Science Questions

Why is the moon sometimes visible during the day? Peter Williams

We’ve gone to the forum for this one.  Basically it’s visible because when it’s in the sky it’s just another object being lit by the sun.  So when it’s in the right place we can see it.

The moon is orbiting the Earth once every 28ish days.  You can’t see it during the day if it’s right between us and the sun because the back of it, which isn’t 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.

There’s no reason why you shouldn’t be able to see it!  As long as the moon’s at 45 degrees the sunward side of the Earth and it’s lit reasonably you’ll be able to see it.

June 2008