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Mr. Vallee’s
Introduction to the Solar System
Student Handout
http://www.brainpop.com/science/
http://science.nationalgeographic.com/science/space/solar-system
http://www.jpl.nasa.gov/solar_system/index.cfm
http://spaceplace.jpl.nasa.gov/
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General Introduction to the Solar System. The words "solar system"
refers to the Sun and all of the objects that travel around it. These
objects include planets, dwarf planets, natural satellites such as the
moon, the asteroid belt, comets, meteoroids, and interplanetary dust
and gas. Our solar system has an elliptical shape and is part of a
galaxy known as the Milky Way. The Sun is the center of the solar
system. It contains 99.8% of all of the mass in our solar system.
Consequently, it exerts a tremendous gravitational pull on planets,
dwarf planets, satellites, asteroids, comets, and meteoroids.
How the solar system was formed. Astronomers believe the solar
system formed about 4.7 billion years ago. However, they differ in
their beliefs about how it formed. Most astronomers believe that solar
system formed from a single flat cloud of gas (hot hydrogen and
helium gas) known as the solar nebula.
Perhaps triggered by a nearby supernova or by the gravitational
disturbance of a passing star, the solar nebula began to contract and
rotate. Its central region collapsed into a protostar (a heavy hot core)
which began to grow. In the broad disk surrounding the protostar,
particles began to condense from knots of gas. These grew into bodies
of rock and ice a few miles apart. These collided and coalesced (came
together) and eventually formed planets. Although there are other
theories, this is the one believed by most astronomers.
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/solar_system.html
A. History (Beginning of Astronomy)
1. Theories about Earth
a. Shape: flat versus spherical.
(1) Aristotle watched eclipse of moon (partial obscuring of
one heavenly body by another) and noticed shadow of earth
on the moon was curved.
b. Position in the universe.
(1) Geocentric – earth is the center of the universe
(2) Heliocentric – sun is the center of the universe and it
spins on an axis. Early times, only Aristarchus believed
that.
(3) 1500s, Nicholas Copernicus believed heliocentric theory,
but church against that idea, so he recanted his belief. Kepler
“Father of Astronomy” had 3 important theories
(mathematical) as to “why/how planets move in relation to
sun.
2. Galileo – used telescopes for star gazing
3. Einstein’s theories how the universe works
4. Today, missions into space, telescopes, satellites orbiting in
space all give us continually updated information as to the
occurrences in our universe as well as others.
B. Our Solar System
1. Consists of celestial bodies (relating to the skies/heavens) that
revolve around our star, the sun. Includes:
a. Planets and their satellites/moons
(1) Planet must:
a. orbit the sun
b. must not be a satellite
c. must be massive enough for its own gravity to
keep it round, and also big enough to dominate its
orbit. Pluto falls short, as well as other orbiting
bodies that occupy the Kuiper belt.
b. Moons/satellites: maintain an orbit around their planet
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/planets.html
c. Dwarf Planet - an object that does not fit the planet category
(note the criteria above) – an example is Pluto, which fits all
criteria except for the last.
(1) Dwarf Planets must:
a. in orbit around the sun
b. has sufficient mass for its self-gravity to
overcome rigid body forces so that it assumes a “nearly
round” shape (hydrostatic equilibrium)
c. has not cleared the neighbors around its orbit
d. is not a satellite
d. Asteroids (millions of rocky lumps orbiting between Mars,
Jupiter)
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/asteroids.html
e. Meteors (rocks captured by Earth’s gravity, heated up by
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friction and burn)
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/meteoroids.html
f. Comets (billions of masses of dust and frozen gasses which
glow when they approach the sun). They originate in the Oort
cloud and the Kuiper belt.
http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/comets.html
g. Interplanetary dust and gas (left over particles/gas from
the origin of the solar system).
h. Sun - huge ball of hot gases that give off great amounts of
energy which comes from a nuclear reaction that takes place
inside of stars.
2. Movement of planets, dwarf planets, and satellites that orbit the
sun
a. The sun is the center of the solar system (show
diagram/basketball)
b. System is flat (show side view)
c. Each planet has its own orbit it follows around the sun
Mercury has an inclined orbit. The Dwarf planet, Pluto, has
the most elliptical orbit, although it is the furthest away from
the sun, there are 20+ years it is actually closer to the sun
than Neptune.
d. Travel counterclockwise around sun (all)
e. Travel different speeds
f. Planet year – time it takes to orbit the sun once (Pluto lasts
248 Earth years)
g. Planets spin as they orbit the sun. All spin counterclockwise,
except Venus (clockwise) and Uranus (spins on its side).
h. Planet day- time it takes to spin once on its axis.
3. Size of planets (huge difference)
a. Jupiter is 63 times bigger than the dwarf planet, Pluto
b. Sequence of planets in size from smallest to largest:
Mercury, Mars, Venus, Earth, Neptune, Uranus, Saturn, Jupiter.
4. Location from the sun (approximate scale to provide a
perspective ONLY):
Mercury 4”, Venus 7”, Earth 10”, Mars 15”, Jupiter 4’6”,
Saturn 8’, Uranus 16’, Neptune 25’
5. Inner planets (4) are Mercury, Venus, Earth, and Mars. Small
rocky worlds w/metal cores and except for Mercury they have
thin atmospheres.
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6. Outer planets (4) are Jupiter, Saturn, Neptune, and Uranus the gas giants. They have a deep atmosphere that thickens into
a hot liquid, which reaches to rocky cores. They all have rings
as well.
7. Dwarf planets (5). Pluto (located beyond Neptune), Ceres
(located in asteroid belt between Mars and Jupiter), Eris,
Makemake, and Haumea ( all located beyond Pluto in Kuiper
Belt). There are many more waiting to be identified!
8. Satellites/moons orbit every planet except for Mercury and
Venus.
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