Personally I believe string theory is a very strong candidate for a quantum theory of gravity, for it has been able to correctly satisfy various consistency checks (like the calculation of black hole entropy) with great success. String theory and loop quantum gravity are the leading approaches, with other approaches too being practiced. The geometric foundation for his work was laid some 60. Albert Einstein changed our view of the universe in 1915 when he published the general theory of relativity, in which he set forth the notion of a four-dimensional spacetime that warps and curves in response to mass or energy. Contents 1 Details 2 Manipulation 2.1 Pregnancy Chance 2. June 10, 1854: Riemann’s classic lecture on curved space. Captain Steele is able to become pregnant, be impregnated (and inseminate and impregnate others), in a variety of ways, possibly giving birth in several ways as well. There are a handful of approaches to quantum gravity as are given on this Wiki page. Sex in the Trials in Tainted Space universe has consequences and pregnancy is one of them. A theory of quantum gravity should yield calculations consistent with corrections to the Bekenstein-Hawking entropy. In order for a theory of quantum gravity to be "alright", one looks at consistency checks which a quantum theory of gravity needs to satisfy. It is viewed more as an effective field theory than a full theory. QFT in curved spacetime therefore isn't designed to be a quantum theory of gravity, but serves as a good tool and reveals some nice features using standard methods of QFT. Einstein taught us that objects moving under gravity are simply moving with constant (i.e., parallel-transported) four -velocity through curved space time. The 3D acceleration in Newtonian gravity is merely an artifact of the coordinate systems we use for Newtonian physics. In the question details you also asked how an object with mass can (remotely). In curved spacetime, objects don’t accelerate under gravity. The issue of non-renormalizability of gravity as a field theory also needs to be taken care of in a full theory of quantum gravity, as infinities are there due to loops in Feynman diagrammatic expansion which cannot be renormalized, and one requires an increasing number of counterterms at each loop so as to absorb up divergences. In addition, curved spacetime is not a kind of curved space. That means assuming that the quantum fields don't change the background metric, which shouldn't be the case in a theory of gravity.Īlso in examples like calculation of black hole entropy, a quantum field theoretic treatment yields an infinite entropy (as opposed to the finite Bekenstein-Hawking entropy which is obtained semiclassically, for the full field theoretic treatment a distance cutoff is needed as in the brickwall approach of t'Hooft, which violates the principle of relativity), an issue which can be traced back to non-renormalizability of gravity as a field theory. It is defined only on background dependent scenarios, i.e. QFT in curved spacetime is not viewed as a full quantum theory of gravity but rather as a first order approximation to it.
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