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physicsgg

Why Does a Meteor Explode in the Air?

with one comment

screenshot_2_17_13_9_16_pmLet me start our meteor discussion with a comment

Dear Russians. I am sorry so many of you were injured and sustain property damage. However, I am very thankful for your abundance of car mounted video cameras. Keep up the good work. It’s a good thing BigFoot doesn’t live in Russia or he would have totally been “outted” by now.

Also, some information about the meteor. Most of these are estimates, but they will at least give us a starting value to calculate some things. You can find many of these detailson NASA’s page for the event.

  • The meteor came in around 10:20 p.m. EST near the city Chelyabinsk.
  • The estimate energy released was 500 kilotons of TNT –
  • The object has a size (I guess diameter) around 17 meters.
  • It had a speed of around 15 km/s to 18 km/s
  • The object’s mass was around 7,000 to 10,000 tons.
  • Disintegration of the meteor took about 32 seconds. Not sure this will be used here, but oh well.
  • The meteor exploded about 15 to 25 km above the ground.
  • It had a shallow entry angle of less than 20 degrees.

I think the biggest problem with this meteor is that it is nameless (at least as far as I am aware). Can’t we just name this thing? Russian meteor event is such a boring name. How about Ruskeor? That’s not insulting to Russians, is it? I hope not. Also, I would like to call it a rock instead of a meteor. I was never fond of the whole meteoroid – meteor – meteorite classification. Oh well.

Density

Was it a rock? Was it a stony-iron like rock or mostly iron? If we assume the rock is a sphere with a radius of 8.5 meters and a mass of 6.4 x 106 kg to 9 x 106 kg, then we can calculate the density. The volume of this rock would be the volume of a sphere…..

Read more: http://www.wired.com

Written by physicsgg

February 19, 2013 at 8:00 pm

Posted in Uncategorized

One Response

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  1. michael shumik
    8:01 AM (3 hours ago)

    to Yordanis
    When this meteorite entered the atmosphere, it was traveling at approx 36000 miles per hour.
    Now consider this fact; I have a roof rack that crates a howling sound when I speed up to 100 kph. This howling sound is caused by air moving past the roof rack. I can hear this howling sound with my car windows closed. If there were sensors mounted on vehicle to sense vibrations, there would be vibrations that could be recorded from the air flowing pass the roof rack.
    Now consider an object entering the atmosphere at an extreme velocity like the meteorite. The atmospheric abrasion not only causes the meteorite to vaporize and glow brightly, but as it enters the more and more dense atmosphere, the vibrations set up by the friction of the air would not sound like a howl as my roof rack makes, it would be more like standing behind a jet engine, totally unbearable,and that would only be mild sounding comparatively. Now as the object enters further into the dense atmosphere, the sonic vibrations, through the mass become so violent, that the rock cannot take those stresses, and as a result shatters. That’s when you see a bright fireball flash as all the pieces are exposed to the at that speed quickly vaporize and burn. Being much smaller now and quickly slowed down by the air resistance, only a few little remaining pieces. That’s why after the bright explosion, you could only see a few wisps of vapor trails streaming away after the blast.
    . The sonic boom caused by this object flying at this velocity and height would be very very very loud. Just think if a jet making a sonic boom sounds like a loud thunder clap, and not only shakes windows but can shatter them, then try to multiply this by several thousand times and you get what this meteorite did. Now sometimes there are meteorites that don’t break up as they enter the atmosphere. That depends much on the composition, often rock, other times pure nickel and iron; which can stand tremendous vibration stresses; speed, angle of entry, and most likely other factors that we can only speculate when dealing with speeds obects such as these traveling through the air encounter.
    Now in closing, just consider this last thought. If a large piece of the moon, which I hear, is made of blue cheese, broke off and came hurling into our atmosphere , what a blast that would be….all the free cheese that would be available…I’d hate speculate…just a thought to consider for the future.

    michael shumik

    February 21, 2013 at 7:11 pm


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