Readying for shooting stars and meteor showers

It’s good that shooting stars are not actually stars. The Earth wouldn’t exist if stars constantly whizzed through the atmosphere.

Map of the Perseid Meteor Shower. Photos courtesy of NASA

The dazzling streaks of light across the dark sky are actually fragments of comets, asteroids and other interplanetary objects.

On the nights of Aug.11 and Aug. 12 the Perseid Meteor Shower reaches its climax.

A meteor shower is the predictable time when the Earth passes through the remnant dust cloud of a comet. Meteor showers can last for a few weeks, although they peak over a single night or two. As a comet orbits the sun, its icy body vaporizes, creating the iconic tail of the comet. The tail leaves behind a cloud of debris.

As the Earth passes through the cloud particles, known as meteoroids and usually smaller than a pebble, are forced to interact with the Earth’s atmosphere. Meteors are like bugs on the Earth’s windshield!

The word meteor comes from the Greek meteōros meaning “high in the sky.” Hence, we have “meteorology,” the science of weather, often confused as the science of meteors. Meteoroids are interplanetary objects, smaller than an asteroid and larger than an atom. When they enter the Earth’s atmosphere, meteoroids are traveling about 45,000 miles per hour! This speed and the change in density from space to atmosphere cause a tremendous amount of friction. The meteoroid glows from the heat, becoming a meteor. Most meteors burn up in the atmosphere, although larger fragments can survive to become a meteorite when reaching the ground.

Meteor showers derive their names from the constellation that their meteors radiate from. The Perseids radiate from Perseus (October Orionids from Orion; November Leonids from Leo and December Geminids from Gemini.)

All meteors in a shower will not start in the constellation but their tail will point back towards the radiant. Meteors that do not point back to the constellation are called sporadics.

Meteor showers are best viewed from a dark sky location with clear horizons. The best time to view a meteor shower is usually after midnight, although the moon’s phase is taken into consideration because dark skies are necessary.

The Perseids are a reliable shower each year with between 50 to100 meteors per hour under ideal circumstances. This year, a crescent moon will rise after midnight, dampening the show in the early morning.

 

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