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Chapter 19
Chapter 19 Section 1
Sun, Earth, and Moon
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The sun, moon, and stars appear to rise and set each day because earth
spins on its axis.
The View from Earth:
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Over time brighter objects change the directions and cross the path of
stars.
The Greeks called these objects planets which means “wanderers”.
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The Sun is Our Closest Star
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It took thousands of years for scientist to realise the earth is a star.
Because the sun is so close to us it makes is very bright. Our atmosphere
scatters the sun and makes the daytime so bright we can't see the other
stars.
The Sun is an Average Star:
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Diameter- 1.4 million kilometers about 110 times the earth.
Its mass is over 300,000 times the size of earth.
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Everything Revolves Around the Sun
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The sun is not just the object all the planets orbit, it is also the source of
heat and light for the entire system.
Many patterns of human life follow the sun's cycle.
Such As:
-Rising in the morning
-Eating meals throughout the day
-Sleeping at night
Heat from the sun are the main cause of weather patterns on earth.
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Planets and Distant Stars are Visible in the
Night Sky
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By watching the stars for many years the ancient Greeks calculated that
the stars were more distant than the planets
Over a thousand years later after the invention of the telescope people
found other objects in the night sky. This included many faint stars and
three more planets. (Uranus, Neptune, and Pluto)
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Videos
https://www.youtube.com/watch?v=tkzdR93bqw
https://www.youtube.com/watch?v=TBmZjOHr
VJ0
http://video.nationalgeographic.com/video/101-videos/sun-101-sci
https://www.youtube.com/watch?v=7t3aXb3Lp
Wg
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Chapter 19 Section 1 Questions
The first question is going to be a question to test what you already know.
1.
What are the five planets in addition to Earth?
1.
What did the Greeks call the brighter objects that change directions and cross the path of stars?
3.
Would the sun be considered a star?
4.
What is the sun’s diameter?
5.
True or False: All the planets orbit around the Earth?
6.
Heat from the sun is the main cause of?
a. Endangering animals
b. Weather patterns on Earth
c. Lakes and rivers drying up
7.
Are stars more distant than planets?
8.
What are the other three planets that scientist found when they invented the telescope?
Made By: Siani
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Earth is a part of this solar system
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The solar system has its own parts and sets of rules
Solar System- the sun and all things that orbit around it
The sun makes up 99% of the total mass of the solar system
The 9 planets and moon make up the other 1%
The solar system has many smaller objects such as
meteoroids,asteroids,comets,gas and dust
● These objects do not have much mass, but helps us understand
the solar system better
GRAVITY HOLDS THE SOLAR SYSTEM TOGETHER
● The force of gravity between two objects depends upon their masses
and the distance between them
● The greater the mass, the larger the gravitational force exerted
● The closer the objects are, the stronger the gravitational pull
● Gravity is the force that keeps moons orbiting around planets
● You experience gravity as the force that keeps you on Earth
● The sun exerts the largest force in the Solar System, cause’ of its
mass
Eight planets orbit the sun
● Planets can be seen because their surfaces or atmospheres reflect
sunlight.
● A planet’s distance from the sun determines how long the planet take to
orbit the sun.
● Pluto, the most distant planet, takes 248 years or 90,000 days to orbit the
sun. Pluto is actually closer to the sun than Neptune is, but it’s average
distance from the sun is farther.
● Satellite- a natural or artificial body that revolves around a planet
● The moon is Earth’s satellite because Earth has the larger mass.
● The four planets closest to the sun have little to no satellites because they
are small and rocky.
Satellites orbit planets
● We know of 135 natural satellites that orbit the planets
in our solar system
● In 1970, there were only 33 known satellites
● Smallest satellites are less than 3 km in diameter
● Largest satellites are larger than Mercury (4,878 km in
diameter)
● All satellites are held in orbits by the gravitational forces
of their planets
● Most satellites reflect sunlight and have atmospheres
1. What makes up 99% of the solar system’s total mass?
2. The force of gravity between two objects depends upon
and
3. What is a satellite?
4. What do most satellites reflect?
Moon Phases
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The moon appears in 8 phases throughout the month.
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New Moon - not visible
Waxing Crescent
First Quarter - commonly called a "half moon"
Waxing Gibbous
Full Moon - the entire moon is illuminated
Waning Gibbous
Third Quarter - another "half moon", but opposite side of first quarter
Waning Crescent
Relative positions of the Earth, Moon and Sun determine the phase.
Phases of the Moon are not caused by Earth’s shadow
More on the Moon
● The moon does not directly orbit the sun, but yet it actually orbits the earth at a
distance of 384000.
● The moon’s craters are caused by asteroid collisions from early history.
The maria, or large, dark patches on the moon are where lava has flowed from out the
inside of the moon and has cooled.
