Transcript b 03 Other Obj in Sol System combo ppt

Other Objects in the Solar System
• Scientists find valuable information about the origin and
evolution of our universe from examining other objects in
our Solar System.
Copy down the purple sections.
Planetary Moons
• Satellites or Moons – large natural objects that revolve
around planets
• moons contain huge amounts of useful minerals that
humans may mine one day
Some Moon Facts
• Average distance from Earth: 384 000 km.
Due to the elliptical nature of the orbit - Minimum distance: 363 000 km (called perigee)
- Maximum distance: 405 000 km (called apogee).
• Diameter:
3 500 km (1/4 that of Earth's)
– However as viewed from Earth, the size of the Moon appears to
change by as much as 11% from perigee and apogee.
• Orbital path: elliptical but constantly slightly altered
In addition to the Earth's gravity, the Sun is also exerting a
gravitational force on the Moon as well. The Sun's gravity
sometimes causes the Moon to speed up or slow down slightly
in its orbit.
• Rotation:
it takes 27.3 days to turn once on its axis
(this is why we always see the same face of the moon)
• Surface:
filled with hills and valleys as well as craters caused
by the impact of large and small objects from space
Moon & Tides (4:00 min): http://www.youtube.com/watch?v=rRPtNAA-9UE
Cookie, onion, orange analogy (2:00 min): http://www.youtube.com/watch?v=CTQ6ciHENgI&NR=1
Recall: Phases of the Moon
Asteroids
Asteroids – made up of stoney/rocky and “metallic”
materials (eg. iron)
• rich in minerals (like planetary moons)
• largest asteroid is only about 100 km in diameter
• about 91 Apollo asteroids have been identified – potential
for colliding with Earth (theory for extinction of the
dinosaurs)
• called minor planets or planetoids
• rocky leftover mass of the inner
planets
Asteroid belt – between Mars and Jupiter there is
a ring of asteroids
• Scientists think it might have formed into a
planet if the gravitational force of Jupiter weren’t
so strong
Meteors and Meteorites
Meteoroid – lump of rock or metal that travel throughout the solar
system with no fixed path
• similar in origin to asteroids and comets
• when trapped by Earth’s gravity it is pulled through the Earth’s
atmosphere
• This causes the meteoroid to heat up and vapourize due to the
friction with the molecules in the atmosphere which results in a…
Meteor
-incorrectly called“shooting star”
- bright streak of light across the sky, occurs in seconds
•Most of the meteoroids are completely burned up in our atmosphere,
however, a few very large ones will get through and are then called…
Meteorites
- if a meteor does not burn up completely and strikes the
Earth’s surface
- produces craters when they hit the ground
Example: Barringer Crater, Winslow, Arizona, at 1.2 km in
diameter, smaller crater
Other craters:
This incredible 72km wide impact crater in Quebec
has slowly transformed into its current state. What
was originally the rim of the crater has since eroded
away due to glaciation. The impact occured around
212 million years ago and the diameter of the
meteorite is estimated to have been approximately
5km.
With an astounding diameter of around 300km,
Vredefort basin in south Africa is currently the largest
confirmed impact crater on Earth and also one of the
oldest at 2 billion years. the crater was the result of an
extreme impact with an object whose diameter was
10km.
How Much Damage?
What causes meteor showers?
a) Lots of falling stars
b) Clouds
c) Debris left in the path of a
comet
d) Solar wind particles
Meteoroid Shower
• Meteoroid shower often occurs when the Earth cross
the orbit of comets. The many particles left by the dust
tail of the comets ‘collide’ with the Earth, causing the
meteoroid shower.
The Cause of Meteor Showers
P55/Tempel-Tuttle
The 1833 storm
The 1966 storm
1997 Leonids from Orbit
Meteor shower
associated with the
comet Tempel-Tuttle.
The Leonids get their
name from the location
of their radiant in the
constellation Leo: the
meteors appear to
radiate from that point
in the sky.
Comets
Comets – chunk of frozen matter that travels in a very long
orbit around the sun
• basically a “dirty snowball” (ice, dust and gas) with an
elliptical orbit around the sun
• icy leftovers of the outer solar system
• as it approaches the sun, it is warmed and the frozen
substances become gas creating a gaseous head and
long tail
• Example: Halley’s Comet – returns every 76 years
The most distant
region of the
solar system is
the Oort Cloud.
- It consists of
billions of
fragments of ice
and dust, and is
thus a major
source of
comets.
Comets
• The strong gravity of the
Outer Planets sucked in
most of the comets in
between Jupiter and
Neptune, either sending
them to a collision course
with other planets, or
ejecting them to the Kuiper
Belt and the Oort Cloud.
• Comets beyond the orbit of
Neptune have time to grow
bigger and stay in stable
orbit. Pluto may be (the
biggest) one of them.
Comet Tails
• Comets
develop tails
only when the
get close
enough to the
Sun.
• Comet tails
always point
away from the
Sun—This is
how scientists
first realized
the existence of
solar wind.
Composition of Comet Tails
•
•
Plasma tail consists of
gas escaping from the
coma. The gas are
ionized by solar UV
radiation. Since they are
charged particles, solar
wind carries them
outward from the Sun.
The plasma tails always
point away from the Sun.
Dust tail consists of dustsized particles from the
coma. They are pushed
by the radiation pressure
(sun light), and generally
curve back to the
direction where they
came from.
Hyakutake
Hale-Bopp
Comet Halley 1910
Orbit Link
•Comet Halley was visible in
1910 and again in 1986. Its
next passage will be in early
2062. The period of its orbit is
every 76 years.
•The average period of
Halley's orbit is 76 years but
you cannot calculate the
dates of its reappearances by
simply subtracting multiples
of 76 years from 1986. The
gravitational pull of the major
planets alters the orbital
period from revolution to
revolution.
Two Showers for Halley due to
The Orionid meteor shower is one of two showers that occur annually when
Earth passes through Halley's Comet dust and debris.
http://www.suite101.com/content/the-orionid-meteor-shower-is-debris-from-halleys-comet-a280661#ixzz1AukiHym8
Home FUN!:
1. Finish Glossary handout.
2. Start to Review for Quest on Monday, January 17, 2011.