Saturday, August 15, 2009

OK What Gives? Is It Meteoroids , Meteors or Meteorites?

Hello from Columbus Ohio I am escorting my precious daughter Meghan in a pageant here but I will always have the time to upload my blog . Just wanted you to know I did Dad stuff too!
Now for most everybody out there this is a great question. Here is the odd part Those three words refer to the same exact object. Hey, as you are finding out science makes things a bit more complicated at times than absolutely necessary. For the next few minutes we are going to talk about what makes Meteors tick but first lets get rid of the three word thingy.

Meteoroids are the object. Be it from Mars, the Moon, asteroid or comet that is still outside of Earth's atmosphere. Sort of picture the "Before" shot. Now how big can they be?Well... pretty big all the way up to (what happened to the dinosaurs?) big. That was a very big rock (about 10km wide) that crashed into the Yucatan peninsula 65 million years ago. They can be as small as Dust or crumbs coming from a comet. On to Meteors. When a Meteoroid penetrates our atmosphere, heat builds up because of friction Etc.. The heat builds and the meteor( as it is called now) starts to vaporize. That's when you can see it as a streak of light against the night sky. There have been Meteors seen in broad daylight. That is one bright meteor. In the game, that is called a fireball. Picture a rock that has traveled through space, (meteoroid) has entered Earth's atmosphere then set ablaze (meteor) but it is still coming and wham it hits the ground or in this case here a car... The second it hits the earth it becomes (as if by magic) a meteorite! This car pictured has traveled the world on exhibit. Fatalities from Meteorites? Well.... in 1930 a Cow was struck and killed by a meteorite. How about this one. In 1954, a woman living in Alabama was struck and injured while taking it easy in her easy chair. I would say she had a great story to tell!

Now Let us classify Meteorites into three categories for simplicity's sake. They are Stony Meteorites, Iron Meteorites and Stony-iron Meteorites. Stony Meteorites are made out of well... stone. I know you were probably ahead of me on that one but there are little jewels inside these meteorites that tell a tale of how our solar system was formed. These little round beauties are called Chondrules. They were formed when the Solar system was cooling off. They solidified into spheres and then were accreted into larger objects. Eventually these objects were to become the asteroids we know today. Some stony meteorites have a slew of chondrules while others not so much and this is due to the way Asteroids form. If they had high heat applied while forming then chondrule will be found less often. Cooling fast resulted in many chondrules. That's one of the reasons why stony meteorites are so varied.

Iron meteorites are just that and more. They include combinations of iron, nickle and cobalt with iron being the lions share of the mixture. They have some mass to them let me tell you. An iron meteorite hit Winslow Arizona some 25-50,000 years ago. That left a big impression on the area! A huge crater resulted 750 feet deep with a circumference of 2.4 miles. It is about 550 feet deep now. This particular Meteorite vaporized almost completely when it hit the ground. There were remnants of the event scattered for miles with this fine iron spherical dust everywhere (Vaporized). So we got a huge crater and no meteorite. Well try this one on if you go to Africa you will get to see the worlds biggest iron meteorite. It sets in a field with no Crater to be found. Now Steve ole buddy How can that be? I'm pretty sure no one moved it as it goes about 60 to 70 tons. Have you ever skipped a stone across the creek? Scientists now believe that's what happened. The meteor came in at a low angle and skipped along until it came to rest in a farmers field in Hoba.You just never know what you are going to run into when it comes to meteorites. That kind of sends us into the next class of meteorites. Stony iron meteorites are some of the prettiest objects you will ever see. Iron with crystals buried in it. Does it get any better than that? They are so beautiful to look at. These are pallasites and they are stunners.

Alright Steve I am sold! Point me toward the meteorite field. To be honest meteors fall everywhere and pretty evenly but If you want to find them, go where the terrain looks least like Meteorites. Can you guess a really COOL place? Antarctica is a great place to look as the Meteors sit on top of the ice. Wind erodes the snow and leave the stones for the harvesting. OK maybe you don't have a hankering to freeze your tukus off looking for off world gravel. in that case try the Sahara desert white to light brown sand. When a blackened meteorite hits the that sandy floor it kind of sticks out like a sore thumb.But again you might not have the cash to go to Africa. Have you tried Kansas? yep that could be a little better. Just look in the freshly turned over fields and hey you just might find a meteorite to hand down to your kids.

Clear skies and great seeing too,

Steve T.

1 comment:

  1. We get great meteor activity in Scandinavia where I live. The Quadrantids was the very first meteor shower of the year,here in Finland as well as and one of the strongest. The Quadrantids produce extraordinary fireballs, meteors that are exceptionally bright and at times produce persistent trails/trains. This annual celestial event is active from January 1st through January 10th and peaks on January 4th. The peak is defined as the moment of maximum activity and the most meteors can be seen by observers.