Peter Williams asked:
Why is the moon sometimes visible during the day?
Weíve gone to the forum for this one. Basically itís visible because when itís in the sky itís just another object being lit by the sun. So when itís in the right place we can see it.
The moon is orbiting the Earth once every 28ish days. You canít see it during the day if itís right between us and the sun because the back of it, which isnít lit up by the sun, is pointed towards us. If the moon is around 45 degrees off the sun or even 90 degrees off the sun then half of it will be lit up really quite brightly. Then the surface of the moon is about as bright as the surface of the Earth is.
Thereís no reason why you shouldnít be able to see it! As long as the moonís at 45 degrees the sunward side of the Earth and itís lit reasonably youíll be able to see it.
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? Peter Williams , Sat, 10th May 2008
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.
It is big and round and close to the earth. JimBob, Sun, 11th May 2008
A cheese in flight? lyner, Sun, 11th May 2008
here is a little flash animation I wrote a few years ago showing the moon orbiting the earth.
also did you know that the moon doesn't rotate on its axis, so one side is always facing earth. caboose17, Fri, 16th May 2008
Actually, it rotates once a month!!! lyner, Fri, 16th May 2008
it rotates around the earth every month. But it doesn't rotate around its axis at all!!!!!!!!!! try reading everything i write next time!!!!! caboose17, Mon, 26th May 2008
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 Soul Surfer, Mon, 26th May 2008
And, if you look very carefully in one of the craters, you will spot a tiny flag, waving in the breeze. Arf Arf. lyner, Sun, 1st Jun 2008
The Moon does not rotate around the Earth. It revolves around the Earth. Rotation = spin. Revolution = orbit. Kasey, Sun, 5th Sep 2010
What is the greatest amount of the Moon that can be seen during the day? Half? More? Kasey, Sun, 5th Sep 2010