The Discovery of Comet Swift-Tuttle (109P)
(1820 – 1913)
Lewis Swift, by his own account, became interested in astronomy after seeing the Great Comet of 1843 while on his way to school in Clarkson, New York.
Nearly twenty years later, on July 16 1862, during the height of the Civil War, Swift spotted a comet. Three days later it was spotted by another American, this one a Union Naval officer, named Horace Parnell Tuttle who continued to make astronomical observations during the War. The comet became known as 109P/Swift–Tuttle.
Over the course of his life, both Swift and Tuttle discovered several comets and were highly decorated astronomers. Swift alone is credited with the discovery or co-discovery of 11P/Tempel-Swift-LINEAR, 64P/Swift-Gehrels, C/1877 G2, C/1878 N1, C/1879 M1, C/1881 J1, C 1881 W1, C/1892 E1, D/1895 Q1, C/1896 G1, C/1899 E1, and Comet Brooks-Swift (C/1883 D1).
Additional information about Comet Swift-Tuttle (109P)
When the Swift-Tuttle Comet (109P) was named in 1862 it soon after had a magnitude of 2, meaning it was easily visible to the naked eye. The tail, at its largest, spanned 25 to 30° of night sky.
It was rediscovered, during its next return to the inner solar system in 1992, by Japanese Tsuruhiko Kiuchi.
Swift-Tuttle orbits through our solar system with 113.4° eccentric orbit compared to the ecliptic so it is rarely effected by the gravity of planets.
Comet Swift-Tuttle’s dust and debris is responsible for a meteor shower called the Perseids. This can be one of the most stunning meteor showers of the year. Its reaches its peak between August 9th and 14th. By definition, the meteors appear to radiate from the constellation Perseus. In 2013, the Perseids peaks on August 12th and 13th. NASA calls the Perseids "The Fireball Champion", because it produces more fireballs than any other meteor shower. This is due to the proximity Swift-Tuttle passed from Earth during its most recent pass and the speed which the dust and debris enters our atmosphere--132,000 miles per hour. Peak times for the fireballs are from 10:30 pm to 4:30 am on August 11 and 12, 2013. The number of meteors, however, is expected to peak just before sunrise.
NASA will host a live broadcast of the Perseids from August 10-12, 2013. Bill Cooke, head of NASA’s Meteoroid Environment Office, will answer questions live online from 10 pm to 2 am. More information can be found on http://www.nasa.gov/connect/chat/perseids_2013.html#.Uf7koJXiMQJ.
Orbital Period and Comet Swift-Tuttle's Next Visit
Comet 109P/Swift-Tuttle on December 15, 1992. Credit: Copyright © 1992 by H. Mikuz (Crni Vrh Observatory, Slovenia)
Comet Swift-Tuttle orbits through the solar system once every 134 years. It spends most of its time in the Kuiper Belt.
In 1992, Swift-Tuttle’s closest pass to Earth was miscalculated by seventeen days. In 2126, when the comet makes its next closest pass, if the current calculation of the orbit is off by only fifteen days it could strike the Earth or Moon.
Oh, one small detail—Comet Swift Tuttle’s nucleus is 16.7 miles (27 km) in diameter. To put that in perspective, the comet or asteroid that hit Earth sixty-five million years ago is estimated to have been 6.2 miles (10 km) in diameter. Swift-Tuttle would have almost twenty times the energy of the impact that helped take out the dinosaurs. Thankfully, or hopefully, astronomers Don Yeomans and Brian Marsden double-checked the revised calculations and confirmed there’s no threat to Earth from Swift-Tuttle for at least the next 2000 years.
During its perihelion in 4479 CE, there is currently a 1 in 1,000,000 chance Swift-Tuttle will hit Earth or the Moon.