Even if you're not a big astronomy buff, you might notice something a little different about the moon tonight if you happen to be outside. Tonight is the first of three "supermoons" that will occur this summer, the other two are to follow in August and September. Supermoons are much brighter than ordinary full moons and occur once every 13 months and 18 days.

Moonrise Time: the Moon will rise over North America at approximately 7:30 pm local time.

Moonset Time: the Moon will set over North America at approximately 5:50 am local time, Sunday, July 13th. 

But what is a supermoon? According to the LA Times, a supermoon--also known as a perigee moon--takes place when the moon happens to be full at the same time it is closest to the Earth. This is possible because the moon's orbit around the Earth is elliptical, and not a perfect circle. The closest point in the moon's orbit is known as "perigee," hence "perigee moon" or supermoon, as it's come to be known. When the moon is at its perigee, it is about 31,000 miles closer to Earth than its farthest point (or "apogee"). 

Tonight (and also on August 10th and September 9th) the moon will look like it's 14% larger and 30% brighter than a typical full moon. The best time to get the maximum effect is when the moon is near either horizon. That's because of what is known as the "moon effect," which causes the moon to appear larger than it is to observers. Astronomers are still unsure what exactly causes the moon effect. Whatever the reason, it should be quite a spectacle. So if you're outside tonight, don't forget to look up and catch a truly amazing site.