Eclipses
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Eclipse- An event in which the shadow of one celestial body falls on
another.
Eclipses occur when the Earth, the Moon, and the Sun
line up.
- During a new moon, the moon casts a shadow onto
Earth. People who are within the small shadow on
Earth see that the sky turns dark and the moon blocks
out the sun, which is a Solar Eclipse.
- Solar Eclipses are rare
The Moon - Fast Facts
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● The moon does not directly orbit the sun,
but instead, orbits the Earth
● The moon is covered in craters, most likely
due to asteroid collisions
How The Moon Affects Earth’s Tides
● Every day there are two high tides and two low tides
● The tides are mainly the moon’s gravitational influence
● Because the the moon is orbiting the earth the times of these tides
change in the month
● The sun has a small effect too, when the sun is on the same side of
the earth as the moon is the tides will be the strongest
● The moon’s effect will be weaker on the side of the earth that is not
close to the moon
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Videos for moon
tides:
https://www.youtube.com/watch?v=gftT3wHJGtg
orbit: https://www.youtube.com/watch?v=6jUpX7J7ySo
pages 637-638
Questions
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Describe the features of the inner planets.
What inner planets can sustain life?
Name the terrestrial planets.
True or False the inner planets are terrestrial
planets.
Inner Planets (terrestrial planets)
● The solar system is made up of both inner and outer planets. The
inner being closer to the Sun and the outer further away.
● The inner planets are referred to as the terrestrial planets because
their composition is rocky like the Earth.
● They receive more of the Sun’s energy and have higher
temperatures than the outer planets.
● In order the terrestrial planets are Mercury, Venus, Earth, and
Mars. These planets are small, solid, and rocky.
● The surfaces of the Terrestrial planets are studied by scientists with
telescopes satellites and probes.
Mercury
● Nothing much was known about the planet until space
missions such as the Mariner 10 were sent to explore it.
● The surface of Mercury has craters distributed all along
its surface a lot like the moon.
● Due to its small orbit Mercury is never too from the sun
● To see Mercury at its best from Earth you would have to
see it just before sunrise or right after sunset.
Venus
● The thick clouds on Venus cause a runaway greenhouse effect.
These thick gases are made up of mostly carbon dioxide which
makes Venus very reflective. Venus has a thick atmosphere
which prevents releasing radiation creating the "runaway"
greenhouse effect. This keeps its temperature at 700 K.
● Radar maps measure the surface of Venus. It indicates that the
surface of Venus has plains and mountains. Although it has
different landforms, it cannot support life. Venus is hot, the
atmospheric pressure is 90 times the pressure on earth and it
contains sulfuric acid.
Earth is suited for life
● Earth is the only planet that we know of that can sustain life
● Also the only planet that has large amounts of liquid water on its surface
● The water on the earth’s surface is called the hydrosphere
● It moderates the temperature of the earth
● The hydrosphere and continents also holds an amazing diversity of life
The Atmosphere Protects the Earth from
Radiation and Sustains Life
Like the hydrosphere, the atmosphere helps moderate temperatures
● The greenhouse effect traps heat in the atmosphere, so earth’s surface doesn’t
freeze at night
● The earth’s atmosphere also protects us from ultraviolet radiation and high
energy particles from the sun, which are blocked in the upper atmosphere so it
doesn’t harm any life on earth, and space debris
● Earth is the only planet we know of that has enough oxygen to sustain complex
life
Mars
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Although no humans have been able to visit Mars yet, many probes have been sent to its
surface
The Pathfinder mission deployed a rover called Sojourner, which explored the surface using
robot navigation systems
Saw that mars contains small amounts of frozen water
Mar’s mass is 10% of Earth’s, it orbits the sun every 1.9 years, and a day lasts 24.6 hours.
The Martian volcano Olympus Mons is the largest mountain in the solar system
It is three times the height of Mount Everest
Grew from lava flows
Like the moon, mars has many craters, they impact the surface since Mars has a thin
atmosphere
Review Q’s
What is the order of the terrestrial planets?
The composition of the terrestrial planets is _____.
What is Mercury similar in appearance to?
The name of the mission that was sent to Mercury was
______.
What makes Venus very reflective?
The atmospheric layer of Venus contains ______.
Websites
http://abstract-artphotos.blogspot.com/2011/02/planet-earth.html
https://www.youtube.com/watch?v=7f0mhFimk4&feature=em-share_video_user
Outer planets (gas giants)
● Except for Pluto, the outer planets are much larger than
the inner planets.
● Inner planets contain thick, gaseous atmospheres with
many satellites and rings.
● Large planets are called Gas Giants.
