Meteors

1
Meteors!
Meteoron Greek for thing in the sky meteor -
objects that fall through and burn up in the
Earths atmosphere. Most are small grains of rock
or metal. They produce streaks of light called
shooting or falling stars. meteorite a meteor
that hits the earth meteoroid a chunk of rock
or dust in space
2
meteor shower - When many meteors fall through
the atmosphere in a short time. Meteor showers
are formed mainly by comets that come too close
to the Sun. Heat from the Sun causes dust and
rock to break off the comets nucleus. This
continues to move along the comets orbital path.
If Earths orbit crosses this path, the dust
particles burn up in the atmosphere to produce a
meteor shower. Starry night video clip
3
http//antwrp.gsfc.nasa.gov/apod/ap080911.html
4
http//antwrp.gsfc.nasa.gov/apod/ap080103.html
5
http//antwrp.gsfc.nasa.gov/apod/ap061119.html
The Peekskill meteor of 1992 was captured on 16
independent videos and then struck a car.
Documented as brighter than the full Moon, the
spectacular fireball crossed parts of several US
states during its 40 seconds of glory before
landing in Peekskill, New York. The resulting
meteorite, pictured here, is composed of dense
rock and has the size and mass of an extremely
heavy bowling ball. If you are lucky enough to
find a meteorite just after impact, do not pick
it up -- parts of it are likely to be either very
hot or very cold.
6
Asteroids!
Asteroids Rocky objects revolving around the sun
that are too small and numerous to be considered
planets. Asteroid belt The region of the solar
system, between the orbits of Mars and Jupiter,
where many asteroids are found. It is currently
thought that the asteroid belt is material that
did not form a planet because of Jupiters strong
gravity.
7
Galileo image of Gaspra
www.windows.ucar.edu
8
Comets!
Comet a loose collection of ice, dust, and
small rocky particles, typically with a long,
narrow orbit. A dirty snow ball! Comet means
hairy star in Latin! Most comets are hidden
from us in the Kuiper belt or Oort
cloud. Periodic comets ones that keep returning
to the earth on a regular basis probably come
from the Kuiper belt.
9
Non-periodic comets - comets that swing around
the Sun once and are flung off into space -
probably come from the Oort cloud. There are 2
parts to a comet, the head and the tail. The head
is made up of the coma and the nucleus. As a
comet approaches the sun, the energy turns the
ice into gas releasing gas and dust. Some of
this streams outward, forming a tail. There can
be a gas tail and a dust tail. The gas tail
always points away from the sun.
http//www.windows.ucar.edu/tour/link/comets/come
t_model_interactive.html
10
Comet Hale-Bopp's blue ion tail, consisting of
ions from the comet's nucleus, is pushed out by
the solar wind. The white dust tail is composed
of larger particles of dust from the nucleus
driven by the pressure of sunlight, that orbit
behind the comet. Observations showed that Comet
Hale-Bopp's nucleus spins about once every 12
hours.
http//antwrp.gsfc.nasa.gov/apod/ap080302.html
11
Since brightening unexpectedly by nearly one
million fold in late October, the last three
months have found the coma of Comet 17P/Holmes
both expanding and fading. This spectacular
composite image shows how the coma and tail of
Comet Holmes have changed. Due to Earth's
changing vantage point, Comet Holmes, out beyond
the orbit of Mars, was seen in November nearly
head-on, but in recent months is seen more from
the side. Additionally, the comet's motion, when
combined with Earth's changing perspective, has
caused the comet to have shifted relative to the
background stars. The curved path of Comet Holmes
shows it to be undergoing apparent retrograde
motion as the Earth orbits quickly in front of
it. (2007-2008)
http//antwrp.gsfc.nasa.gov/apod/ap080205.html