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Author Topic: Why is the moon visible during the day?  (Read 9541 times)

Peter Williams

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Why is the moon visible during the day?
« on: 10/05/2008 21:23:09 »
Peter Williams  asked the Naked Scientists:

Hello,

This is probably a stupid question, but it's one that's bothered me for a long time:

Why is the moon sometimes visible during the day, at a time when presumably it should be over the Americas?

Love the podcast and thanks in advance.

Peter Williams
Livingston, Scotland


What do you think?


 

lyner

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Why is the moon visible during the day?
« Reply #1 on: 10/05/2008 22:37:24 »
The Moon goes around the Earth. The Earth rotates. The two periods are different (28days approx and 24 hours) At any particular time of day the Moon can be at any position, depending on the time of the month. It may be overhead or round the back of the Earth. When it's in the sky in the day, it is just another object being lit by the Sun - so we will see the parts that the Sun is shining on.
btw, when you photograph the Moon at night, the correct exposure would be about the same as for a daylit scene - it's an object in full sunlight!
 

Offline JimBob

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Why is the moon visible during the day?
« Reply #2 on: 11/05/2008 15:14:10 »
It is big and round and close to the earth.
 

lyner

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Why is the moon visible during the day?
« Reply #3 on: 11/05/2008 23:26:07 »
A cheese in flight?
 

Offline daveshorts

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Why is the moon visible during the day?
« Reply #4 on: 12/05/2008 15:29:28 »
here is a little flash animation I wrote a few years ago showing the moon orbiting the earth.

http://www.chaosscience.org.uk/pub/public_html//article.php?story=2004062914222354

When the moon is on the sunward side of the earth you should be able to see it during the day. Normally during the day the side of the moon pointing towards us is in shadow, so you won't be able to see it well but it is still there.
 

Offline caboose17

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Why is the moon visible during the day?
« Reply #5 on: 16/05/2008 20:07:47 »
also did you know that the moon doesn't rotate on its axis, so one side is always facing earth.
 

lyner

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Why is the moon visible during the day?
« Reply #6 on: 16/05/2008 21:05:58 »
Actually, it rotates once a month!!!
 

Offline caboose17

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Why is the moon visible during the day?
« Reply #7 on: 26/05/2008 03:26:59 »
it rotates around the earth every month. But it doesn't rotate around its axis at all!!!!!!!!!! try reading everything i write next time!!!!!
 

Offline Soul Surfer

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Why is the moon visible during the day?
« Reply #8 on: 26/05/2008 09:37:30 »
The moon DOES rotate on it axis it takes exactly the same time to rotate as it takes to complete its orbit if it didn't we would see all of it and not just over a half as we do at the moment
 

lyner

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Why is the moon visible during the day?
« Reply #9 on: 26/05/2008 10:46:31 »
it rotates around the earth every month. But it doesn't rotate around its axis at all!!!!!!!!!! try reading everything i write next time!!!!!
If it faces in a different direction throughout the month - so as to be facing us then how can it not be rotating about its axis? (Do you know what an axis is?)
Try walking around a table in the middle of the room whilst facing it all the time and without turning on an axis.
« Last Edit: 26/05/2008 10:48:44 by sophiecentaur »
 

Offline caboose17

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Why is the moon visible during the day?
« Reply #10 on: 30/05/2008 18:29:48 »
it rotates around the earth every month. But it doesn't rotate around its axis at all!!!!!!!!!! try reading everything i write next time!!!!!
If it faces in a different direction throughout the month - so as to be facing us then how can it not be rotating about its axis? (Do you know what an axis is?)
Try walking around a table in the middle of the room whilst facing it all the time and without turning on an axis.
go to this website newbielink:http://www.windows.ucar.edu/tour/link=/the_universe/uts/moon1.html&edu=high [nonactive]
and you will feel stupid
 

Offline chris

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Why is the moon visible during the day?
« Reply #11 on: 30/05/2008 18:45:43 »
Hello caboose17.

Thank you for taking part in our forum, and thank you for the link you have posted above which, if you read what that web page says, agrees with the other people above tried to tell you, and disagrees with you!

Here's a quote from the relevant part of the page (from www.windows.ucar.edu/tour/link=/the_universe/uts/moon1.html&edu=high, which you referred us to in your last post):

"Have you ever heard the term the 'far-side' of the Moon? Because of the effect on the Moon of tidal forces due to the Earth, the same side of the moon always faces the Earth. The rotation period and the orbital period of the Moon are the same. Therefore, Earth-bound observers can never see the 'far-side' of the Moon. Tidal forces cause many of the moons of our solar system to have this type of orbit."

What the bit in bold says is that the rotation period (the time it takes the moon to turn around once) is the same as the time it takes the moon to complete an orbit of the Earth - i.e. one month (about 28 days).

In other words, the moon is turning but it is doing so at a fraction of the speed that Earth turns, so it takes a whole month to do what the Earth does in a day. And because it is turning at this slow speed it ends up always showing us the same face, whilst the other side (the dark side of the moon) never points our way.

(Thanks for joining in, do come again, but please try note to be rude to other people in future, especially when they're right).

Chris

 

lyner

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Why is the moon visible during the day?
« Reply #12 on: 30/05/2008 21:48:16 »
C17
I quote from your link:
"Have you ever heard the term the 'far-side' of the Moon? Because of the effect on the Moon of tidal forces due to the Earth, the same side of the moon always faces the Earth. The rotation period and the orbital period of the Moon are the same. Therefore, Earth-bound observers can never see the 'far-side' of the Moon. Tidal forces cause many of the moons of our solar system to have this type of orbit."
Is that supposed to make me feel stupid?
 

Offline turnipsock

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Why is the moon visible during the day?
« Reply #13 on: 30/05/2008 22:32:18 »


This is a picture taken with the TSGT during the day.
 

lyner

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Why is the moon visible during the day?
« Reply #14 on: 01/06/2008 22:11:34 »
And, if you look very carefully in one of the craters, you will spot a tiny flag, waving in the breeze.  Arf Arf.
 

Kasey

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« Reply #15 on: 05/09/2010 17:50:51 »
The Moon does not rotate around the Earth.  It revolves around the Earth.  Rotation = spin.  Revolution = orbit.
 

Kasey

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« Reply #16 on: 05/09/2010 17:52:19 »
What is the greatest amount of the Moon that can be seen during the day?  Half?  More?
 

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« Reply #16 on: 05/09/2010 17:52:19 »

 

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