Thursday, June 30, 2011

Meteor Day!

Meteor Day
Meteors are space dust and ice that enter the earth's atmosphere. Meteors can be as small as specks of dust. As they enter the atmosphere at high speeds, they burn up, producing light as they streak across the night sky. Sometimes, you see them streak across the sky and disappear at the horizon. Other times, they end suddenly, burning out right before your eyes.

The word “meteor” refers to the visible streak of light produced by fallen debris from space—"meteoroids." We also call these beautiful sights “shooting stars” or “falling stars.”

An explosion lit up the sky on June 30, 1908, over Siberia (the likely origin of Meteor Day). Visible for hundreds of miles, the event is attributed to a meteor and is referred to as the "Siberian Explosion." The same event is also referred to as the "Tunguska event," as the meteor is thought to have exploded over the Tunguska River.

"Detonating with an estimated power 1,000 times greater than the atomic bomb dropped over Hiroshima, the Tunguska event leveled trees over 40 kilometers away and shook the ground in a tremendous earthquake," according to NASA.

To learn more about meteors:
* Take a trip to the local science or children's museum and examine meteor rocks.
* Camp out under the stars and look for shooting stars. Check HubbleSite's Tonight's Sky for clues on what you might see.

meteorites, tektites and impactites
(image reconstruction by author)

From the printed card is the following:
About 3000 tons of material from outer space falls to Earth daily. Most of it burns up in Earth’s atmosphere as a meteor or shooting star. A piece which reaches the earth’s surface is called a meteorite. If a meteorite is large enough, its impact produces a crater. This meteorite oxide crust comes from just outside Meteor Crater near Winslow, Arizona. It was formed by the weathering of a nickel-iron meteorite which fell about 30,000 years ago.

A very large meteorite melts the rock in its crater at impact. If some of this melt is thrown from the crater into space it hardens into a glass called a tektite and then falls back to earth. This tektite from Thailand formed about 730,000 years ago.

A new theory on the origin of tektites suggests that they were part of a ring system much like the planet Saturn has that fell back to Earth thousands of years ago. This new theory provides some plausible explanations for anomalous facts regarding tektites that don’t fit well with more currently known facts of impact and molten ejecta falling back to Earth.

We were fortunate to take the kids to see the giant meteor crater in Arizona a few years ago:


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