Download Unit 8 Chapter 28 Notes

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Unit 8 Chapter 28 Minor Bodies of the Solar System
Section 1 Earth’s Moon
In 1957 the Soviets launched “Sputnik” which was the first satellite into space.
In 1958 the US launched our first satellite into space.
In 1959 the Soviets launched a probe called “Luna” which was the first manmade object to encounter the moon.
Exploring the Moon
In 1969 the Apollo Astronauts walked on the moon.
In 1972 the final Apollo mission brought back to Earth about 400kg of moon
rocks.
Interesting facts:
The moon is _____________________________________
Moon’s diameter is ________________________________
Moon’s mass _____________________________________
Moon’s density ___________________________________
Gravity is 1/6 of the Earth’s
Ex.
150 lb. Man weighs = 25 lbs.
200 lb. Equipment = 33 lbs.
350 lbs.
= 58 lbs.
The temperature range is from 134o in the day to -17 o at night
Lunar Surface
_____– name for baby moon
Lunar – _______________________________
Lava flowed on the surface due to the strength of these impacts. The cooled
lava formed flat dark surfaces (called lunar Maria).
When we first started to study the moon, we thought the dark areas were filled
with water. That is why the scientists named them “Maria”. It is
the Latin word for seas. The dark areas are actually filled with
hardened lava.
Mascons ____________________________. Scientists believe it is that way
because of the type of lava that was released.
Craters, Rilles and Ridges
The moon looks like a giant golf ball with all of the impact crates on it.
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Craters were formed when meteors hit the surface. They varied in size which
caused some shattered rock and dust to splash out of the craters
like “rays”.
The impacts were thought to be caused by meteoroids, comets or other debris
colliding with the surface creating craters or depressions.
Rille: ___________________________________________________________
____________________________________________________
Highland: _______________________________________________________
Regolith
Regolith is _______________________________________________________
Lunar Rocks
The rocks on the moon are similar to those on Earth except they have different
proportions of the elements involved. They also have less of
certain common elements which are thought to be boiled off
because of the lack of atmosphere.
The Interior of the Moon
The density of the moon is about 3/5th of Earth’s.
The moon has moonquakes (like earthquakes) which allowed scientists to create
a model of the interior of the moon. It has layers of solid rock with
different densities, no pure liquid layer.
The Moon’s Crust
One side of the moon always faces the Earth.
Nearside – ________________________________________
Farside – __________________________________________
The Moon’s mantle and core
The moon’s mantle is made of silica, magnesium and iron. It is approximately
half the distance of the radius.
Iron core is approximately 700km thick
It has almost no magnetic field.
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The Formation of the Moon
Rocks taken from the moon by the Apollo Astronauts provided us with incite into
the history of the moon’s formation.
The Giant Impact Theory
The giant impact theory states that more than 4 billion years ago a giant
Asteroid (the size of Mars) hit the molten Earth. The collision
ejected a chunk that later clumped together and hardened into the
moon.
Differentiation of the Lunar Interior
The denser surface material moved toward the center of the moon because of
the rotation of the moon. The other materials that were dense but
not as dense settled in the layer in between the core and crust.
The lighter materials stayed on top.
Meteorite Bombardment
In the beginning the moon was bombarded frequently. After time the impacting
slowed down. The craters we see were the original features, so
Scientists use that information to learn about the early solar
system.
Lava Flows on the Moon
After the impacts stopped, lava started to flow out of the cracks and fissures.
Where the lava came from Scientists are still trying to figure it out.
However, they feel that the flows ended about 3.1 billion years
ago.
Section 2 Movement of the Moon
The moon revolves around the Earth from west to east, once every 271/3 days
but it appears to travel from east to west in the sky. Why?
The earth rotates West to East.
The Moon’s Elliptical Orbit
The moon’s orbit is not in the same plane as the Earth. The angle is about ____
which is why we have eclipses.
Perigee – _____________________________________________
Apogee – _____________________________________________
The moon and the sun appear to be about the same size – why
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Moon Rise and Moon Set
If the moon’s orbit is 271/3 days, how come it takes 291/2 days from one full
moon to the next?
__________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
__________________________________________________________________________________________________
Lunar Rotation
The moon rotates (turns on axis) in the exact same time it revolves (moves
around earth). This means that the same side of the moon is
always facing us.
Eclipses
Eclipses occur when on celestial body passes through the shadow of another.
