Chapter 27 Notes
The Planets and the Solar System
Inner Planets – TERRESTRIAL (made up of rock:) Mercury, Venus, Earth and Mars
Mercury
Most extreme temperature range
No atmosphere – very hot day and very cold night
Very densely cratered – Mercury has very little to no atmosphere to protect it from being hit by meteors/asteroids
Venus
Earth’s Twin – similar in size
Extreme Greenhouse Effect – Lots of CO2 in atmosphere (from volcanoes) – ALWAYS HOT!!!!!
Evening Star
Morning Star
Earth
Water Planet, Only planet with Oxygen, Only planet with humans and life
Mars
Red planet – due to FeO2 on the surface
Polar ice caps – made of frozen CO2
Mars landers – Spirit and Opportunity
New lander
Outer Planets – JOVIAN (made up of gas): Jupiter, Saturn, Uranus, and Neptune
Jupiter
Largest planet, Great Red Spot – hurricane like storm, Fastest rotation
Jupiter’s Moon Io has an active volcano!
Saturn
Great ringed planet
Uranus
Rotates completely on its side
Neptune
Blue due to the presence of methane
Pluto
No longer a planet
A dwarf planet – too small
Crossed the orbit of another planet (Neptune)
Asteroid Belt
Separates the Inner planets and the outer planet

Planetary Satellites
Satellite - A body that orbits another body
Natural satellites are moons
6 of the 8 planets have at least one moon
Mercury and Venus do NOT have a moon
Earth
1 moon
Mars
2 moons - Phobus & Deimos
Jupiter
At least 28 moons -4 largest are Io, Ganymede, Europa and Callisto
Saturn
24 moons - Largest is Titan
Uranus
21 moons - 5 major moons are Titania, Oberon, Umbriel, Ariel and Miranda
Neptune
8 moons - Triton is the largest
Pluto
1 moon - Charon – almost the same size as Pluto
Solar System Debris
Comets - A mixture of dust, gas and ice that orbits the sun
Nicknamed “dirty snowballs”
Haley’s comet comes around every 76 years, last seen in 1986
Coma (ice and dust) and a tail (gas)
Comets orbit the sun - The tail of the comet gets “blown” away by the solar wind
Asteroids
Solid, rock-like fragments orbiting the sun between Mars and Jupiter
Meteoroids
Icy, rocky fragments anywhere in space
Meteors
Meteoroids that enter Earth’s atmosphere and begin to “burn” due to the presence of oxygen
Meteor Showers - “shooting stars”
Meteorites: A meteoroid that survives the trip through our atmosphere and actually impacts the Earth’s surface, forming impact craters