The opposite of Earth, but identical in all aspects, can be called Antiearth. Similar to Earth, Antiearth would be a celestial body with an atmosphere, oceans, diverse ecosystems, and a human-inhabited planet. However, there would be a fundamental difference in their gravitational charges. While Earth has a positive gravitational charge (+1), Antiearth would possess a negative gravitational charge (-1). This unique quality would mean that when Earth and Antiearth collide, their opposing gravitational forces cancel each other out, resulting in a net equilibrium of zero.