Linked Questions

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1answer
285 views

If gravity arises from the curvature of spacetime, why is there a need for gravitons? [duplicate]

If gravity arises from the curvature of space time, why is there a need for gravitons? If someone could explain this to me I would be very thankful. I dont understand why.
59
votes
8answers
39k views

What are the reasons to expect that gravity should be quantized?

What I am interested to see are specific examples/reasons why gravity should be quantized. Something more than "well, everything else is, so why not gravity too". For example, isn't it possible that a ...
76
votes
6answers
5k views

If gravity is a pseudoforce in general relativity, then why is a graviton necessary?

As far as I’m aware, gravity in general relativity arises from the curvature of spacetime and is equivalent to an accelerated reference frame. Objects accelerating in a gravitational field are in fact ...
34
votes
5answers
4k views

Is the graviton hypothetical?

Wikipedia lists the graviton as a hypothetical particle. I wonder whether graviton is indeed hypothetical or does its existence directly follow from modern physics? Does observation of gravitational ...
32
votes
4answers
12k views

Why is gravity so hard to unify with the other 3 fundamental forces?

Electricity and magnetism was unified in the 19th century, and unification of electromagnetism with the weak force followed suit, bringing into play the electroweak force. I've been told that ...
12
votes
1answer
2k views

Why does gravity need to be quantised?

The electroweak and strong forces seem to be completely different types of forces to gravity. The latter is geometric while the former are not (as far as I'm aware!). So why should they all be ...
6
votes
2answers
2k views

Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon?

Does String theory say that spacetime is not fundamental but should be considered an emergent phenomenon? If so, can quantum mechanics describe the universe at high energies where there is no ...
9
votes
2answers
864 views

Is quantum gravity, ignoring geometry, the theory of a fictitious force?

This question is motivated by this question and this one, but I will try to write it in such a way that it is not duplicate. In short, I don't understand the motivation for a "quantum theory of ...
3
votes
4answers
722 views

What predictions can a quantum gravity theory make?

Some of the major challenges that heralded the need for quantum mechanics we're explaining the photo-electric effect, the double-slit experiment, and electrons behavior in semi conductors. What are ...
0
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1answer
1k views

We Don't NEED Quantum Gravity because Gravity isn't Even A Force! [duplicate]

Now, I understand the motivation for quantum gravity. I honestly want to work on a theory myself. However, gravity, according to General Relativity, is not a fundamental force of nature. To me, it's ...
2
votes
3answers
344 views

Is gravity a fundamental law that is taken for granted?

The question might seem silly (and, maybe it is ), but I would like to know if gravity is really something you can not explain in some other terms and have just to take for granted (i.e. it simply ...
6
votes
1answer
566 views

Is the quantization of gravity necessary for a quantum theory of gravity? Part II

(At the suggestion of the user markovchain, I have decided to take a very large edit/addition to the original question, and ask it as a separate question altogether.) Here it is: I have since ...
0
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1answer
146 views

What if quantum mechanics and general relativity are not connected? [duplicate]

The main objective in modern physics research is to find a way to unify quantum mechanics and general relativity thorugh a series of theoretical approaches called "quantum gravity theories" But what ...
1
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2answers
189 views

Why do black holes need a quantum mechanical description?

I read about black holes, about the Schwarzschild metric, Einstein field equations and their solution in the vacuum for a spherical body. I understood black holes are object whose gravity is enormous,...
1
vote
2answers
143 views

What is the motivation for developing a “theory of everything”?

What is the reason physicists are working so hard looking for a "theory of everything" and trying to unify gravity with quantum mechanics? Historically, new theories were always developed to explain ...

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