Our Solar System

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Our Solar System
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EARLY IDEAS that are Not true!

• SUN, PLANETS, AND STARS ORBITED A STATIONARY
  EARTH meaning Earth centered or Geocentric.

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Retrograde Motion

• Is when a planet does not move east like it
  normally would in relation to Earth

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Nicolaus Copernicus

• Stated the Sun was the center of the Solar
  System. Meaning Sun-centered or
  Heliocentric.
• This model explained Retrograde Motion.

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Keplers First Law

• Each planet orbits the sun in a shape called an
  ellipse versus a circle.

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Astronomical Unit

• 1.496 x 108 1 astronomical unit. This is the
  average distance between the Sun and each planet!

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Eccentricity

• The Shape of a planets elliptical orbit!

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Perihelion

• When a planet is closest to the Sun in its orbit.

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Aphelion

• When a planet is farthest away from the Sun.

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Orbital Period

• The length of time it takes for a planet or other
  body to travel a complete elliptical orbit around
  the Sun

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Keplers Second Law

• Because a planet moves fastest when close to the
  Sun and slowest when far from the Sun, equal
  areas are swept out in equal amounts of time.

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Keplers third Law

• A mathematical problem between the size of a
  planets ellipse (a) and its orbital period (P).
  He found that the square of the orbital period
  (P) equals the cube of the semimajor axis of the
  orbital ellipse (a).
• P2 a3
• P is a unit of time measured in Earth years.
• a is a unit of length measured in astronomical
  units.

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In addition to Keplers Ideas,

• Galileo was the first person to use a telescope
  to observe the sky!
• He supported Copernicuss idea of the
  heliocentric model.
• He found that 4 moons orbited Jupiter.

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Lastly, we have Isaac Newton!

• He developed an understanding of gravity

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Newtons Findings

• Law of Universal Gravitation

• Center of Mass

• Every pair of bodies in the universe attract each
  other with a force that is proportional to the
  product of their masses and inversely
  proportional to the square of the distance
  between them.

• Each planet orbits a point between it and the Sun
  called the Center of Mass.
• This is the balance point between two orbiting
  bodies, similar to a pivot point on a see-saw.

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Our Solar System

• Our solar system is made up of
• Sun
• Eight planets
• Their moons
• Asteroids
• Comets

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Inner Planets AKA Terrestrial Planets

• From closest to farthest to the sun
• Mercury
• Venus
• Earth
• Mars

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Mercury

• Planet nearest the sun
• Second smallest planet
• Covered with craters
• Has no moons or rings
• About size of Earths moon
• No atmosphere

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• Sister planet to Earth
• Has no moons or rings
• Hot, thick atmosphere
• Brightest object in sky besides sun and moon
  (looks like bright star)
• Covered with craters, volcanoes, and mountains
• Has clouds of sulfuric acid.

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Earth

• Third planet from sun
• Only planet known to have life and liquid water
  (solid, liquid, and gas).
• Atmosphere composed of Nitrogen (78), Oxygen
  (21), and other gases (1).

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As you know. Earths axis is tilted

• Earths axis is wobbling like a toy top that
  wobbles if you give it a small sideways push
  while it is spinning. This wobble in the earths
  rotational axis is the PRECESSION!!

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Mars

• Fourth planet from sun
• Appears as bright reddish color in the night sky
  because of its high content of iron in the soil
• Surface features volcanoes and huge dust storms
• Has 2 moons Phobos and Deimos

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Outer Planets AKA Gas Giant Planets

• The outer planets are larger, more gaseous, and
  lack solid surfaces
• These are farthest from the Sun.
• Jupiter
• Saturn
• Uranus
• Neptune

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Jupiter

• Largest planet in solar system
• 5th planet from Sun
• Brightest planet in sky
• 60 moons, 5 visible from Earth
• Giant red spot
• Has belts (low, warm, dark-colored clouds that
  sink
• Has zones (high, cool, light-colored clouds that
  rise)

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Saturn

• 6th planet from sun
• 2nd largest
• Beautiful set of rings composed of ice and rock
• 31 moons
• Largest moon, Titan
• Easily visible in the night sky

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Uranus

• 7th planet from sun
• Rings are dark, almost black
• 27 known moons
• Uranus sits on its side with the north and south
  poles sticking out the sides.

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Neptune

• 8th planet from sun
• 7 known moons
• Triton largest moon
• Great Dark Spot A Storm!

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Our Dwarf Planet, Pluto

• Today, Pluto is called a "dwarf planet." A dwarf
  planet orbits the sun just like other planets,
  but it is smaller. A dwarf planet is so small it
  cannot clear other objects out of its path.
• Pluto was not really a planet because of its size
  and location in space

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Pluto

• Orbits very slowly
• Cold
• Covered in Ice

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How did our solar system form?

• Many astronomers HYPOTHESIZE that our solar
  system began from interstellar clouds (clouds of
  gas and dust).
• The interstellar clouds begin to move quickly as
  it becomes more dense at its center.
• It begins to spin faster and faster.
• The cloud begins to collapse and fall flat and
  becomes a rotating disk with a dense
  concentration at its center.

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Sun and Planet Formation

• The disk of dust and gas that formed the Sun and
  planets is knows as the SOLAR NEBULA.
• The dense concentration at the center became the
  Sun.
• Eventually, the condensation of materials into
  liquid and solid formed slowly forming planets
  that were warmer toward the sun and cooler away
  from the sun.

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The Growth of Objects

• Once the condensation slowed, the tiny grains of
  condensed material started to accumulate and
  merge together to form larger bodies called
  PLANETESIMALS.
• Planetesimals collided and merged and formed
  Planets!!

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Asteroids

• Small bodies
• Believed to be left over from the beginning of
  the solar system billions of years ago
• 100,000 asteroids lie in belt between Mars and
  Jupiter
• Largest asteroids have been given names

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Pieces of Asteroids

• Meteroid When a piece of an asteroid falls
  toward Earth and enters Earths atmosphere.
• Meteor The streak of light from a meteroid.
• Meteroite When the Meteroid hits the ground.

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Comets

• Small icy bodies
• Orbit the Sun
• Give off gas and dust as they pass by
• Coma The head of a comet
• Nucleus The small solid core