Download The Solar System

The Solar System
The Solar System
 Main Idea:
 The Earth is one of eight planets in our Solar System and it rotates on its
axis every 24 hours and takes exactly a year to orbit the sun.
The Solar System
 Lecture Focus:
 Have you watched a sunrise or sunset and wondered why the Sun seems to move
across the sky each day…lets find out about Earth and its place in the solar system.
The Solar System
 The sun provides the heat necessary for life on our planet.
 Earth, the seven other major planets and thousands of smaller bodies all
revolve around the sun.
The Solar System
 Together with the sun and the other bodies form our Solar System.
 The Solar System - The collection of eight planets and their moons in orbit around the
sun, together with smaller bodies in the form of asteroids, meteoroids, and comets.
The Solar System
 You have probably heard that our Sun is located in the Milky Way galaxy…but
what is a galaxy anyway?
 Galaxies are large systems of stars, dust and gas bound together by
gravitational force…they are elliptical, spiral or irregular in shape…our Sun is
part of a spiral galaxy called The Milky Way.
The Solar System
 The Milky Way is the galaxy that contains our Solar System…its name "milky" is
derived from its appearance as a dim glowing band arching across the night sky in
which the naked eye cannot distinguish individual stars.
The Solar System
The Solar System
 Diagram Skills:
 Identify : 1) Which two planets are closest to the sun?
 Identify – 2) What two planets are furthest away from the sun?
The Solar System
 Diagram Skills:
 Identify : 1) Which two planets are closest to the sun?
 Mercury and Venus
 Identify – 2) What two planets are furthest away from the sun?
 Uranus and Neptune
Major Planets
 The major planets differ from one another in size and make up.
 The “Inner Planets” Mercury, Venus, Earth and Mars are relatively small and solid.
Major Planets
 The “Outer Planets” Jupiter, Saturn, Uranus and Neptune are extremely
large and composed mostly or entirely of gases.
Major Planets
 Our Solar System also has Dwarf Planets which is a object that is neither a planet nor a
moon in direct orbit of the Sun.
Major Planets
 Some astronomers expect there may be as many as 50 Dwarf Planets in the solar system.
Major Planets
 Pluto is the only dwarf planet to once have been considered a major planet.
 Once thought of as the ninth planet and the one most distant from the sun, Pluto is now
seen as one of the largest known member of the Kuiper Belt, a shadowy disk-like zone
beyond the orbit of Neptune populated by a trillion or more comets.
Major Planets
 Pluto was reclassified as a dwarf planet in 2006, a change widely thought of as
a demotion that has attracted controversy and debate.
Major Planets
 American astronomer Percival
Lowell first caught hints of Pluto's
existence in 1905 from odd
deviations he observed in the orbits
of Neptune and Uranus, suggesting
that another world's gravity was
tugging at them from beyond.
 He predicted its location in 1915, but
died without finding it.
 Its discovery came in 1930 from
Clyde Tombaugh at the Lowell
Observatory.
Major Planets
 Now each planet follows its own path, or Orbit, around the sun.
 The Orbits vary from nearly circular to elliptical or even oval shaped.
Major Planets
 Can anyone tell me how long it takes Earth to orbit the sun???
Major Planets
 The time necessary to complete an orbit differs as well.
 For example, Mercury needs only 88 days to circle the sun, Neptune however,
will make one complete orbit of the Sun every 165 years.
Major Planets
 Questions:
 1) What is the special name for the smaller, solid planets and what are their
four names?
 2) What is the special name for the larger, gas planets and what are their
four names?
 3) What does the term orbit mean?
Major Planets
 Questions:
 1) What is the special name for the smaller, solid planets and what are their
four names?
 The Inner Planets…Mercury, Venus, Earth and Mars
 2) What is the special name for the larger, gas planets and what are their
four names?
 The Outer Planets…Jupiter, Saturn, Uranus and Neptune
 3) What does the term orbit mean?
 A path a planet travels around the Sun
Earth’s Movement
 Earth takes almost 365 ½ days to make one revolution.
 Revolution – is a complete circuit or circle around the sun…this period is what we define
as one year.
Earth’s Movement
 Every four years, the extra fourths of a day are combined and added to the
calendar as February 29th.
 A year that contains one of these extra days is called a Leap Year.
