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- In an ancient Maori legend, Tane gave his father Rangi
a basket of jewels to wear. Tane represents man and his father Rangi the
sky. The gift basket is long and shiny and appears as a strip of stars
which we call the Milky Way (because of its milky white appearance). But
in Maori tradition, the stars inside the basket are more like a family.
Its restless members keep jostling one another so that, once in a while,
one of them falls out and we see a shooting star.
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- Near-Earth asteroid Mathilde
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- Most shooting stars are burning debris from the tails
of comets, but some are large fiery rocks leaving short trails of ionized
particles. The rocks range in scale from microns to the size of Texas.
They are better known as asteroids.
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- Sometimes spherical, other times misshapen, asteroids
are always preceded by a bad reputation. They roam the solar system like
Quasimodo roamed Notre Dame, tolling the bells for all to enjoy but scaring
anyone watching. There may be up to a million Quasimodos roaming the lonely
corridor of space between Mars and Jupiter, and sometimes raising a ruckus
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- Once in a while a pair collides and one or more are
thrown into an orbit that brings them within range of Earth's grip. As
soon as they enter the atmosphere, friction turns our sky into a public
stake where the asteroids burn before our delighted eyes.
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- Asteroids are the misunderstood freaks of the solar system.
The position of planets with respect to the sun follows a simple mathematical
sequence called Bode's Law. The law fails between Mars and Jupiter where
it places a nonexistent planet. The discovery of the first asteroid there
was thought to confirm this sequence.
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- Chicxulub Crater in the Gulf of Mexico
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- But then another asteroid was discovered there, and thousands
followed. Asteroids were then thought to be the remnants of the planet
which might have existed between Mars and Jupiter, and somehow exploded
or disintegrated.
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- For this reason and because of their range in size, asteroids
are also called minor planets. Given their orbits, however, it would take
five exploded planets to create the entire asteroid belt. A better theory
is that asteroids are fragments from the original nebula that created
the solar system.
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- There must have been many asteroids. The craters on the
moon and Mercury bear witness to heavy bombardment. On Earth most asteroids
fall into the oceans and land scars are eroded by wind and water. Nevertheless,
Arizona's Meteor Crater " a hole one mile in diameter " is a
reminder that Earth is not immune to large extraterrestrial impacts.
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- Perhaps Quasimodo deserves his reputation after all.
One or more large asteroids have been blamed for the extinction of the
dinosaurs. A large enough impact may have raised enough dust to shield
Earth from precious sunlight, killing all plant life and subsequently
the dinosaurs that depended on it for food. Small mammals would have survived
by eating the reptiles' carcasses.
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- <http://foxnews.com/scitech/features/perelmuter/070899_quiz.sml
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- An enormous crater between 110 and 180 miles wide has
indeed been uncovered under mud and sediment in Mexico's Yucatan peninsula.
Chicxulub crater dates back to the correct era but some studies suggest
the timing is too far off to be responsible for the dinosaurs' mass extinction.
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- Another theory speculates volcanic activity led to a
greenhouse effect selectively decimating species unable to adapt to the
environmental shifts. So what did the dinosaurs in?
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- Earthlings witnessed comet Shoemaker-Levy break up and
fall on Jupiter, a cosmic hair away from Earth. Comets, not asteroids,
may be the culprit.
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- Asteroids are the simplest members of our cosmic family
but also the least well interpreted. Are they the messengers of doom or
the ushers of life?
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- Perhaps a Neanderthal made a wish upon a very special
shooting star.
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- <mailto:scitech@newsdigital.com
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