# How large would a alien spaceship have to be to affect the earths gravitational orbit? [duplicate]

Would a large enough ship generate enough gravity to affect earths course?

## marked as duplicate by Organic Marble, uhoh, called2voyage♦Sep 26 '18 at 16:11

Any spaceship (or other mass) anywhere in the universe will affect Earth's orbit. Just not very much! For instance, a 1 million ton stealth spaceship magically hovering just above the surface of the Earth would accelerate the Earth at about $$10^{-15} m s^{-2}$$ towards it. This would give a displacement of about 0.5 meters over a year.