● Gas Giants have no solid surface, which means a
spaceship can’t land on them
Jupiter (largest planet)
● Jupiter is big enough to hold 1300 Earths
● Jupiter takes about 12 Earth years to orbit the sun.
● Jupiters atmosphere contains clouds of hydrogen,
helium, methane and ammonia.
● In 1610, Galileo discovered the four largest of Jupiter’s
61 satellites, named Io, Europa, Ganymede, and
Callisto
All the gas giants have rings and
satellites
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The vast of Saturn’s rings were recognized in 1659.
Uranus’ rings were not discovered until 1977.
Jupiter contains 61 satellites
Saturn contains 31 satellites
Uranus contains 26 satellites
Neptune contains 13 satellites
Saturn has the most extensive ring
system
● Saturn is 95 times the mass of the Earth and takes over 29 years to orbit
the sun.
● Saturn's rotation is 10.7 hours. It rotates fastest at the equator and slower
near the poles.
● It's rings is made up of tiny particles of dust, rock, and ice.
● Many rings are 10 to 20 m thick.
● Competing gravitational forces from Saturn and a it's many satellites hold
the particles in place.
Uranus and neptune are blue giants
● The two planets are similar to each other in size and color
● The are large enough to hold thick,gaseous atmospheres composed of
hydrogen,helium and methane.
● Methane give the planets the bluish color
● William Herschel discovered Uranus by accident in 1781.
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Uranus is 14 of earth’s mass and it takes 84 y to orbit the sun
pg.644
Pluto--the oddball (no longer a planet)
● Percival Lowell used fluctuation in neptune’s orbit to predict another planet
● In 1930 Clyde Tombaugh found a planet close to his prediction called
pluto.
● Pluto’ s satellite, Charon-- not like other planets
● Some scientists believed that Pluto was captured by gravity of the sun.
● It takes 248 y to complete one orbit.
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Its mass is only 0.002 of earth’s mass
pg.645
https://www.youtube.com/watch?v=SCiQjJ2Jg1
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Quiz (T/F)
● Is Earth apart of the gas giants?
● Is Jupiter the second largest planet in the
solar system?
● Do all gas giant planets have rings and
satellites?
● Is Uranus and Neptune considered blue
giants?
Origin of the Solar System
Historians believed that many ancient astronomers watched the
change in the sky. Some ancient people told stories about the
movements of stars. Then as time moved on, tools for
mathematics were used to make models of observation for
astronomy-like objects. This caused the ancient people curiosity
to grow and make them wonder about the universe and the
creation of the Scientific Method.
Ch.19 pg.646
Models of the Solar System Pg. 647
1. The first model of the solar system was made by Ptolemy, I showed Earth
being in the center of the solar system (geocentric)
2. The second model, made by Nicolaus Copernicus, proposed a sun
centered system with the planets revolving in a perfect circle (heliocentric)
3. Newton came to explain it all however, with his theory that the
gravitational force that keeps planets in orbit around the sun, is the same
when we fall to Earth.
All planets orbit Sun in same direction & Sun rotates &
close to its equatorial plane. It was once thought that
moon,sun,& planets orbited Earth. Sun has 99.9% of solar
system mass.
Questions
1. Judging by the info given to you, what is the most similar solar system model to
our modern day diagram?
2. What was Newton’s theory about the gravitational force between planets?
3. What tool(s) do you think were used to help for observation of celestial bodies
(planets) and the measurements of models?
Videos
Here are some videos!
Birth of the Solar System - YouTube
https://www.yo
utube.com/wat
ch?v=0rHUD
WjR5gg
The Nebular Model
Pages 648-649
What is a Nebula?
➢ A Nebula is a large cloud of dust and gas in space.
➢ This is also a region where stars are born or where
stars explode at the end of their lives.
➢ A Nebular Model is a model for the information of the
solar system in which the sun and planets condensed
from a cloud of gas and dust.
➢ https://www.youtube.com/watch?v=UCp-XKeSvSY
Next the Nebula formed..
❖ After the cloud collapsed, it formed a flat rotating disk.
❖ In the center with warmer temperatures and higher
density, a star began to form.
❖ Because of the high speed that the Nebula spun, it
became flattened.
Now what happens?
❖ With the leftover matter in the Nebula, small planets
also known as Planetesimals form.
❖ This process is known as Accretion.
❖ The Nebular Theory explains how gas giants are
different from terrestrial planets. The newly formed
planets are capable of holding gases including helium
and hydrogen.
Quiz Time!
1. What is the definition of a Nebula?
2.) What is the definition of a Nebula Model?
3.) True or False: Accretion is the leftover matter
from Planets that form new ones
How did the moon form 653
in space over millions of years ago a Mars
sized star hit earth(just a molten rock), the
debris clumped together, and the moon began
to orbit the earth