system
Given the following post, respond as if you're commenting on Reddit:
human
If there was a planet orbiting at the exact same speed as the Earth, in the same orbital path, but on the other side of the sun from the Earth, would we know about it by now? How would we figure that out?
gpt
We'd know about because a. Earth's orbit isn't perfectly circular so there'd be phases of the orbit where the sun isn't blocking it and b. its gravity would disrupt the space probes we send to Venus and Mars, but those probes haven't been disrupted. If such a planet exists it would have to be small enough to be a Russel's Teapot.