system
Given the following post, respond as if you're commenting on Reddit:
human
Just as we can create and manipulate an electromagnetic field, is it physically possible to create or manipulate a gravitational field?

Gravity is a strange force. Could we create it without using mass?
gpt
Why without mass? You can't create an electromagnetic field without charge.

Anyway, to answer your question we can create gravitational fields by putting lots of heavy stuff in one place, as Cavendish did when he measured the gravitational constant. Gravity is indistinguishable from acceleration, so we could mimic gravity by having something that is constantly accelerating.