is acting on an object that is constrained to move along the x-axis. If the force moves the object 3m, from the origin, what is the potential energy difference due to this force acting on the object

The seven sisters, seven stars located more than 400 light-years away in the taurus constellation can be seen here with venus and another constellation, orion. the seven stars stay grouped together but seem to move, like the planet venus. why do stars seem to move like planets in the night sky?