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Name: Nicholas G.
Status: student
Age: 5
Location: N/A
Country: N/A
Date: Thursday, September 12, 2002

Why can we see the moon and sun during the day at the same time but cannot see the sun at night?


You can see them in the daytime because they are in the sky where you are looking. You cannot see the sun at night because it is hidden on the other side of the earth.

ProfHoff 471

Hi Nicholas,

You have asked a very cool question. Now I am going to ask you one. Did you know that the Earth is a big round planet that travels through space around the sun? Besides our Earth traveling around the sun, it also spins around one whole time every single day.

Now imagine yourself outside. Mom is standing in front of you and dad is behind you. Now spin. When you spin, sometimes you can see dad and not mom. Sometimes mom and not dad. But both of them are always there. Same thing with us and the sun. In the day time we are facing towards the sun and at night we are not. The sun is there, we just cannot see it from where we are. When it is night time here it is day time on the opposite side of the Earth and all those kids are up and playing.

Now the moon travels around us just like we travel around the sun. It is on a totally different time schedule. It takes us (on the earth) one year, (365 days), to make the trip around the sun, but it only takes the moon 28 days to make the trip around the Earth. So sometimes during the day we can see the moon because it is just moving around us faster.

Ask mom or dad to take you to the library to get some really cool books on the Solar System. They will probably have good explanations along with some really neat pictures.

Good luck on your planetary adventure.

Mrs. Croll


What we call day is the part of the time when we can see the sun. What we call night is the part of the time we cannot see the sun. This is because daylight comes from the sun.

Sometimes the moon is close to the sun. This is when you see the moon during the day but not at night. Sometimes the moon is very far from the sun. This is when you see the moon at night but not during the day. Sometimes the moon is in between: part of the day and part of the night.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College

Remember, the earth revolves about the sun, and the moon revolves around the earth. Also the earth spins on its axis, like a spinning ball. If we are on the side facing the sun, the sun shines. If you are on the side facing away from the sun, it is dark. Because both the earth and moon are revolving around the sun, there are times when sunlight shines on both. You can see this by taking a flash light (the sun) and shining it on two balls -- say a golf ball (or marble), and a baseball or soccer ball (the earth). Put an 'X' on the earth (that is you) and let it turn around. You will see that sometimes the 'X' is in the light and sometimes it is not (that is, day and night). Then let the smaller ball move around the larger ball. You can see then that sometimes it and the 'X' are in the sun light, one is in the sunlight and the other is not, or neither the "moon" nor the 'X' are lighted by the flashlight.

If you go the web site: you can see the dark and light parts on the earth as you move from time zone to time zone. On that web site, the earth is "flattened out" so that it can be shown on the screen, but remember the earth is really a "ball".

Vince Calder

Since the sun is the source of daylight whenever we can see the sun it is daytime.

Note also that we cannot always see the moon during the day. Only when it is on the side of the earth closest to the sun. When the moon is on the side of the earth furthest from the sun we only see it at night. It takes about a 4 weeks for the moon from one side of the earth to the other. So we see it at night for two weeks and then during the day for two weeks.

Greg Bradburn

You can see the sun during the day because daylight comes from the sun and when there is daylight, it is daytime. At night the sun is behind the earth and so its light cannot be seen.

The moon is visible only when it is on your side of the earth, so it is not always visible during the day or during the night.

But the sun and the moon are always there in space and always emitting light. If you went up in a spaceship and were far from the earth, you could always see both the sun and the moon. That would take a while to get used to, since there would be no daytime or night time.

Richard J. Plano

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