Transcript Asteroids, meteors, meteorites

Asteroids, meteors, meteorites
Heather, Tirzah, Trinity
Number of moons
● asteroids, meteors, and meteorites have
around 1 moon in all.
Periods of rotation and revolution
• The periods and revolution of our topic is
around 1.88 and 11.86 earth years.
Location and reference to the Sun
Physical properties
• Meteors have a variety of physical properties. Some are icy, others dusty
clumps and still others are dense and crystalline. The ones that survive
the plunge to Earth are meteorites and are typically dense and can be
rock, metal or crystalline in structure.
• Asteroids are commonly classified into types according
to their spectra. Among these types are type C, type S,
and type M. Type C asteroids are extremely dark and
comprise more than 75% of all asteroids. Type S
asteroids are relatively light asteroids composed of
metallic nickel-iron and make up 17% of all asteroids.
Most of the other asteroids are type M, which are
bright asteroids composed of pure nickel-iron. There
are a few other rare types of asteroids.
• Meteorites are basically the same thing as meteors.
Extra info
• Meteorites vary in size and, fortunately, most
of them are small.
• meteors are usually larger than those left
behind by comets and are more likely to
become meteorites by striking the Earth.
• Asteroids, which are sometimes referred to
as minor planets, are rocky, metallic bodies
that revolve around the Sun, usually in a
region known as the Asteroid Belt.
History of asteroids
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1950 -- Immanuel Velikovsky publishes "Worlds in Collision" (see bibliography), a pseudoscientific
warning about impact hazards. In equal parts bogus and frightening, Velikovsky casts the entire
field of impact studies into disrepute.
1980 -- Spacewatch program starts at the University of Arizona, intent on cataloging asteroids. The
goal is to get a statistical picture of orbiting rocks anywhere in the solar system.
1980 -- Physicist Luis Alvarez and his team blames the dinosaur extinction on the environmental
havoc of a collision. The resulting firestorm and a global soot and dust cloud, they argue, cooled the
planet enough to make the dinos long for a package vacation in Cancun. Many scientists, including
renowned comet hunters, smirk in their beer about this ridiculous notion, which only gains
acceptance after a 180-kilometer wide crater is discovered north of the Yucatan.
1994 -- Comet Shoemaker-Levy 9 breaks apart, then smashes into Jupiter under the watchful eye of
dozens of telescopes. The resulting zone of chaos is estimated to be as large as the Earth and lends
urgency to the search for asteroids and comets. "Shoemaker-Levy was a turning point," says Benny
Peiser, an anthropologist at Liverpool John Moore's University at the 2000 meeting of the American
Association for the Advancement of Science in Washington, D.C. In the course of presenting results
of the computer simulation on asteroid impacts, Peiser adds, "If it can happen in front of your nose
-- practically in your backyard -- it can also happen on Earth."
1998 -- Astronomers announce that an asteroid may be on a collision course for Earth. The warning
is quickly withdrawn after further observations.
History of meteors
• Throughout history, meteors and meteorites have had
an enormous impact on people on Earth, on events on
Earth, and even the Earth itself. First, before this
historical account begins, we need to have Meteors
101, how to tell the difference between meteors in all
their forms. A meteoroid is a rock in space. They can be
anywhere from the size of a grain of sand to the size of
a house and much larger. A meteor is a meteoroid that
has begun burning up in the atmosphere (also known
as a shooting star). A meteorite is a meteor that did not
burn completely in the atmosphere and has landed on
Earth. A very large meteoroid is also known as an
asteroid.
History of meteorites
• Throughout the ages, meteorites were venerated
as sacred objects by different cultures and
ancient civilizations. The spectacular fall of a
meteorite, accompanied by light and sound
phenomena, such as falling stars, smoke, thunder,
and sonic booms, has always kindled the human
imagination, evoking fear and awe in everyone
who witnesses such an event. For obvious
reasons, the remnants of these incidents, the
actual meteorites, were often kept as sacred
stones or objects of power. They were worshiped,
and used in their respective religious ceremonies.
Has someone or something ever been
to your topic?
• 11 comets and asteroids have been explored by spacecraft so far, as
follows: ICE flyby of Comet Giacobini-Zinner. Multiple flyby missions
to Comet Halley. Giotto (retarget) to Comet Grigg-Skellerup. Galileo
flybys of asteroids Gaspra and Ida (and Ida satellite Dactyl). NEARShoemaker flyby of asteroid Mathilde on the way to orbit and land
on Eros. DS-1 flybys of asteroid Braille and Comet Borrelly. Stardust
flyby of asteroid Annefrank and recent sample collection from
Comet Wild 2. For future we can expect: Hayabusa (MUSES-C) to
asteroid Itokawa, Rosetta to Comet Churyumov-Gerasmenko, Deep
Impact to Comet Tempel 1, and Dawn to orbit asteroids Vesta and
Ceres.
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Read more about Asteroids l Asteroid facts, pictures and
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