June 30 – Ka-Boom!

Today’s factismal: It is World Meteor Day. Go out tonight and look for meteors!

The world of meteors is a confusing one to the uninitiated. We speak of meteors and meteorites and falls and finds and astroblemes and bolides and expect everyone else to know what we mean [1] (and we don’t call it “meteorology” because that was already taken; instead, it is called meteorics). But one part of that world is easily understood – today is World Meteor Day because one of the most famous events ever happened 105 years ago today.

Devastation at Tunguska (Image courtesy the Leonid Kulik Expedition)

Devastation at Tunguska
(Image courtesy the Leonid Kulik Expedition)

Known as the Tunguska event, this was the largest meteorite impact for at least a million years. What happened was that a chunk of rock roughly the twice as big as a house fell into the Earth’s atmosphere over Tunguska, Russia. As it went deeper into the atmosphere, the pressure caused the rock to break into pieces and burst in the air (what meteoricists cleverly call an “air burster”) in a massive explosion that was 1,000 times stronger than the bomb dropped on Hiroshima. The explosion sent a burst of heat so great that a man 40 miles away felt as if his clothing had caught fire, and a clap of pressure so large that it leveled trees over 830 square miles! To put this into scale, the recent meteorite explosion over Russia was only 1/30th as powerful.

But why did the Tunguska event happen? It turns out that we don’t know. Because it was an air burster and because it was nearly two decades before anyone went to investigate the event, there is very little hard data about it. And without hard data, we can’t make and test hypotheses. And that’s where you come in…

The folks at NASA have put together a Meteor Counter app. All you have to do is lie back, watch the sky and tap the app whenever you see a meteor. Your data will automatically be sent to the researchers, who will use it to help us learn more about meteors and any dangers they might present.
http://science.nasa.gov/science-news/science-at-nasa/2011/13dec_meteorcounter/

[1] For those who like to keep their pedantry straight, here are the distinctions: A meteor is the bit of light streaking across the sky caused by the rock passing through the Earth’s atmosphere.Once it hits the ground, the meteor becomes a meteorite. And if the meteor is exceptionally bright, it is a bolide (also called a fireball). A fall is any meteorite that was observed as it fell to Earth; if it wasn’t seen, it is a find. And if it makes a crater, we call the crater an astrobleme or “star wound”. No go and be pedantic, my padawan!

One thought on “June 30 – Ka-Boom!

  1. Pingback: September 8 – How Thai The Moon | Little facts about science

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