When the full moon rises tomorrow night, you may get a glimpse of something very rare: A supermoon. The supermoon is the result of a change in the moon’s position, making the moon appear 15% larger and 20% brighter than usual.
Here’s why it happens:
The moon is round, but its orbit is not: it’s ovoid. When it’s closer to earth it’s at Perigee, and when it’s further away from Earth, at Apogee. And the moon’s orbit varies in size as well. Tomorrow, it will be at the position closest to earth: 221,566 miles away. It hasn’t been this close since 1993. And there hasn’t been a supermoon for 18 years.
So how do you avoid missing this rare lunar event?
Apparently, the supermoon will be visible from anywhere you can normally see the moon. Some Astronomers suggest finding a place where you can see the sun setting and the moon rising at the same time for an extra dramatic effect. The moon will look biggest when seen against the horizon, or peeking out from behind the silhouette of a tree, building or other object in the foreground. This is known as the “moon illusion”
And in case you’re wondering, the theory that the supermoon is somehow involved in the recent natural disasters in Japan has been dismissed by scientists: “…the small differences in the tidal forces exerted by the moon (and sun) are not enough to fundamentally overcome the much larger forces within the planet due to convection (and other aspects of the internal energy balance that drives plate tectonics),” said NASA scientist Jim Garvin in a statement.
If Daylight Savings’ Time has your kids in bed before the moon rises, don’t be too sad about them missing the supermoon. According to Anthony Cook, astronomical observer at the Griffith Observatory in LA, the effect may be more subtle than it sounds.
“I doubt that most people will notice anything unusual about this full moon,” Cook said.