Transcript the sun

 Read
“ A Return to the Moon” page 659
 Answer
questions 1 and 2 in your journal

This chapter is going to cover
 The major bodies in the solar system
 The differences between the inner
and outer planets
 The Copernican Revolution
 Models of the solar system
 The formation of the moon
 In
this section we will learn about:
 The structure of the solar system
 The role of gravity in planetary
orbits
 Moon phases
 Lunar and solar eclipses
 Tides
Why does the night sky look the way it does from
Earth?
 What objects make up the solar system?
 How does the moon affect Earth?
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Vocab
 Planet
 Solar system
 Satellite
 Phase
 eclipse
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The sun, moon, and starts appear to rise and
set each day because Earth spins on its axis.
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The stars that are visible at night change
throughout the year as Earth orbits the sun.
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Both of these movements
 Affect our view of the sky
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The night sky will look different tonight than
it will in 6 months.
Star groups can move through the sky in just a
few hours!
The positions of object in the sky change over
time because Earth, and everything else in the
universe, is constantly moving.
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Earth’s spinning on its axis and orbiting the
sun create movement in the sky.
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Distant objects in the sky tend to move slowly
and together.
 Ex: stars
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Closer objects move across this background of
stars.
 Ex: planets and comets
 Planet-
 a celestial body that orbits the sun
 is round because of its own gravity
 has cleared the area around its
orbital path
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Celestial- of or relating to the sky or visible
heavens.
 It’s an adjective
 Ex: sun, moon, and stars
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It took thousands of years for people to
realize that the sun is a star.
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Because the sun is so close to us, the sun
is the brightest object in the sky.
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Our atmosphere scatters the sun’s light.
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This blocks our view of the stars.
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The sun is an average star.
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It is not particularly hot or cold.
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The sun is of average size.
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Diameter: 1.4 million kilometers.
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The sun’s diameter is about 110 times Earth’s.
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The sun has a mass that is about 330,000 times
the mass of Earth.
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The sun is the major external source of
 Heat
 Light
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As the Earth turns on its axis every 24 hours,
we see the sun rise and set.
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Many patterns of human life, such as rising in
the morning, eating meals at certain times, and
sleeping at night, follow the sun’s cycle.
TULIPS ARE VERY SENSATIVE TO
SUNLIGHT. THEY OPEN DURING
THE DAY AND CLOSE AT NIGHT.
ENERGY FROM THE SUN IS ALSO THE
MAIN CAUSE OF WEATHER
PATTERNS AND OCEAN CURRENTS.
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Constellations- are groups of stars organized
in recognizable patterns.
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Ancient Greek scholars first saw
constellations and named them.
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They also saw the planets wander in regular
paths among the stars.
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The ancient Greeks calculated that the stars
were more distant than the planets were.
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After the invention of the telescope, people
found other objects in the night sky..
 Many faint stars
 Two more planets, Uranus and Neptune
 Several other large celestial bodies, Ceres and
Pluto
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Solar System- is the sun and all of the objects
that orbit it.
The sun is the most important
The sun makes up about 99% of the total mass
of the solar system.
The eight planets and their moons make up
most of the remaining 1%.
It also contain other small objects
 Dwarf planets, asteroids, comets, dust and gas.
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Every object in the solar system pulls on every
other object.
The greater an objects mass, the larger the
gravitational force an object exerts on one
another.
The closer two objects are to each other, the
stronger the gravitational pull is between
them.
The sun exerts a large force because its mass
is so large.
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The pull of the sun keeps the Earth in its orbit.
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With out the sun’s pull, Earth and all of the
other planets would shoot off into space.
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Even at great distances, the sun keeps the
planets in their orbit.
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Gravity is also the force that keeps moons
orbiting around planets.
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Planets can be seen because their surface or
atmosphere reflect sunlight.
A planet’s distance from the sun determines how
long it will take the planet to orbit the sun.
 Mercury is the closest and it takes 88 days.
 Earth takes 1 year
 Neptune, the most distant, takes 165 years
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Satellite- an object in orbit around a body that has
a larger mass.
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The moon is the Earth’s satellite because the
Earth has a larger mass.
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The four planets closest to the sun are small and
rocky and have few or no satellites.
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The next four are large and gaseous and have
many.
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All of the planets in our solar system except
Mercury and Venus have moons.
We know of 135 natural satellites or moons
orbiting planets.
The smallest satellites are less them 3km in
diameter.
All moon are held in their orbits by the
gravitational forces of their planets.
Satellites also reflect sunlight so we can see
them from Earth.
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The moon’s surface is covered with craters,
caused by asteroid collisions.
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The maria, or large, dark patches on the moon
are areas of lava that flowed out of the moon’s
interior, filled the impact craters and cooled as
solid rock.
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Like the sun, the moon affects life on Earth
through its movements and gravitational
influence.
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The moon has different phases throughout each
month.
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The position of Earth, the sun, and the moon
determines the phases of the moon.
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The time from one full moon to the next is 29.5
days.
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Many calendars have been based on the movement
of the moon.
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When Earth, the sun, and the moon are in a
straight line, observers on Earth may witness
an event known as an eclipse.
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An eclipse occurs when one object moves
into the shadow cast by another object.
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During a new moon, the moon may cast a
shadow onto Earth. Observers within that
small shadow on Earth see the sky turn dark as
the moon blocks out the sun. This event is a
solar eclipse.
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Look at Figure 9 on page 658
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When the moon is full, it may pass into the
shadow of the earth. All the observers on the
nightside of Earth can see the full moon
darken as the moon passes through Earth’s
shadow. This event is called a lunar eclipse.
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Look at Figure 9 on page 658
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Coastal areas on Earth, have two high tides
and two low tides each day. This happens
because the Earth rotates.
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Because the moon is also orbiting the Earth,
the times of these tides change throughout the
month.
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Tides are mainly a result of the gravitational
influence of the moon. The sun has a minor
effect.
 Define
the 5 vocab words for Section 1
Page 653
 Section 1 Review page 660
 Do #1-8
 You
do not have to write the question
 Make sure you answer all parts of the
question/questions.
 Read
“Exploring Planets” page 665
 Answer
question 1 in your journal

