As a dad of 2 great kids I was asked this question by my youngest last night.?

Question

If the earth is revolving why is it we can see the moon/sun/stars in a fixed position ?
What do I tell her.

Answer 1

Tell her that the motion is very slow.

Then Show her that the moon/sun/stars seem to move slowly across the sky.

Watching the sun set is one easy observation. Explain that as the Earth moves (rotates toward the east) the sun seems to set (in the west).

Answer 2

Excellent question, but terrible answers: mostly guesses, and wrong ones at that!

The Moon, Sun. and stars are not in a fixed position, it's just that the motion of the Earth is so slow and smooth we can't easily detect their motion. When I bring my telescope to star parties at schools, I usually bring one without a motor drive. With the extra magnification of a telescope, the kids immediately notice how fast the Earth is actually rotating, as objects zip through the field of view.

Without a telescope, it's a bit harder to demonstrate this, but I saw it clearly last night with the naked eye. I noticed a patch of red in the woods to my east, and realized that it was the Moon, just above the horizon and trying to get its light through the polluted skies at that low altitude. Over a five minute period (about as long as a small child can tolerate!) I watched it slowly rise until it cleared the tops of the trees and became noticeably brighter and less red in colour. So you need to find a star, planet, Moon, Sun which is right on the horizon, just rising or setting, and watch it with your child for a few minutes until its motion is obvious. The Sun or Moon move their own diameter in about two minutes, so it desn't take long when you've got a good reference point on the horizon. Right now, Jupiter is low on the southern horizon at dusk for most of us in the northern hemisphere, and it's motion is quite obvious over half an hour if you have buildings and trees to the south.

By the way, this has absolutely nothing to do with how far away things are, as many answers suggest. Whether it's the Moon or the farthest galaxy you can see with the naked eye, all are apparently moving across the sky with the same speed. It's just that the Earth's rotation is relatively slow (360° in 24 hours, 15° in 1 hour, 30' (diameter of Sun or Moon) in 2 minutes) and extremely smooth.

Answer 3

That it is an illusion. The stars are all moving. But at a short glance they appear not to.
Buy a telescope. Or if you have a camcorder put it on a tripod and zoom in fully at the moon one night. You and your clever, inquisitive kids will be able to see with your own eyes how the moon is moving. Because there are no fixed positions in space. The stars and the moon travel across the sky just like the sun rises and sets. If the earth wasn´t revolving around its own axis there wouldn´t be any sunrises or sunsets. We could still see the moon move as it orbits earth but less pronounced. Same with the stars as earth orbits the sun. The stars all move relative to each other too but they are so far away it takes really advanced measurements to make out that movement.

Answer 4

You got an INCREDIBLE number of BAD answers.

There is a very simple way to make this clear to a bright and inquisitive child.

Just draw her attention to the hour hand of a clock, and let her observe that the hour hand does not appear to move. Now suggest that the two of you check the hour hand about every 30 minutes and see if it has moved. Expand from this to point out that there are things that move so slowly you can't see them moving very well, but over time you notice the difference.

Now explain that the stars in the sky are moving from east to west at a speed similar to that of the hour hand. Actually, the hour hand moves twice as fast in angular terms, but you probably don't need to go into that. She will point that out to you when she is about 15.

To finalize the point, have her take note of the position of a prominent object like the constellation Orion and check it again every hour or so until her bedtime. That may be easier later in the year.

She will get the idea.

Don't pay too much attention to any of the other answers. Most of them are at least partly wrong. And I know for sure the "clock hand" method works with children.

Answer 5

I will jump in and try to explain it.
Because the earth is rotating the stars rise in the east in set in the west just like the sun

Because the are stars so far away the revolution around the sun doesn't affect the position much.

Imange you are looking at two tall buildings that are 100 feet apart and you took two steps to your left.
Their positions would not appear to change.
Scientists can notice difference in stars as we revolve around the sun.
If you measure the angle to some stars in January and then wait until June and measure the angle again. It will have changed a tiny amount because the Earth has moved half way around the sun and we are looking at it from a different point in space. It is such a tiny difference that you would not notice it unless you measured it with a very precise instrument.

Answer 6

We see the sun in a constant position BECAUSE we are revolving around it. As an example, take a baseball and set it in the lawn. Now, walk around it in a circle. It seems fixed.

The stars, on the other hand, are so far away that a little movement on Earth's part doesn't matter so much. By way of example, pick a house on a distant hill, and one across the street. Walk 30 feet. The distant house is in much the same position. However , your perspective on the closer house has changed dramaticlly.

The stars change seasonally, by the way. Buy a star gazing guide ( or get one from the library) and show your child the wonder of the heavens as the new constellations appear in the sky.

Answer 7

There is a simple experiment that can be done with a digital camera that has a timed exposure on a clear night. Find a dark spot in the garden that has clear sky above it and place a chair or table there. On the table place your camera with the lens facing vertically upward. If you set for a timed exposure of an hour or so, when the shutter closes you should have a picture of the stars with trails of light behind them. This shows that the Earth has slowly moved under a fixed sky.
Don't do this on a wet night or you'll ruin you camera. Good Luck.

Answer 8

Tell her they only seem to be in a fixed position because although the Earth spins, it is so large that the moon/sun/stars only seem to move very slowly, too slow to be seen in a short time.

The Earth only spins at 1 revolution every 24 hours; although the surface moves at about 600 - 1000mph depending on whereabouts you are on it, the huge size it means that the stars move very slowly across the sky. Look at the moon at 6pm and then again at 7pm and she'll see it has moved. In fact, you can see it move by looking at it through a telescope - fix your sight on the brightest edge and watch the moon move across your field of view !

Answer 9

Have her stand in the center of a room and slowly turn explaining that that takes an entire day. She will notice that everything on the walls remains fixed. Have only one table lamp on representing the sun and night and day as she turns. Move around her like the moon which is much closer than the sun but explain that for you to circle the room takes about a month or about thirty times for her to turn around. The stars are so far away that they barely move in a lifetime.

Answer 10

The objects in the sky do move around, just so slowly that they seem to be static. The Sun casts shadows, and these move as the Sun travels across the sky - that's how sundials work.

If you have a movie camera capable of time-lapse photography. you can use this capabillity to show the stars moving across the sky too. Alternatively, you can leave a 'stills' camera's shutter open on a clear night - you needn't leave it for more than about 30 seconds to produce a picture which shows the stars starting to make trails.

I hope this helps.

Answer 11

We don't see them in a fixed position at all.
We see the sun and stars rise and set on a 24 hour period, this is due to the Earth revolving - as we go round, we look out on the universe in a different direction.