The Moon and the Earth cast a shadow that has 2 different parts
Umbra _____________________________________
Penumbra – ______________________________________
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Solar Eclipses
Total Solar Eclipses
-
occurs when moons umbra shadow reaches to earth.
the moon blocks out sunlight
can only happen when the moon is closest (perigee)
in orbit to the earth
Only in the new moon phase
Partial Solar Eclipses
The moons penumbra shadow reaches the earth. Happens around the
umbra shadow or when the moon is farthest (apogee) in orbit around the
earth
At least one solar eclipse occurs every 18 months. A given area experiences a
total solar eclipse only once every three to four centuries. They only last for
about 7 ½ minutes anyway. The next one for us in North America will occur in
2017.
Effects of Solar Eclipses
Diamond ring Effect:
During a total solar eclipse, people on the ground are in the moon's umbra. In
the areas on Earth's surface under the umbra, the sky becomes as
dark as it does at twilight. During this period of darkness, the
sunlight that is not eclipsed by the moon shows the normally
invisible outer layers of the sun's atmosphere.
Annular Eclipse
During an annular eclipse, the sun is never completely blocked out. Instead, a
thin ring of sunlight is visible around the outer edge of the moon. The brightness
of this thin ring of ordinary sunlight prevents observers from seeing the outer
layers of the sun’s atmosphere that are visible during a total solar eclipse. An
annular eclipse will be visible from the American Southwest on May 20, 2012.
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Lunar Eclipses
Lunar Eclipses
Happens only when there are full moons
The earth’s shadow blocks out the sunlight and
and the moon doesn’t’ reflect back the sunlight.
Total eclipses – moon passes into umbra
Partial eclipses –
moon passes into penumbra; occurs only at new moon
A lunar eclipse lasts for several hours. Even during a total lunar eclipse, sunlight
is bent around Earth through our atmosphere. Mainly red light
reaches the moon, so the totally eclipsed moon appears to have a
reddish color
Frequency of Solar and Lunar Eclipses
As many as seven eclipses may occur during a calendar year. Four may be lunar,
and three may be solar or vice versa. However, total eclipses of the sun and the
moon occur infrequently. Solar and lunar eclipses do not occur during every
lunar orbit. This is because the orbit of the moon is not in the same plane as the
orbit of Earth around the sun. The moon crosses the plane of Earth’s orbit only
twice in each revolution around Earth. A solar eclipse will occur only if this
crossing occurs when the moon is between Earth and the sun. If this crossing
occurs when Earth is between the moon and the sun, a lunar eclipse will occur.
Lunar eclipses are visible everywhere from the dark side of Earth. A total solar
eclipse, however, can be seen only by observers in the small path of the moon’s
shadow as it moves across Earth’s lighted surface. A partial solar eclipse can be
seen for thousands of kilometers on either side of the path of the umbra.
Phases of the Moon
Phases of the Moon:
-
are daily changes in the moons appearance
It is when sunlight is reflected off the moon’s surface
the moon revolves around the earth
1/2 of the moon is always lit by the sun (except for
lunar eclipses)
We see different portions of the lit half of the moon
Earth Shine is when sunlight is reflected off of the moon.
Waxing Phases of the Moon
Waxing phase - the lit half is becoming bigger this happens during the first two
weeks
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Crescent – a slight sliver is illuminated on the right side
Quarter – when half of what is visible is illuminated on the right side
Gibbous - more than half of the right side of the moon is bright and the other
part is dark
Waning Phases of the Moon
Waning phase - the lit half is becoming smaller, this happens during the second
two weeks
Crescent – a slight sliver is illuminated on the left side
Quarter – when the left half of the moon is visible is illuminated
Gibbous – the left side of the moon is bright and the other part is dark
Time from New Moon to New Moon Phases
Phases listed:
Day 1 – ___________________________
Day 3 ____________________________
Day 7 ½__________________________
Day 11 ½ _________________________
Day 14 ½ _________________________
Day 18 ½ -________________________
Day 22 ½ -________________________
Day 26 -___________________________
Day 29 ½ -_________________________
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Section 3 Satellites of the Other Planets
Until the 1600’s everyone thought that we were the only ones with a moon. In
1610 Galileo discovered 4 moons orbiting Jupiter and he also saw the rings of
Saturn.
Moons of Mars
Mars has two moons Phobos and Deimos
Moons of Jupiter
Jupiter has 67 moons.
