Solstice Moon Illusion June 16 , 2008: Sometimes you just can't
believe your eyes. This week is one of those times. On Wednesday
night, June 18th, step outside at sunset and look around. You'll
see a giant form rising in the east. At first glance it looks
like the full Moon. It has craters and seas and the face of a
man, but this "moon" is strangely inflated. It's huge! You've
just experienced the Moon Illusion. Above: The full Moon beams
through trees in Manchester, Maryland. Credit: Edmund E.
Kasaitis. Copyright 2008; all rights reserved. There's no better
time to see it. The full Moon of June 18th is a "solstice moon",
coming only two days before the beginning of northern summer.
This is significant because the sun and full Moon are like kids
on a see-saw; when one is high, the other is low. This week's
high solstice sun gives us a low, horizon-hugging Moon and a
strong Moon Illusion. Sky watchers have known for thousands of
years that low-hanging moons look unnaturally big. At first,
astronomers thought t