is actually a good thing. Finding the right theory is like looking for a needle in a hay stack. These new measurements are the functional equivalent of removing a huge portion of the hay.

Yes, it means there are now fewer places to check, but that's actually what we want. We'll spend less time chasing dead ends because it's easier for us to see they are dead ends sooner.

Re: Einstein's description of gravity just got much harder to beat

#3
post #2

Actually, it just got easier to beat. What happened was scientists found a new way to measure the effects of gravity that can substantially distinguish between different proposals to unify general relativity with quantum mechanics. The article says it got "harder" because the theory of general relativity wins every measurement, and that means the search space for potential solutions is much smaller - you have more co…

Thinking like an engine “taking relativity apart” and going over its pieces for flaws, finding a piece that’s broken, but needing such a highly customized piece to maintain consistency of the engine and maybe link it to quantum mechanics hasn’t really done away with the possibility we’ll chase thousands of dead ends first.

It got easier but “easy” relative ;)

Re: Einstein's description of gravity just got much harder to beat

#4
> Despite its successes, Einstein's robust theory remains mathematically irreconcilable with quantum mechanics, the scientific understanding of the subatomic world. Testing general relativity is important because the ultimate theory of the universe must encompass both gravity and quantum mechanics.

Maybe the universe just has a giant if statement.

Re: Einstein's description of gravity just got much harder to beat

#5
During brainstorming sessions, I often think about why/how medieval artists couldn't quite grasp how to depict depth in their paintings (as a lateral thinking technique). Being humans living in the world, they obviously experienced and understood that depth existed all around them, but had a hard time grasping the concept as a whole. I feel like we're kind of in a "medieval depth" phase of gravity/spacetime understanding...it's literally all around us, we know something is there, but we can't quite grasp what it even is we're looking for.

Re: Einstein's description of gravity just got much harder to beat

#8

I don't quite get it they say relativity and Quantum Mechanics are incompatible. Does that mean they give different predictions?

No. They cover different domains, so their predictions within those domains are consistent (and non-overlapping). It is combining them that is the problem.

Re: Einstein's description of gravity just got much harder to beat

#9
post #6

Can some knowledgable person articulate why physicists are so sure that QM and GR are incompatible?

Rather it is the belief that they fundamentally must be compatible that is driving this research. Currently we don't know how to answer questions like "what is the gravitational field around a photon?".
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