The largest 4 are called Galilean Moons because he discovered them
Io, Europa, Ganymede, Callisto
Moons of Saturn
Saturn has 63 Moons
The largest one is called Titan
Moons of Uranus and Neptune
Uranus has 27 Moons
Neptune has 13 Moons
Pluto’s Moons
Pluto has 3 moons.
Charon is half the size of Pluto
Hydra and Nix were discovered in 2005
Rings of Gas Giants
Saturn's spectacular set of rings, shown was discovered more than 300 years
ago. Each of the rings circling Saturn is divided into hundreds of small ringlets.
The ringlets are composed of billions of pieces of rock and ice. These pieces
range in size from particles the size of dust to chunks the size of a house. Each
piece follows its own orbit around Saturn. The ring system of Saturn is very thin.
The other gas giants have rings as well. These rings are relatively narrow.
Jupiter’s were not discovered until the Voyager 1 spacecraft flew by Jupiter in
1979. Jupiter has a single, thin ring made of microscopic particles that may have
been given off by Io or one of Jupiter's other moons. The particles may also be
debris from collisions of comets or meteorites with Jupiter's moons. Uranus also
has a dozen thin rings. Neptune's relatively small numbers of rings are clumpy
rather than thin and uniform.
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Section 4 Asteroids, Comets and Meteoroids
There is a lot of space junk out there!
Asteroids
An asteroid is a small planet like bodies made entirely of rock with irregular
shapes. Most orbit in a belt between Mars and Jupiter, called the asteroid belt.
They revolve in the same direction as the planets. The 2 largest Ceres (about
1000 km is also considered a dwarf planet) & Pallas are spherical (diameters
about 11,000km).
In 1908 a small asteroid exploded with the force of a 10-megaton detonation
over Tunguska, Siberia.
Composition of Asteroids
There are 3 categories of asteroids
____________________________
______________________________
_________________________________________
Near-Earth Asteroids
More than a thousand asteroids have orbits that sometimes bring them very
close to Earth. These asteroids have wide, elliptical orbits that bring them near
Earth's orbit.
Barringer Meteorite Crater, also known simply as Meteor Crater, in Arizona, has a
diameter of more than 1 km which scientists believe came from an asteroid that
had a diameter of less than 50 m. Dozens of such craters have resulted from
past impacts on Earth, but most craters have eroded or have been covered by
sediment.
We now have set up a few detection agencies to help detect them before its too
late.
Comets
Comets are small bodies of ice, rock, and cosmic dust that follow highly elliptical orbits
around the sun. The most famous is Halley's Comet, which passes by Earth every 76
10
years. It last passed Earth in 1986 and will return in 2061. Every 5 to 10 years, another
very bright comet will be visible from Earth. Comet Hale-Bopp was particularly
spectacular as it passed Earth in 1997, as was comet McNaught in 2007.
Composition of Comets
The composition of a comet is mainly water, carbon dioxide, methane and
ammonia.
When close to the sun the comet reflects light and solar winds push off particles
of the comet to form a tail. The tail always points away from the sun. The head
is made of mainly ice and rock material.
The Kuiper Belt
The Kuiper Belt is found beyond Neptune. It is where Pluto lives and where we
are currently finding more and more dwarf planets, comets and other space
“junk”.
The Oort Cloud
The Oort cloud is a spherical cloud of dust and ice that lies far beyond Neptune’s
orbit and that contains the nuclei of billions of comets. The total mass of the
Oort cloud is estimated to be between 10 and 40 Earth masses. It surrounds the
solar system and may reach as far as halfway to the nearest star. Scientists think
that the matter in the Oort cloud was left over from the formation of the solar
system
Short-Period Comets
A short period comet takes less than 200 years to complete one orbit. Halley’s
Comet is one of them, it takes 76 years.
Meteoroids
Most meteoroids are less than 1mm in diameter. They are usually chunks of
rock which are moving through space.
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Meteors
Meteors
-
Rock that passes through our atmosphere. We see a light as it
passes through the atmosphere. As the particles move through the
atmosphere, friction creates enough heat to make the rock glow
and melt.
A Fireball will occur when a meteor burns up and becomes a brilliant flash of
light in the sky.
Meteor shower
A shower will occur when earth passes through a tail of a comet.
The shower is named for the Constellation from which they appear
to migrate from. They will occur at the same time each year.
Meteorites
Meteorite -
rock that remains after a meteoroid hits the earth.
Three types:
1.
Stony – common 94% of them
2.
Iron – 5% of them
3.
Stony Iron – 1% of them