Question

Why there is no quantum gravity ??

Answer 1

One of the difficulties of formulating a quantum gravity theory is that quantum gravitational effects only appear at length scales near the Planck scale, around 10−35 meters, a scale far smaller, and hence only accessible with far higher energies, than those currently available in high energy particle accelerators.

Answer 2

$answer$

Of the universe's four fundamental forces (gravity, electromagnetism, and the strong and weak nuclear forces), only gravity lacks the "quantum" description. As a result, no one knows for sure (although there are plenty of ideas) where gravitational fields come from or how individual particles act inside them.