SATURDAY: Extreme Supermoon

This Saturday the moon makes its closest approach to Earth in 18 years in what astronomers call an "extreme supermoon."

If no clouds get in the way, it should be a great night for stargazers. But the moon, which will appear about 10 to 15 percent larger than normal, could create abnormally high tides from Friday through Sunday, experts say. And that could mean beach erosion and minor flooding along the shoreline. "The tides are definitely going to be higher, not only in Florida, but worldwide," said astronomer Arnold Pearlstein. The best time to view the moon will be at sunset — about 7 p.m. — on Saturday, when it will be closest to the horizon and should look "huge and orangey," Pearlstein said.

There's a moon in the sky (called the supermoon.)