Earth’s Movement
 As Earth orbits the sun, it rotates, or spins on its Axis.
 The Axis is an imaginary line that passes through the center of the Earth from
the North Pole to the South Pole.
Earth’s Movement
 Earth rotates in an easterly direction, making one complete rotation every 24 hours.
 As Earth turns, different parts of the planet are in sunlight or in darkness.
Earth’s Movement
 The part facing the sun experiences daytime and the part facing away from
the sun experiences nighttime.
Earth’s Movement
 Why do we not feel Earth moving as it rotates?
Earth’s Movement
 The reason is that the Atmosphere, the layer of oxygen and other gases that
surrounds Earth, moves along with it.
Earth’s Movement
 Questions:
 1) How many days does the Earth take to make one revolution?
 2) What is a Leap Year?
 3) What does the term Axis mean?
Earth’s Movement
 Questions:
 1) How many days does the Earth take to make one revolution?
 365 ½
 2) What is a Leap Year?
 A year that contains an extra day
 3) What does the term Axis mean?
 An imaginary line that the rotates on…it runs from the north Pole to the
South Pole
Earth’s Movement
 Reading Check:
 Please answer the following question in a well written open ended
response.
 Describe Earth’s two principal motions…Revolution and Rotation.
History Mystery Time
 IT’S A HISTORY MYSTERY!!!!!
History Mystery Time
 Thousands of years ago, ancient civilizations turned to the heavens, marveling
at their wonders.
 These ancient people worshipped various gods and often linked their gods with
planets in the sky, which they considered to be “wandering stars.”
History Mystery Time
 Our Solar System takes their names from
Roman Mythology which is a variation of
Greek Mythology.
 Essentially when the Greek Empire
collapsed, much of their culture traveled to
Rome, including their Religious ideas.
.
History Mystery Time
 Mercury (Greek Equivalent Hermes) gets its name from the winged messenger
of the gods…he was also the god of thievery, commerce, and travel.
 Most likely, the planet got its name from the rate at which it spins…it only takes
88 days for the planet to rotate around the sun
History Mystery Time
 Venus (Greek Equivalent Aphrodite) was the Roman goddess of love and beauty, so it
is a fitting name for this brightly shining planet…the only objects in our Solar System
brighter than Venus are the Sun and the Moon.
 Ancient civilizations thought that Venus was two different objects – the Morning Star and
the Evening Star, other civilizations have also associated the planet with love. The
Babylonians called the planet Ishtar after their goddess of love.
History Mystery Time
 Earth is the only planet not named after a Roman god or goddess, but it is
associated with the goddess Terra Mater (Gaia to the Greeks).
 In mythology, she was the first goddess on Earth and the mother of
Cronus…the name Earth comes from Old English and Germanic “eorthe” and
“ertha,” which mean “ground.”
History Mystery Time
 Mars (Greek Equivalent Ares) is named after the Roman god of war.
 The planet got its name from the fact that it is the color of blood.
History Mystery Time
 Jupiter (Greek Equivalent Zeus) was the Roman king of the gods.
 Considering that Jupiter is the largest planet in our Solar System, it makes sense that the
planet was named after the most important god.
History Mystery Time
 Saturn (Greek Equivalent Cronus) was named after the Roman god of
agriculture and harvest...while the planet may have gotten its name from its
golden color, like a field of wheat, it also had to do with its position in the sky.
 According to Roman Mythology, the god Saturn stole the position of king of the
gods from his father Uranus…the throne was then stolen by Jupiter.
History Mystery Time
 Uranus (Roman Equivalent Caelus) was not discovered until the 1800’s, but the astronomers
in that time period continued the tradition of naming planets after Roman gods.
 In mythology, Uranus was the father of Saturn and was at one time the king of the gods…He is
also the “Sky” in Greek Mythology and is married to Gaia.
History Mystery Time
 While Neptune (Greek Equivalent Poseidon) almost ended up being named
after one of the astronomers credited with discovering it, Verrier … that was
greatly disputed, so it was named after the god of the sea.
 The name was probably inspired by its blue color.
History Mystery Time
 Pluto (Greek Equivalent Hades) is no longer a planet, but it used to be…the dark, cold,
former planet was named after the god of the underworld.
 The first two letters of Pluto are also the initials of the man who predicted its existence,
Percival Lowell…it has nothing to do with the dog!
History Mystery Time