This section introduces the characteristics of
the inner and outer planets.
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The important characteristics of each planet.
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A discussion of objects beyond the orbit of
Neptune, including the Kuiper Belt.
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How are the inner planets similar to one another?
What are gas giants?
What type of bodies lie beyond the gas giants?
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Vocab
 Terrestrial planet
 Hydrosphere
 Asteroid
 Dwarf planet
 Gas giant
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Terrestrial Planets- are highly dense and near the
sun, Mercury, Venus, Earth, and Mars.
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The terrestrial planets are small and have solid
rocky surfaces.
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Scientists study these planets with telescopes,
satellites, and surface probes.
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Inner planets have metallic cores and rocky
surfaces like mountains, canyons, and craters.
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We did not know much about Mercury until we
sent the space probe Mariner 10.
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Mercury is covered with craters.
It is never very far from the sun. (small orbit)
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Mercury is 0.4 AU from the sun.
 astronomical unit.
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Surface temperature 720 K
Mercury has almost no atmosphere or water.
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Venus is 0.7 AU from the sun.
It can be seen near sun rise or sun set and is
called the morning or evening star.
Surface has mountains and plains.
Spins slowly in an opposite direction.
Venus is hot and its atmosphere contains large
amounts of sulfuric acid.
The CO2 in the atmosphere absorbs the
radiation causing an increase in atmospheric
temperature. Greater than 700K.
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Third planet “rock” from the sun.
We measure other planets in the solar system in
relation to Earth.
Earth rotates on its axis in 1 Earth day.
Only planet that sustains life.
Only planet with lots of liquid water.
Hydrosphere- all of the liquid and frozen water
on Earth.
Hydrosphere helps moderate the temperature of
Earth.
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Earth’s surface does not freeze at night
because of the greenhouse effect- atmosphere
absorbs energy radiated by the sun.
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Earth’s atmosphere is composed of
 78% Nitrogen
 21% Oxygen
 1% Carbon dioxide and other gases
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Debris travel through the atmosphere and heat up
and vaporize or shatter before they reach Earth.
Only large objects can survive the trip.
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Earth’s original atmosphere changed over time.
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 Used to be more carbon dioxide, methane and ammonia
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The atmosphere protects us from
 Harmful ultraviolet radiation
 High energy particles from the sun
 Space debris
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No humans have visited Mars, only probes.
 Viking 1 and Viking 2 in 1976
 In 2004, two Mars Exploration Rovers
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Mars has polar ice caps made of frozen carbon
dioxide and frozen water.
We think water used to flow across the surface as a
liquid.
Very thin atmosphere composed of CO2
Has 2 small satellites, Phobos and Deimos
Mars is very cold, surface temperature 144-300K
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Martian volcano Olympus Mons- largest mountain
in the solar system.
 Mars has low gravity, lava flows lower, larger
volcanoes
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Many impact craters
 Thin atmosphere lets them in, and no water causes
them to weather slowly.
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Mars is red because of iron oxide in its soil.
Frequent dust storms that form large red dunes.
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Asteroids- a small rocky object that orbits the sun,
 most asteroids are located in a band between the orbits of
Mars and Jupiter.
 The odds of an asteroid hitting Earth is small.
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The largest celestial body in the asteroid belt is
Ceres.
 Scientists used to think it was a planet.
 It is a dwarf planet- a celestial body that orbits the sun, is
round because of its own gravity, but has not cleared its
orbital path.
Asteroid Belt
out side of
Mars’s orbit
Martian volcano
Olympus Mons- largest
mountain in the solar
system
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Jupiter, Saturn, Uranus, and Neptune
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The outer planets are
 much larger than the inner planets
 have thick, gaseous atmospheres
 many satellites and rings.
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A spacecraft cannot land on a gas giant because it
has no solid surface.
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The Cassini-Huygens probe reached Saturn in 2004
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The rings of Saturn were discovered in 1659
 Thin rings of other gas giants were found much later with
modern technology.
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Uranus’s rings were discovered in 1977
Most of the satellites were discovered during space
missions.
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Jupiter 60+
Saturn 40+
Uranus 27
Neptune 13
▪ Most are cratered and have thin atmospheres
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First planet beyond the asteroid belt.
Largest planet to orbit the sun. 1,300 times the size
of Earth.
It takes 12 Earth years to orbit the sun. (5 AU)
Atmosphere has clouds of hydrogen, helium,
methane and ammonia. (jet streams, storms)
The Great Red Spot- a huge hurricane that measures
more than twice the diameter of Earth. It has existed
for hundreds of years.
4 Satellites- Ganymede, Callisto, Io and Europa.
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It takes more than 29 years to orbit the sun.
A day on Saturn in 10.7 hours long
It rotates faster at the equator and slower at the
poles.
The rings are made of dust, rock and ice.
The gravitational force from Saturn and its satellites
hold the particles in place.
We do not know how the rings formed.
 Left over material when the planet formed
 Pieces of a smashed satellite
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Methane gives both planets their blue color
Thick gaseous atmospheres
Smaller than Jupiter and Saturn
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Uranus- William Hershel 1781
 19AU, cold
 84 years to orbit the sun
 Most extreme seasons because its tilted 98 degrees
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Neptune- Johann Galle 1846
 30 AU, storms like Jupiter, cold
 165 years to orbit the sun
 Beyond
the gas giants are
 Numerous small bodies
▪Composed of
▪Rock
▪Ice
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Pluto was recorded as a planet until 2006
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International Astronomical Union
 Met in 2006
 Voted on a definition of the word planet
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Pluto does not clear the area around its orbital
path of debris, it’s a dwarf planet.
A thick gaseous atmosphere and a solid icy
surface.
Distance from the sun is 40AU
248 Earth days to complete one orbit
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Kuiper Belt- populated by many small bodies
of ice and rock, like Pluto.
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Astronomers are actively exploring this area.
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Scientists have found many large bodies in
this region.
 Eris- larger than Pluto
 Dwarf planet
 Distance from sun 90AU
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Section 2 Review page 670

