Would any planets or Kuiper Belt Objects be seen from Eris with the Naked Eye?
Fascinating question. Eris has an extremely elliptical orbit, as is currently near aphelion, so the answer would change between now and when it is at perihelion in a few millennia. The first problem, particularly now, is that the planets would all be so close to the Sun in the sky that even though the Sun would be no more than a dot, it would be so bright that you could not see any planets near it. Of course, if you had some method of occulting the Sun Jupiter and Saturn would be naked eye visible when Eris is near perihelion. As for other KBOs, only a few bright ones have been found so far, and they would very rarely be near enough Eris to be visible, since all are small and most have a low albedo. Eris has a moon, Disnomia. Because the the Sun’s distance, it would be extremely dim even when full. I estimate it around fifth magnitude at best (had to assume an albedo).
