Sunday, August 9, 2009

Put Up The Umbrella Stella There's Going To Be A Shower

The Annual Perseid meteor showers are upon us. There is nothing better in this world than to lay on a blanket with the love of your life staring at the sky in hopes of catching a glimpse of a meteor streak across the sky. When they turn to you and ask," Hey Honey. Just what is a meteor?" The last thing they want to hear is Uh... I dunno. It kind of ruins the moment if you know what I mean. Fear not for I am here to give you a crash course on meteors because "uh... I dunno" is a real mood killer. I just love doing public service work!!! To begin with, I am going to break down where meteors come from and then how we classify them. The one thing I am not going to do is list the 2000 different classifications of meteors and how they are broke down into chemical features. The reason is because the common Joe,will be put to sleep by all those numbers and symbols. Remember why I am telling this to you. The last thing your love wants to hear when they are cuddled up next to you is "An Octahedrite is a broad class of iron meteorites which is characterized by the presence of both Taenite and Kamacite nickle iron minerals in the crystal structure of the meteorite" Do you see what I mean?

Meteors come from three main sources, The first source to touch on are asteroids. Our Asteroid field located between Mars and Jupiter can be a violent place at times. Impacts on asteroids can and do cause chunks of debris from the asteroid to fly off and head elsewhere and sometimes that elsewhere is Earth. Asteroids are just like people in that they are all different. They can be Iron nickle rich or just a big stony rock or any mixture in between. When an iron asteroid impacts a stony one things get kind of mixed up stuff fuses together so there might be areas of a big asteroid that might exhibit all three forms because of impacts. When things were not quite cooled off during the start of our Solar system, There was a lot of bumping into one another going on quite regularly.Add to how hot the mixture got how fast it cooled and you have a real hodge-podge of stuff floating about out there. To quasi-quote an Esteemed twentieth century philosopher Forest Gump, "Asteroids are like a box of chocolates, You never know what you gonna get"

Meteors come from places you might not think of like the Moon or even Mars! Picture in your mind a pretty good sized chunk of rock headed towards the Moon. There is no atmosphere to slow it down. Additionally there is little gravity. When the moon gets thumped pretty good by an asteroid or big meteor, the ejecta (the cloud of debris) gets launched out into space. This pile of rock travels willy-nilly spreading out. As it passes by another planet (earth), the gravitational force sometimes grabs that rock and sends it plummeting to the surface of that planet. The moon is easy to get your head around sending rocks our way destined to become meteorites. Mars ? are you kidding me? Now Is a Martian meteorite a rare find? You bet it is. They are out there. Think how big of an impact you would need to shoot a rock from the surface of Mars to the surface of Earth. Now that's an impact!

Last but not least are Comets. They are the driving force behind Annual meteor showers. When a Comet has its frozen outer layers blown away as it passes our sun, the sand and rocks that were stuck in the ice are now free and travel the same path as the orbiting comet. If this comet's orbit happens to cross the orbital path of Earth, then this will lead to the debris hitting earth's atmosphere as Terra (Earth) moves on its merry way around the Sun. This diagram shows this process pretty well. That is why we have several annual meteor showers because we hit their orbit of left-overs The Comet responsible for the annual Perseid meteor shower is called Swift-Tuttle. It is named after the two people who discovered it. That will be enough to wow them for this Meteor shower. Peak is on the twelfth of August so look up and enjoy the show!!! Next week, Which is it Meteoroids, Meteors, or Meteorites? Until then,

Clear skies and great seeing too

Steve T

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