The slowest moving animal is a crab found in the Red Sea. It travels with an average speed of 5.7 Km/year How long will it take this animal to travel 100 km?

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?