I was just curious if it would be possible for another Earth and Moon to exist in our solar system neighborhood. What I mean by that is for it to exist as close as possible to our planet so that it can have the same sort of atmospheric temperature and by extent, similar living conditions, this is where I am getting at. I am pretty sure that to those who are educated on this subject, this is problematic because I suspect this other planet would affect ours in negative ways ? Anyhow, I hope I conveyed my message clear enough. What about just another Earth-like planet without a natural satellite ? Would it change the said planet so much that it would be drastically different compared to our Earth ?