Wednesday, November 5, 2014


imagine there would be a planet identical in mass as our Earth circling the Sun in our orbit with a lag of exactly 6 months, i.e. it would always be behind the Sun and not directly visible for us. would there be nevertheless possibilities of detecting it?


  1. This is a very interesting question. I think it would be very easy for us to detect this planet if we knew what we were looking for. But what I think is more likely is that we would not ever find evidence that this anti-planet existed, thus we would have no reason to look for it. Why would we look for another planet in our same orbit pattern on the other side of the sun for the heck of it? What I think would most likely happen is that the anti-Earth would be accidentally discovered during a manned space mission.

    Thank you for posting this question. If you'd like to check out my blog, it's full of post about cosmology and topology and stuff. I think you may find it interesting.

  2. Sure. It will perturb other planets.

  3. thanks, JazzOboe and Phillip, for your answers. CQW just would like to add that we find it remarkable that there are no Doppler-shifts from the surface of the Sun that would help to distinguish the two cases.