Perseids
Prolific meteor shower from comet Swift–Tuttle, visible mid-July to late August.
The Perseids are a major meteor shower linked to Comet Swift–Tuttle, visible each year from around mid-July through late August. They get their name because the meteors seem to radiate from the direction of the constellation Perseus—though the radiant actually sits near the borders of Cassiopeia and Camelopardalis. The term "Perseids" comes from Greek mythology, referring to the sons of Perseus.
The debris that creates the shower is known as the Perseid cloud, which follows the orbit of Comet Swift–Tuttle. This cloud is made up of particles the comet has shed during its 133-year orbit. Most of these particles have been drifting in the cloud for roughly a thousand years. A younger filament of dust, pulled off the comet in 1865, can produce a small early peak the day before the main shower. Near Earth, the cloud spans about 0.1 astronomical units across and 0.8 AU along Earth’s orbit, shaped by yearly gravitational interactions with our planet.
The shower begins in mid-July, with peak activity falling between August 9 and 14, depending on where Earth passes through the stream. At its peak, observers can see 60 or more meteors per hour. While the meteors appear across the entire sky, the radiant in Perseus means they are best seen from the Northern Hemisphere. As with most meteor showers, the highest visible rates occur in the pre-dawn hours, because Earth’s forward motion sweeps up more meteoroids between local midnight and noon. Many meteors arrive during daylight and go unseen, but some appear before midnight, grazing the atmosphere and creating long, bright trails or fireballs. Most Perseids burn up above 80 kilometers (50 miles). The largest Perseid meteoroids can weigh up to 7 kilograms (15 pounds).
Some Catholics call the Perseids the "tears of Saint Lawrence," said to hang in the sky and return each year on August 10, the date of his martyrdom in 258 AD. According to legend, Saint Lawrence was burned alive on a gridiron, and the shooting stars are the sparks of his death. The story also says that on the night of August 9–10, cooled embers—called the "coal of Saint Lawrence"—appear in the ground under plants. This Christian tradition replaced older pagan festivals, helped by the similarity between the Latin name Laurentius and the goddess Acca Larentia, a fertility deity celebrated in summer alongside Priapus.
Quick Facts
- Pronounce
- ˈ · p · ɜr · s · i · . · ə · d · z
- Date
- AD 36 (first record)
- Parent
- Comet Swift–Tuttle
- Constellation
- Perseus and Cassiopeia / (near HD 19557)
- Ra
- 03 · 13
- Dec
- +58
- Month
- July 14 – September 1
- Peak
- August 13
- Velocity
- 58.8
- Zhr
- 100
Facts from the source article.
Lore & Background
The stream of debris, called the Perseid cloud, stretches along the orbit of comet Swift–Tuttle and consists of particles ejected by the comet on its 133-year orbit. Most particles have been part of the cloud for around a thousand years, though a relatively young filament of dust pulled off the comet in 1865 can cause an early mini-peak the day before the maximum shower. The cloud's dimensions near Earth are estimated at about 0.1 AU across and 0.8 AU along Earth's orbit, spread by annual interactions with Earth's gravity.
Some Catholics refer to the Perseids as the 'tears of Saint Lawrence,' returning to Earth once a year on August 10, the date of his martyrdom in 258 AD. The saint is said to have been burned alive on a gridiron, and the folk legend claims the shooting stars are sparks of his martyrdom. The transition from pagan festivals was facilitated by the phonetic assonance of Laurentius with Acca Larentia, a fertility goddess; among the Romans, the trails were believed to represent the benevolent rain of Priapus' seed.
In 1836, Adolphe Quetelet noted a greater frequency of these meteors in August and predicted a peak on August 10, confirmed by other astronomers in 1837. In 1866, Giovanni Virginio Schiaparelli discovered the link between meteor showers and comets. In 1992, comet Swift–Tuttle returned, producing strong Perseid outbursts in 1991, 1992, and 1993. Finnish astronomer Esko Lyytinen calculated that Earth could enter an extra thick debris field in 2028, possibly producing a meteor storm on the night of August 11–12, 2028, with a peak rate of at least 1,000 meteors per hour.
Reader's Guide
The Perseids are notable as one of the most prolific meteor showers, associated with the well-known comet Swift–Tuttle. Their visibility from mid-July to late August and peak in early August make them a regular celestial event for Northern Hemisphere observers. The shower's historical significance includes its Christianization as the 'tears of Saint Lawrence,' replacing earlier Roman associations with fertility rites involving Priapus and Acca Larentia. The scientific understanding of the Perseids advanced through the work of Adolphe Quetelet, who predicted their peak in the 1830s, and Giovanni Virginio Schiaparelli, who linked them to comets in 1866. The return of comet Swift–Tuttle in 1992 produced notable outbursts, and calculations by Esko Lyytinen suggest a potential meteor storm in 2028. The Perseids have also entered popular culture, appearing in Thomas Pynchon's novel Against the Day, the TV series Curious George, and John Denver's song 'Rocky Mountain High.' Their legacy lies in their consistent annual display, historical and cultural associations, and role in advancing the understanding of meteor showers.
Did You Know?
- The Perseid cloud consists of particles ejected by comet Swift–Tuttle on its 133-year orbit.
- Most particles in the Perseid cloud have been part of it for around a thousand years.
- Finnish astronomer Esko Lyytinen calculated that Earth could enter a thick debris field in 2028, possibly producing a meteor storm with at least 1,000 meteors per hour.
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