Despite keeping us grounded and warping light that travels through space, gravity is actually quite a weak force. The smaller the mass, the less gravity appears to have any pull, until at quantum scales it appears to have no force at all.
If you asked an astrophysicist what is yet to be discovered in the universe, there’s a good chance they’d paraphrase Donald Rumsfeld: It’s full of known unknowns.
The quantum world operates by different rules than the classical one we buzz around in, allowing the fantastical to the bizarrely normal. Physicists have described using quantum entanglement to simulate a closed timelike curve—in layman’s terms, time travel.