July 31, 2014
August Perseid Meteor Shower To Share The Night Sky With A Supermoon
April Flowers for redOrbit.com - Your Universe Online
Amateur astronomers anxiously await the mid-August Perseid meteor shower every year. Typically occurring on the 11th, 12th and 13th of August, the meteor shower is one of the treats of the summertime sky.
This year, that treat is being enhanced by a supermoon.
Though this is not the only supermoon this year, it is predicted to be the biggest, and brightest, full Moon we will see this year. It should add an element of beauty to the normally spectacular shower.
Approximately every 133 years, Comet Swift Tuttle slices through the inner solar system, leaving a trail of dust and grit behind it. Each year, Earth's orbit takes us through this debris cloud. Specks of comet dust hit the atmosphere at around 140,000 mph and burn up in flashes of light. The meteor shower is called the Perseids because they seem to fly out of the constellation Perseus.
Comet Swift Tuttle was independently discovered by two American astronomers within three days of each other in 1862. Lewis Swift first saw the comet on July 16 and Horace Parnell Tuttle (a Union Naval officer) saw it on July 19. The comet is visible with large binoculars and is expected to make another appearance in our skies around August 14, 2125, according to Sally Stephens of the Astronomical Society of the Pacific.
People watching typically count more than 100 Perseids an hour, but that might not be the case this year.
The Perseid shower will peak on August 10th, the same night the Moon will become full. A normal full moon would wipe out some of the darkness needed to observe the shower, but this particular month, the moon will become full as it reaches perigee — the place in its orbit where it is closest to the Earth. The supermoon will be as much as 14 percent closer than normal, and 30 percent brighter than other full Moons this year.
"This is bad news for the Perseids," says Bill Cooke of NASA's Meteoroid Environment Office. "Lunar glare wipes out the black-velvety backdrop required to see faint meteors, and sharply reduces counts."
The news isn't all bad. The debris field that creates the meteor shower is broad, which allows sky-watchers to see the Perseids as early as late July, well before the supermoon occurs.
According to Cooke, "the Perseids are rich in fireballs as bright as Jupiter or Venus. These will be visible in spite of the glare."
Cooke and his team have been tracking fireball activity since 2008 using a network of meteor cameras distributed across the US, building a database of hundreds of events. So far, the analysis shows that the Perseid are the undisputed "fireball champions" of annual meteor showers. "We see more fireballs from Swift-Tuttle than any other parent comet," he says.
Whether your focus is the supermoon, the Perseid shower or a combination of both, it should be a beautiful time to be sky-gazing.