I've been researching logical ways to explain an earth-like amount of gravity on mars for my sci-fi book idea and I can't seem to find a good explanation to back up gravity other than "gravity was magically restored by gravity machines." Which is ridiculous. I want to put some logic behind my writing. So if anyone can help me with a way to restore gravity on mars, that would be great! So far I've seen: the use of magnetism for gravity, centrifugal force(would only work on huge space stations) and things of that nature. Magnetism seems the way to go but i need to know how to explain it a tad so the reader doesn't question it.