Have you ever been on a merry-go-round? People sit on fake horses that move up and down while the ride rotates, or spins around. If you have a family member or a friend standing next to the ride, you might wave to them as you go around (and around and around…) It’s pretty clear that the ride is spinning because you keep passing the same things and people as you travel around.
The Earth rotates too. It takes twenty-four hours for it to spin around completely, and that’s the length of our day. Since we’re on the Earth, we spin around with it. It’s like we’re on a ride. The reason it doesn’t feel like we’re spinning around is because the Earth is so big and everything on it moves too! All trees, buildings, people, cars, rivers, and everything else on Earth are on the ride too. Since everything is moving together, it’s very hard to tell that we’re moving at all. It looks like everything stays in the same place.
A big clue that lets us know we’re rotating is the Sun. The reason it looks like it’s moving through the sky is because we’re spinning past it.
Did you realize the stars move in the sky at night? Well, it’s really the movement of the Earth that makes it seem like the stars are moving. As they move across the sky, can you spot any constellations? Constellations are groups of stars that make different shapes in the sky.
Have a grown-up help you find some pictures of constellations. What ones can you spot as the stars seem to travel?
The big dipper is a pretty easy one to spot. So is the little dipper. The constellation Orion is one that is pretty easy to recognize too!
Do the constellations seem to be in a different spot in the sky every night? What do you think causes that?
Sources & links
Dibon-Smith, Richard “The Constellations.” 2001. 12 September 2009