Why is the moon enormous tonight 12-12-08?

Answer 1

The Moon is EXACTLY THE SAME SIZE tonight as it has been for hundreds of thousands of years. Hundreds of millions of years.

However, it does LOOK bigger tonight, because of a curious alignment of the Moon's orbit.

The Moon, like all the planets in the solar system, does not travel in a circular orbit, but in an ellipse; an oval. The difference isn't big, but it is sometimes noticeable. And the Moon's elliptical orbit "wobbles" just a little, so that perigee, the closest point to Earth in the Moon's orbit, doesn't correspond to a full moon very often. Tonight it does; the full Moon, as close as it normally gets.

It's even better. The Moon's orbit is tilted to the ecliptic, which means that sometimes the Moon is south of the equator and sometimes it is north. Today, it is about as far north as we usually see it, which means that it is just a tiny bit closer to us in the northern hemisphere.

So if we add it all up, the Moon is full, high in the sky, and closer than usual; these things only come together every 10 years or so. The Moon tonight appears about 15% larger than average, and almost a third brighter than normal. Enjoy the show!

Check out Spaceweather.com every day for interesting information about what's up, up there!