Answer questions # 1-8

Due tomorrow!

You do not have to write the question

Make sure you answer all parts of the
question/questions.


5 Vocab on page 661
Section 2 Review page 670

Answer questions # 1-8

Due tomorrow!

You do not have to write the question

Make sure you answer all parts of the
question/questions.
Meteor Crater is one of the youngest and bestpreserved impact craters on Earth. The crater formed
roughly 50,000 years ago when a 30-meter-wide, ironrich meteor weighing 100,000 tons struck the Arizona
desert at an estimated 20 kilometers per second.
The resulting explosion exceeded the combined force
of today's nuclear arsenals and created a 1.1kilometer-wide, 200-meter-deep crater.
 Read
“Where are Earth’s Craters”?
Page 677
 Answer
journal.
questions 1 and 2 in your
 Ancient
 Modern
models of the solar system
nebular model for the solar
system’s formation.
 Small objects in the solar system like
comets, asteroids, and meteors.
 How the Earth’s moon was formed.
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How did early astronomers understand and study
the solar system?
Why is the solar system organized like it is?
What else is the solar system besides planets?
How did Earth’s moon form?
How do astronomers find planets around other
stars?
Vocab- nebular hypothesis, nebula, comet,
exoplanet
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Many groups of people watched the sky.
Stonehenge was used to keep time.
 Its stones are aligned with the seasonal solstices.
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Ancient people used myths to explain what they did
not understand.
Mathematical tools began to be used to make more
accurate models of observed astronomical objects.
Ancient questions helped develop
 Science
 Scientific method
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Aristotle –Greek philosopher, explained the phases
of the moon and eclipses by using a model of the
solar system with Earth at the center.
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Geocentric or “Earth centered”
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Copernicus- In 1543, proposed a
heliocentric model.
Earth and the other planets orbit
the sun in a perfect circles.
Look at Figure 2 pg.672
Kepler- improved the model by
figuring out that the orbits are
ellipses or ovals and not circles.
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No one knew why planets orbited the sun in
elliptical orbits until 1687.
Newton- explained that gravity keeps the planets in
orbit around the sun and satellites in orbit around
the planets.
Every object in the universe experts a gravitational
force on every other object.
Proposed that everything in the universe follows the
same rules and acts in a predictable way.
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Scientists estimate that the solar system is 4.6
billion years old.
Nebular hypothesis- a model for the formation of
the solar system in which the sun and planets
condense from a cloud or nebula of gas and dust.
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This hypothesis explains
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 why objects that form from a disk will lie in the same
plane
 have almost circular orbits
 Orbit in the same direction
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Accretion- the process by which small particles
collide and stick together.
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Warm temperatures near the sun prevented light
gases from remaining in the atmosphere of the
terrestrial planets.
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Colder gas and dust in the outer part of the disk
became the gas giants.
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Satellites may have formed around gas giants because
of accretion.
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Particles could have been captured by the gravitational
pull of gas giants.
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Small satellites could have broken off from larger ones.
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Most satellites orbit planets in the same direction that
the planets orbit the sun.
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Look at Figure3 pg674. Know this figure.
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Comet- a small body of ice, rock, and cosmic dust
that follows an elliptical orbit that gives off gas and
dust in the form of a tail as it passes close to the
sun.
Satellites orbit planets, comets are prob. composed
of material left over from the formation of the solar
system.
Most asteroids can be found between Mars and
Jupiter.
