Want to see something amazing this weekend? Just look up at the sky.
Observers have dubbed it a “supermoon.” On Saturday the moon will be bigger and brighter than it has been for 20 years. As it orbits the earth in an elliptical fashion, one side of the moon (the perigee) will be about 50,000 km closer to the Earth than the other side, known as the apogee. But you’ll only note the difference if you spot it when it’s in the horizon, hanging low. Astronomers and psychologists can’t explain why, but when it’s viewed through foreground objects, like trees or buildings, illusion fuses with reality and the perceived size is stunning. The perigee moon will appear 14% larger and 30% brighter. Scientists call it the “moon illusion.”
(More on TIME.com: See the 40th anniversary of the moon landing)
During this phase the moon causes tide levels to rise. This has led to the rumor that the moon’s movements triggered the Japanese tsunami. But scientists assure that the earthquake, which killed thousands, was caused by the Pacific plate, situated deep underneath Japan. And according to NASA, tide waves are only usually pushed up a few inches.
What the moon does signify is that now, worms will start coming out and the robins will return. That explains why they call it the “worm moon,” and it’s a sign that spring is on its way.
(More on TIME.com: See pictures of Apollo 11’s liftoff)