WRAL WeatherCenter Blog

Super moon looms Saturday

Posted May 4, 2012 9:06 a.m. EDT
Updated May 4, 2012 6:00 p.m. EDT

On Saturday night, the moon will appear about 15 percent bigger and 30 percent brighter than other full moons this year. Scientists call the moon on this date the "perigee moon" but most simply call it a "super moon." But the moon hasn't grown in size, it's only gotten closer.

This happens because the moon's orbit is more of an oval than a circle. This brings the moon closer the Earth (perigee) and further (apogee) twice a year. When that perigee moon coincides with a full moon, it's known as a super full moon.

15 percent probably isn't enough for you to notice the difference when the moon is overhead but for the most dramatic view, look to the east after moonrise around 8 p.m. When viewed near the horizon, the moon will seem even bigger due to the visual cues your brain gets from trees, houses and other objects on the horizon.

This particular super moon has particularly good timing. It reaches that point of perigee at 11:34 pm EDT Saturday night. One minute later the Earth, Sun and Moon will lineup illuminating the face of the moon 100 percent. The timing doesn't get much better than that.

Tony Rice is a volunteer in the NASA/JPL Solar System Ambassador program and software engineer at Cisco Systems. You can follow him on twitter @rtphokie.