What is the Solar System? “The Players” An Overview of the Solar System Classification Size, density, & atmosphere Terrestrial – Earth like Giant (Jovian) – Jupiter like Table 15.1 (p. 382) AU (Astronomical Unit) = 93 million miles Inclination to ecliptic Period of Rotation Period of Revolution Mass Relationship of distance and revolution

Mercury – “The Winged Messenger” Small planet 8 th largest Seen as a “morning star” or “evening star” Fig p. 382 Heavily cratered Very very hot 825 degrees F Very very cold -320 degrees F Weak gravitational pull (mass) No atmosphere No natural satellites (moons)

Mercury

Venus – The “Goddess of Beauty” Earth’s “sister planet” Evening & Morning star Brightest of all planets A “blueish” color Thick dense atmosphere Phases Day vs. Year Rotates – 243 days Revolves – 225 days Tilt of axis (177 degrees) Rising & setting of the Sun (west to east) Retrograde rotation High atmospheric pressure 100x that of Earth 1,070 lbs/sq. in. CO2 (97%) Massive “greenhouse effect” Rains sulfuric acid

Venus

Mars – The “God of War” Very Earth like Distinct “reddish” color Interesting features: The plains The “channels” Dried river beds Martians and other good stories Seasonal changes Polar ice caps Frozen CO2 Olympus Mons volcano 15 mi. high 370 mi. wide The size of Texas

Atmosphere 95% CO2 Phobos & Deimos (The Gods of Fear & Panic) Small in size Irregular in shape

Mars

Olympus Mons

Phobos

Demos

Jupiter – King of the Gods By far the largest planet in the Solar System 318 x’s that of Earth 11x’s the diameter Interesting features: Great Red Spot 25,000 mi dia. A Jovian storm Colorful bands (Fig. 15.9) 39 satellites Galilean Satellites Io  Erupting volcano Europa Callisto Ganymede Atmosphere H & He Ring structure

Jupiter

Moons of Jupiter

Saturn – God of Agriculture Visible in the night sky The planet with “ears” Interesting Features: A system of rings (Fig p. 391) Pieces of frozen CO2, rock, etc. 2 nd largest planet in the Solar System The end of the “Ancient Planets”

Saturn

Saturn – Rings edge on

Titan, Saturn's largest moon, looks small next to the gas giant in this Cassini spacecraft view. Titan (3,200 miles across) is in the upper right. (USA Today – 3/5/12)

Uranus & Neptune Twin planets The “Ice Giants” Atmosphere – H & He Uranus – God of the Sky A bit of history Discovered in 1781 William Hershel – a comet hunter Neptune – God of the Sea A bit of history Discovered in 1846 Adams & Leverrier Noticed variations in orbital path

Uranus

Neptune

Pluto – God of the Underworld Discovered in 1930 American astronomer Clyde Tombaugh Interesting Features: Moon discovered in 1978 Charon Named for the boatman who ferried dead souls across the river Styx Very inclined orbit – 17 degrees

Asteroids, Meteors & Comets Comets Cosmic “ dirty snowballs” Highly eccentric orbits Head or Coma & a tail Tail always points away from the Sun  Force of solar wind Between Mars & Jupiter sublimation begins Years to complete 1 orbit Best known Halley’s Comet  76 yr orbital period Form in what is known as Oort’s Cloud 30 AU – 1 ly Comets give birth to meteors (Shooting Stars)

Bayeux Tapestry Battle of Hastings 1066 AD

Asteroids Know as the Asteroid Belt Located between Mars & Jupiter Vary in size Average ~ 30 mi. Meteoroids, Meteors, & Meteorites Location, Location, Location By product of comets “Shooting Stars” Meteor showers Table 15.5 p. 392 Interact (friction) with upper layers of atmosphere and burn up

Composition of Meteors Iron Stone Iron-stone

Bode’s Rule Number Planet T.D. (AU) (0 + 4) / Mercury.39 (3 + 4) / Venus.72 (6 + 4) / Earth 1.0 (12 + 4) / Mars 1.5 (24 + 4) / ????? 2.78 (48 + 4) / Jupiter 5.20 (96 + 4) / Saturn 9.58 ( ) / Uranus 19.2 ( ) / Neptune 30.1 ( ) / Pluto 39.5

Protoplanet Nebular Model 5 billion years ago Born out of the death of ancient stars “cosmic dust” & debris begins to concentrate in a cloud-like (Nebula) environment Concentrated mass begins to rotate Central area gives birth to a new star (Sun) Cosmic debris begins to concentrate as planets begin to take shape