The annual
Perseid Meteor Shower peaks this month during the evening hours of the 12th. As
with most meteor showers the meteoroids that enter our atmosphere as
meteors, or shooting stars, come from the debris left along the orbital
path of a particular comet. This month light from the waning Moon will somewhat interfere
as it brightens the sky.
The Perseids, which owes its name to the
constellation it appears to radiate outward from, has its roots in the Comet
Swift-Tuttle, a comet with an orbital period of about 120 years. As comets,
which are often described as 'snowy dirt balls', orbit the sun their dirty
icy surface is heated by the sun and the solid ices sublimate directly into a
gas. This also releases the non-ice materials, what we refer to as the dirt in
a comet, along the orbital path the comet follows.
If the Earth's orbital path
crosses the comet's orbital path at the location of the comet debris then some
of the debris enters our atmosphere and glows brightly from frictional heat
high in the upper atmosphere.
Some leave
a glowing trail, lasting for several seconds, called a train.
