Super Moons and Meteors 6 Aug 2014

We are in the middle of a lunar triple-feature: Three super moons in a row. Super moons happen when the full moon’s orbit brings it closest to Earth. There was a super moon on Saturday, July 12th, the second will occur Sunday, August 10th, and the third on Tuesday, September 9th. There were three in a row last year too, so they aren’t that unusual. Still, a super moon, whether part of a triad or not, is impressive. They are about 14% larger and 30% brighter than ordinary full moons.

Luna, the moon, has long been associated, rightly or wrongly, with insanity – as in lunatic or loony. Demon-possessed people are supposed to change to blood-drinking fiends called werewolves when the moon is full. Police agencies often associate the full moon with an increase in violent crime. Couple Halloween with a full moon and you have the most frightening possibilities with goblins, bats, and witches flying across its bright face throughout the night. However, Halloween and a full moon are fairly rare. The last one was in 2001 and the next one will not be seen until 2020. Do dogs, wolves and coyotes really howl more at the full moon? Or are they just able to see spooky, unsettling shadows better then? In sharp contrast to the grim tales about our satellite, the full moon is also considered a lover’s moon, when enraptured sweethearts stroll in enamored bliss under its tranquil illumination. Or maybe that’s just another form of lunacy, but I think not. I’m a romanticist. Incidentally, one study shows that people sleep an average of 25 minutes less when the moon is full.

Full moons appear huge when they are closest to the horizon, much larger than when they are fully up in the sky. But that’s only an optical illusion. When it’s higher in the sky we don’t have buildings, trees, and hills to compare it to. Don’t believe me? The full moon will rise at 7:59 p.m. here in East Texas on August 10th. Go outside and pinch your thumb and forefinger together so the moon just fits between them. Or better yet, make two marks on the edge of a piece or paper or 3x5 card showing where the top and bottom of the moon line up. Then wait until it’s fully risen, way up in the sky, and check it again. You’ll see I was right.

A bonus this August is the Perseid Meteor Shower that will peak from August 12th-13th. The Perseids get their name from the fact that they appear to originate from the region of the constellation Perseus. Meteor showers take place when Earth passes through comet debris, in this case Comet Swift-Tuttle. The Perseid Shower is often the source of the greatest number of the more brilliant meteors called fireballs each year. Once in a while meteoric visitors produce bolides, huge fireballs that explode in the atmosphere.

Unfortunately, this year’s shower will have to compete with the full moon, so a lot of the dimmer meteors will probably be masked by the lunar brilliance. The best time to observe is after midnight since we are then passing face-on into the debris cloud, but any time will be alright. Watch the entire sky, particularly in the darker regions. In addition, don’t wait until the peak. The week before and after the peak may be rewarding and the moon won’t be quite as bright.

Meteors occur when bits of comet debris strike our atmosphere and the friction causes them to ionize and burn up. Traveling at speeds from 25,000 to 160,000 mph most meteors are caused by particles only the size of a grain of sand or smaller. But the energy burst we see leaves a brief glowing trail that can be thousands of miles long, although they appear short from our vantage point.

Once in awhile a very large piece of material streaks into the atmosphere and explodes. For example, the Chelyabinsk meteor was a near-Earth asteroid that entered Earth's atmosphere and exploded over Russia’s southern Urals on 15 February 2013 at about 76,000 feet. According to NASA and other reports, it was about 65 feet in diameter. Called a super-bolide, it released 20–30 times more energy than the atomic bomb detonated at Hiroshima, and was brighter than the sun. Some 7,200 buildings in six cities across the region were damaged by the shock wave that blew out windows and cracked walls. Witnesses said they could feel the intense heat from the blast. It may have been the largest object ever to enter earth’s atmosphere since the 1908 Tunguska event that destroyed a wide, remote, forested area of Siberia.

Even at their least spectacular, meteor showers are exciting. Take a lawn chair away from city lights and enjoy the light show.

Dr. Risk is a professor emeritus in the College of Forestry and Agriculture at Stephen F. Austin State University in Nacogdoches, Texas. Content © Paul H. Risk, Ph.D. All rights reserved, except where otherwise noted. Click to send questions, comments, or request permission for use.