text: a hidden planet behind the sun? imagine: there is a planet that always behind the sun, so we can not see it from the earth. it rotates similar like earth, using earth's track. if that planet really exists, it could be occupied by ufo.  do you agree? nasa sent probes to mercury and venus but didn't find any other planet besides that. the one sent to venus has a flight path that circles the sun before it reaches venus. if there are any planet hiding behind the sun they'd already found it.