Actually, science can more or less prove that's NOT the case.  Well, cool. That’s why I asked.  There is a “more or less” there though.  So cool that too.  There's a lot of mathematics that goes into calculating orbits, and I strongly suspect that another major object in a similar orbit around the sun would have an affect on its opposite body.  So…a strong suspicion or theory again; hmm, interesting once more.  Furthermore, unless the opposing planet has EXACTLY the same mass, its orbit would necessarily change in relation to the sun, as would its speed.  Either of these would eventually render it visible to us.  Again, supposition…so cool; that is, who’s to say the duplicate planet is not EXACT in all its specifics.  Also you use the word, “eventually,” which, perhaps true, may not have arrived yet.  Going on that principal though, one would have to give credence to the effects of the inhabitants on the diametrically opposed planet masses: whether or not those effects would modify the specifics enough to mathematically alter the rotation of one to the other.  Hmm…interesting.  But keep it coming.  You're on a roll today.  The posts are both intellectually and visually stimulating.  Kind of you to say, Ross.  & cool that you responded ~~ being one of the comparatively levelheaded panelists that may act as a balancer unto th fulcrum o thought on this arbitrary teeter-disfunctional-totter-community somewhere between rationalism & artmatter/artslather that gets us two steps forward and one step back or one step forward and one step back or one step forward n two steps back.........