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WHAT IS A METEOR?


To refresh on "meteor terminology," let us quickly review the correct word associations for the upcoming event. Of course we are all familiar with the phrase "shooting star," but thank our lucky stars that STARS do NOT randomly fall from the sky. As the point of light seems to suddenly increase in brightness and move across the sky in lightening speeds, it does indeed appear to be a star that is rapidly in motion, leaving a fiery wake behind it. But "shooting star" is merely a misnomer for the phenomenon we know today as "meteor." It is one of three "names" associated with this phenomenon:
METEOROID: an object - usually dust to grapefruit size - that remains as debris from a disintegrating comet in its wake; this meteoroid will follow in essentially the same path as the comet, and thus many times encounter the earth in periodic fashion, just like the debris from Halley's Comet comes in contact with the Earth in October as the Orionid meteor shower and again in spring as the Eta Aquarid meteors. The objects following in the path of Comet Swift-Tuttle are meteoroids until they encounter the Earth's atmosphere.
Compare the two photographs of Halley's comet following, BOTH taken simultaneously on March 14, 1986; the first one I took with a 400mm Nikkor f/3 lens and camera riding piggyback at the observatory for 20 minutes showing the dust and gas tail of the comet when near brightest; it is from this decaying material that largely comprises the tail that many of our meteoroids originate. Now look at the close-up from the European Space Agency spacecraft as it rendezvoused with Halleys on the same night; you can see the solar wind actually eating away at the comet's nucleus, release much dust and debris that can possibly eventually collide with the Earth in October or May of some year in the resulting form of "Meteors."
Leonids Leonids
METEOR: when the meteoroid and Earth intersect, the particles hit the Earth's atmosphere with such velocity (many miles per second) that they ignite from the friction and typically will burn up; only slower-moving meteors and those of larger size can survive the fiery plunge to Earth and remain somewhat intact. The phenomenon of the Swift-Tuttle meteoroids hitting and burning in the Earth's atmosphere is known as the PERSEID METEORS. The Perseids usually present the brightest of all known meteors and fly through the sky very swiftly and are bright white and yellow due in large part from this rapid clip through the air.  Many break apart slowly and present spectacular fireworks and colors as they pass a fiery and seemingly smoky trail behind.
METEORITE: any meteor which can survive this fiery plunge through the dense air of Earth and actually make it to the ground is known as a METEORITE. Many of the Perseid meteors are so fast and for the most part so small that they rarely will survive the descent, and few if any meteorites found on Earth can actually be associated to the Swift-Tuttle cloud.
Leonids
This photograph shows a very bright (magnitude -4, about the brightness of Venus) meteor, or "bolide" as it streaks across Arkansas skies in 1975; this photograph was taken with a regular 50mm camera lens at f.1.7 and focused to infinity; the camera was fixed on a tripod for this 20-minute time exposure. The shot ended as soon as I knew I had captured the meteor in my camera's field of view. Viewers are encourage to use their cameras for such shots; both 35mm and digital cameras are suitable provided that you have a TIME or BULB setting and that the lens is focused to infinity. Mounting on a tripod or piggyback on a telescope is essential. Remember that if your camera is digital or has an electronic shutter, the battery life will drain quickly during long exposures.

METEOR COLORS:
Note that the apparent COLOR of the meteor as it is burned in the atmosphere CAN be a direct indicator scientifically as to some of the chemical components of which it is composed.  The nice graphic below, courtesy of AccuWeather, shows the different colors that you might witness in a brilliant fireball and the associated KNOWN chemical compounds that can be associated with the burning of the meteor "stuff", much like chemistry lab where certain chemicals can be identifed by the "flame test" of a Bunsen Burner.

Meteor colors
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