Our Solar System

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Our Solar System

• Introduction and Key Terms

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Learning Outcomes (Students will)-Explain the
theories for the origin of the solar
system-Distinguish between questions that can
be answered by science and those that cannot, and
between problems that can be solved by technology
and those that cannot with regards to solar
system formation.-Estimate quantities of
distances in parsec. Estimate the age of the
solar system. -Describe and apply
classification systems and nomenclature used in
the sciences. Classify planets as terrestrial
vs. Jovian, inner vs. outer, etc. Classify
satellites. Classify meteoroid, asteroid, dwarf
planet, planet. Classify comets as long period
vs. short period. etc -Formulate operational
definitions of major variables. Given data such
as diameter and density describe the properties
that divide the planets and moons into
groups.-Tools and methods used to observe and
measure the inner and the outer planets and the
minor members of the solar system
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Planetary Systems

• A planetary system consists of the various
  non-stellar objects orbiting a star such as
  planets, dwarf planets, moons, asteroids,
  meteoroids, comets, and cosmic dust.

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Solar System

• A specific planetary system around our star
• The region of space that falls within the
  gravitational influence of our Sun
• If you consider the edge of the Solar System to
  be Plutos orbit, the Solar System has a diameter
  of 79 AU
• Consists of
• an ordinary yellow star the Sun
• Eight Planets
• Their moons
• Dwarf planets
• Asteroids, Comets, Meteors and Meteorites
• Cosmic dust

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Star

• A star is a massive, luminous ball of plasma that
  is held together by gravity.
• Our star is the Sun
• The gravity on the Sun is 274 m/s2

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Planets

• There are now 8 planets in our Solar System
• The Sun is one of the foci for each of these
  planets

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What is a Planet?

• Former definition NASA (2000)
• Planet A non-luminous celestial body larger than
  an asteroid or comet, illuminated by light from a
  star, such as the sun, around which it revolves.
• What is wrong with this definition?
• Why did the definition change?

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New definition NASA (2006)

• A planet is a celestial body that
• (a) is in orbit around the Sun,
• (b) has sufficient mass for its self-gravity to
  overcome rigid body forces so that it assumes a
  hydrostatic equilibrium (nearly round) shape, and
  
• (c) has cleared the neighbourhood around its
  orbit.

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Classifying Planets

• Planets can be classified by
• 1) Composition
• 2) Size
• 3) Proximity to the Sun
• 4) Position relative to Earth
• 5) History

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1) Composition

1. Rocky or Terrestrial planets (4)
2. Jovian planets (4)

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Terrestrial Planets

• Composed primarily of rock and metal
• No rings
• Few satellites (moons)
• High density
• Slow rotation
• Solid surface

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Jovian Planets

• Composed primarily of gas (hydrogen and helium)
• Rings
• Many satellites (moons)
• Low density
• Rapid rotation
• Deep atmospheres

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2) Size

1. Small planets (4)
2. Giant planets (4)

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Small Planets

• - Diameters less than
• 13,000 km

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Giant Planets

• - Diameters greater than
• 48,000 km
• - Also called gas giants

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3) Proximity to Sun

• Inner planets (4)
• Outer planets (4)
• The asteroid belt between Mars and Jupiter forms
  the boundary between the inner solar system and
  the outer solar system.

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4) Position relative to Earth

• Inferior planets (2)
• Earth
• Superior planets (5)

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Inferior Planets

• Closer to the Sun than Earth
• Show phases like the Moons when viewed from Earth

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Superior Planets

• Farther from the Sun than Earth
• Always appear full or nearly full

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5) History

• Classical planets
• Modern planets
• C) Earth

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Classical Planets

• Known since prehistoric times
• Visible to the unaided eye (no telescope needed)
• In ancient times this term also referred to the
  Sun and the Moon

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Modern Planets

• Discovered in modern times
• Visible only with optical aid or telescope

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What is a Dwarf Planet?

• NASA (2006)
• A dwarf planet is a celestial body that
• is in orbit around the Sun,
• has sufficient mass for its self-gravity to
  overcome rigid body forces so that it assumes a
  hydrostatic equilibrium (nearly round) shape,
• has not cleared the neighbourhood around its
  orbit, and
• is not a satellite.

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SHAPE
Ceres (dwarf planet) Photo Hubble Space
Telescope
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(No Transcript)
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Dwarf Planets

• Pluto (direct observation)
• Ceres (direct observation)
• Discovered in 1801!!!
• Classified as a planet for 50 years
• Demoted to asteroid
• Promoted to dwarf planet
• Eris (larger than Pluto)
• Discovered in 2005
• Controversial decision regarding Pluto

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Dwarf Planets

• Makemake and Haumea are determined to be dwarf
  planets using mathematical calculations

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Other Celestial Bodies in Our Solar System

• All objects besides planets and dwarf planets,
  except satellites, orbiting the Sun shall be
  referred to collectively as Small Solar-System
  Bodies.
• Some small Solar-System bodies include
• Asteroids
• Comets

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Asteroids

• An asteroid (or minor planet)
• (a) orbits the Sun inside the orbit of Jupiter
• (b) does not have sufficient mass for its
  self-gravity to overcome rigid body forces so
  that it assumes a hydrostatic equilibrium shape
  (it is not round shaped),
• (c) has not cleared the neighborhood around its
  orbit, and
• (d) is not a satellite.

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SHAPE
Vesta (asteroid or minor planet)
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(No Transcript)
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Clearing the Neighborhood

• There are very few other objects in the vicinity
  of Jupiter and the inner planets that orbit the
  Sun.
• Vesta and Ceres have many other asteroids in
  relatively nearby orbits.

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(No Transcript)
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Key Terms

• 1) Draw a diagram for each with labels to show
  the difference between a planet, dwarf planet and
  asteroid.
• 2) Create a metaphor or analogy for comparison.

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3) Create a Venn Diagram for these three terms.
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1) DecidePlanet, Dwarf Planet or Asteroid?
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2) DecidePlanet, Dwarf Planet or Asteroid?
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3) DecidePlanet, Dwarf Planet or Asteroid?
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4) DecidePlanet, Dwarf Planet or Asteroid?
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5) DecidePlanet, Dwarf Planet or Asteroid?
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6) DecidePlanet, Dwarf Planet or Asteroid?
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7) DecidePlanet, Dwarf Planet or Asteroid?
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8) DecidePlanet, Dwarf Planet or Asteroid?
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http//www.dawn-mission.org/dawnclassrooms/dwarf_p
lanet/TG_dwarf_planet.pdf

• Answers
• 1 p
• 2 dp
• 3 not enough info dp or a
• 4 a not round
• 5 a
• 6 p
• 7 a
• 8 none not in right place!

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New English Words

• Plutoed
• Ceresed