7:15 AM | *The annual Perseid meteor shower peaks late this Sunday night/ into early Monday (August 11th/12th)...the weather is looking quite favorable*
Paul Dorian
Perseid meteors appear to radiate from the constellation Perseus in the northeast sky. Credit: WSFA 12 News (Montgomery, Alabama) /NASA
Overview
The annual Perseid meteor shower began in mid-July and will continue until late August, and the peak viewing time will be during the pre-dawn hours of Monday, August 12th. This year’s peak viewing will come at a time when the moon is 50% illuminated (first quarter phase) which is halfway between the new moon and full moon. The moon will set around midnight suggesting that the best viewing conditions will indeed be in the pre-dawn hours when the sky should be at its darkest. Of course, success for viewing will largely depend on the overall lighting in given viewing area and on overall sky conditions and the weather is looking quite favorable in the Mid-Atlantic region. The Perseid meteor shower comes every August as the Earth passes through a cloud of dust that comes from Comet Swift-Tuttle as it approaches the sun.
Background on the Perseids
Every year, from around mid-July to late August, our planet Earth crosses the orbital path of Comet Swift-Tuttle, the parent of the Perseid meteor shower. Debris from this comet litters the comet’s orbit, but we don’t really get into the thick of the comet rubble until after the first week of August. Earth's gravity pulls in chunks of small rocks from Comet Swift-Tuttle comprised of iron-nickel, stone, and other minerals. These small rocks turn into bright balls of hot gas when they enter the Earth's atmosphere. As darkness falls, the meteors appear to come from the constellation Perseus, hence the name; although late in the evening, the meteors actually originate higher in the sky than the constellation.
The Perseids happen every year in the July/August time period as the Earth crosses the orbital path of Comet Swift-Tuttle. This comet takes about 133 years to orbit the sun and it last rounded the sun in the early 1990s. Credit Earthsky.org/Guy Ottewell.
It is estimated that Perseid meteoroids hit our atmosphere at about 132,000 miles per hour to produce the annual light show and this meteor shower is usually rich in “fireballs” because of the size of the parent comet. Comet Swift-Tuttle has a huge nucleus - about 26 kilometers in diameter - whereas most other comets are much smaller with nuclei only a few kilometers across. Comet Swift-Tuttle has a very eccentric – oblong – orbit that takes this comet outside the orbit of Pluto when farthest from the sun, and inside the Earth’s orbit when closest to the sun. It orbits the sun in a period of about 133 years. Every time this comet passes through the inner solar system, the sun warms and softens up the ices in the comet, causing it to release fresh comet material into its orbital stream. Typically, meteors are only the size of pebbles, some as small as a grain of sand, but Comet Swift-Tuttle produces a large number of meteoroids that are large enough to produce “fireballs”. In fact, the Perseid meteor shower is considered the “fireball champion” of all of the annual meteor showers.
A photo of Perseid meteors seen in 2019 from Macedonia. Courtesy spaceweather.com/Stojan Stojanovski
This year’s event
The Perseid meteor shower will reach a broad peak centered on the pre-dawn hours of Monday, August 12th. The moon will be in first quarter phase (50% illuminated) and will set around midnight suggesting that the best viewing conditions will be between about midnight and dawn in the northern hemisphere. There certainly can, however, be some sightings during the late evening hours of Sunday, August 11th, but pre-dawn hours are favored because this is when the Earth turns to face the incoming meteors more directly. Meteor rates can potentially reach 50-100 per hour in rural locations during the pre-dawn hours with the setting of the moon around the midnight hour.
Hopefully, skies will cooperate on the peak nights/early mornings of Sunday, Monday, and Tuesday (August 11-13) and the overall weather outlook does indeed look quite favorable from this vantage point across much of the Great Lakes, Midwest, Mid-Atlantic and Northeast US. There will be other opportunities later in the year for viewing meteor showers with the next one of note - known as the Orionids - to peak on October 20-21…that one brings about 10-20 shooting stars per hour.
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com