Meteorite- a meteoroid that does not completely
burn up when entering the atmosphere.
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Comets are composed of dust and ice made from :
 methane, ammonia, carbon dioxide, and water.
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1994- pieces of the comet Shoemaker-Levy 9
collided with Jupiter.
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This showed that the comet also contained:
 silicon, magnesium, and iron.
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When a comet passes the sun, it gives off gases in
the form of a long tail.
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Some comets have two tails.
 An ion tail made of charged particles that is blown by the
solar wind.
 A dust tail that follows the comet’s orbit.
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A comet’s orbit is very long.
A comet’s tail will brighten when it passes the sun.
 The far-flung pieces
leftover from the
formation of our solar
system make up the
Oort cloud of comets,
which may be up to
100,000 AU wide and
extend in all directions.
• Planetesimals that
remained in the nebular
disk formed the Kuiper
belt beyond the orbit of
Neptune.
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There are three major types of meteorites.
 Stony meteorites include carbon-rich specimens
that contain organic materials and water.
 Metallic meteorites are made of iron and nickel.
 Stony-iron meteorites are a combination of the two
types.
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Objects less than 10 m across usually burn up in
Earth’s atmosphere.
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Meteoroids that strike Earth may leave craters.
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Over time, natural and manmade forces may erode
craters on Earth.
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Some past climate events and extinctions are thought
by scientists to have been caused by large meteor or
comet strikes.
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The current theory is that the moon resulted
from a collision between Earth and another
large body.
1. Earth collided with a large body.
 The body that struck Earth may have been as large
as Mars.
 At impact, a large part of Earth’s mantle was
blasted into space.
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2, The ejected material clumped together.
 The debris consisted of the iron core of the body,
mantle material from Earth, and other material
from the impacting body.
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3. The moon began to orbit Earth.
 The moon is the only large satellite around a
terrestrial planet and it is the largest moon with
respect to its planet.
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Astronomers have discovered more than 200
exoplanets by measuring the small
gravitational effects that they have on their
parent star.
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exoplanet: a planet-like body that orbits a star
other than the sun
As an exoplanet orbits its star, it causes the star to
wobble back and forth.
Most of the newly discovered exoplanets have
masses close to or larger than the masses of Jupiter
or Saturn.
Only a few exoplanets are in systems that have
more than one discovered exoplanet.
Modern detection methods favor the finding of
large exoplanets, thought scientists are working on
ways to detect smaller exoplanets.
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Chandrayaan-1 was launched successfully,
without a hitch, on October 22, 2008.
Chandrayaan-1 will make one complete
revolution around the earth in 11 days. The
Chandrayaan-1 will come into the vicinity of
the moon during its second revolution around
the world.
The Chandrayaan-1 will map not only the
surface of the moon but also what lies
beneath it. ISRO will use a 3,080-pound
lunar probe for creating a high-resolution
map of the lunar surface and the minerals
found below it.
An important objective of Chandrayaan-1 is
to find Helium-3 gas, a rare isotope, which
could be used as a replacement for fossil
fuels and also to power nuclear fusion.

Section 3 Review Page 679

Answer questions #1-9

Due tomorrow

You do not have to write the question

Make sure you answer all parts of the
question/questions.
 4 Vocab words page 671
 Section 3 Review Page 679
 Answer
questions #1-9
 Due
tomorrow
 You
do not have to write the question
 Make
sure you answer all parts of the
question/questions.
 List
the planets in order and
list a distinguishing
characteristic for each planet.
Chapter
19 Review on
page 684
Do
# 1-23, 29-32
You
have 5 minutes to
look over your vocab.