Transcript Mav Mark 11/14/11 - Madison County Schools

Mav Mark
11/14/11
List all 8 planets in order of distance from the sun.
Comets, Asteroids,
and Meteors
Notes
Comets
• A comet orbits the sun. A comet is
made of ice, dust, and small rocky
particles. You can think of a comet as a
“dirty snowball.”
Comet Hale–
Bopp, as seen on
29 March 1997 in
Pazin, Croatia
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Comets
The brightest part of a comet is the head.
A comet’s head is made up of a nucleus
and a coma. The nucleus is the solid core
of the comet. The coma is a fuzzy outer
layer made up of clouds of gas and dust.
A comet’s tail usually consists of two
parts: an ion tail and a gas tail. Both tails
usually point away from the sun; one tail is
made of gases, and the other is made of
electrically charged particles.
Comets
• The orbit of a comet is highly elliptical,
therefore it takes a very long time for
comets to orbit the sun.
Comets
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Most comets originate in one of two regions
surrounding the solar system:
The Kuiper Belt is a doughnut-shaped
region that extends from beyond Neptune’s
orbit to about 100 times Earth’s distance
from the sun.
The Oort Cloud is a spherical region of
comets that surrounds the solar system out
to more than 1,000 times the distance
between Pluto and the sun.
Asteroids
• An asteroid is a rocky object that orbits
the sun, but is still too small to be
considered a planet.
• Most asteroids are in orbit between
Mars and Jupiter. The region of the
solar system is called the asteroid belt.
Asteroids
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Most asteroids are less than one kilometer in diameter, but
some are much larger, bringing the number of asteroids up
to over 1,000,000.
Astronomers believe that asteroids are leftover pieces of
rock from the early solar system.
The total mass of the asteroid belt is estimated to be just
¼ of the mass of the Luna. The four largest objects,
Ceres, Vesta, Pallas, and Hygiea, account for half of the
belt's total mass, with almost one-third accounted for by
Ceres alone.
Ceres is now one of our five dwarf planets.
Ceres, Luna, and Earth
Number 1 is Ceres, 4 is Vesta, 2 is Pallas, and 10 is
Hygeia in the asteroid belt, compared to our moon in
the background.
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Asteroids
Occasionally, asteroids can leave the asteroid belt
due to collision or gravitational disturbances from
Mars or Jupiter.
These loose asteroids can travel around the sun in
much more elliptical orbits, which can put then in
the paths of planets.
These impacts have been known to impact Earth
every 50 million years or so. The last major impact
was the K-T (Cretaceous-Tertiary) impact that led
to the extinction of the dinosaurs 65 million years
ago.
Meteors
• A meteoroid is a chunk of rock or dust in space.
• Some meteoroids from when asteroids crash
into each other. Other meteoroids from when
comets break apart.
• Meteoroids can enter Earth’s atmosphere.
When one does, friction between the meteoroid
and the air produces a streak of light in the sky.
A meteor is a streak of light in the night sky
produced by a meteoroid. Think: meteor
shower.
Meteors
• Most meteoroids burn up completely in
that atmosphere, turning into nothing
but the dust you see floating in front of
bright lights.
• However, some will strike Earth’s
surface. Meteoroids that hit the ground
(or a house, car, person, animal, etc.)
are called meteorites.
Possible life-forms on a meteorite in Antarctica
Largest meteorite ever found in America
Mile-wide crater in Arizona
Discovered meteorites can usually be sold to
museums and science labs for tens to thousands of
dollars each.