Transcript ESSR_PNE_PlanetsMoon_V01m

Planets of the Solar System
The Moon and Other Bodies
Formation of the Solar System
• The Solar Nebular Theory
• Describes the origin of our solar system
• The Big Bang describes the origin of the universe
• After the Big Bang, clouds of gas and dust formed
nebulas
• Nebulas are the beginning of all new stars.
• Gravity caused the gas and dust to begin to condense,
collide, and heat up
• When the temperature gets hot enough, nuclear fusion
begins; the sun was born ~5 billion years ago
The Inner Planets (4) - The terrestrial planets
• Mercury:
• Smallest planet, no satellites
• Venus:
• Venus rotates on its axis opposite all the other planets.
This is known as retrograde rotation.
• Venus is very hot due to runaway greenhouse effect.
The Inner Planets
• Earth:
• The only planet with liquid water and life
• Mars:
• One Day = One Earth day – Even though Mars is smaller
than Earth, one rotation is equal on both planets
• The largest volcano in the solar system is on Mars. The
name of the volcano is Olympus Mons
The Outer Planets (the gas giants)
• Jupiter:
• The largest planet, biggest diameter, and its mass is
twice all the other planets combined; diameter is 11
times Earth’s diameter
• “Giant Red Spot” is the most unique feature of Jupiter’s
surface; massive storm similar to a hurricane
• Saturn:
• Complex ring system, least dense planet
The Outer Planets (continued)
• Uranus:
• Green color caused by methane in the atmosphere
• Planet is tilted 90˚
• Neptune:
• Farthest planet from the sun
• Bluish-green color with white “clouds” of frozen methane
• Pluto:
• No longer considered a planet
• Discovered by accident in 1930
The Earth-Moon System
Lunar Rotation
• The moon’s revolution around Earth (29.5 days) and its
rotation on its axis (29.5 days) are equal.
• The part of the moon illuminated by sunlight that we can
see from Earth changes as the moon orbits Earth causing
phases of the moon.
Phases of the Moon
Eclipses
eclipse an event in which the shadow of one celestial
body falls on another
• The Earth / Moon system experiences two types of
eclipses; solar and lunar
Solar and Lunar Eclipses
Tides on Earth
• Bulges in Earth’s oceans, called tidal bulges, form
because the moon’s gravitational pull on Earth.
• As a result, the ocean on the side of the Earth closest to
the moon is pulled toward the moon.
• Because Earth rotates, tides occur in a regular cycle at any
point on Earth’s surface each day as the location passes
through a tidal bulge or moves away from a tidal bulge.
Causes of Tides
Timing of Tides on Earth
Asteroids
• Asteroids = Fragments of rock which orbit the sun
• Asteroids are made of the same materials the planets are
composed of
• Most asteroids exist in a belt between Mars and Jupiter
Comets
• Comet = A body of rock, dust, methane, ammonia,
and ice which orbits the sun in long ellipses
• Comets have a head and a tail
• Comets lose mass as they orbit the sun because ice
melts when the comet is near the sun
• The most famous comet is Halley’s comet. The comet
can be seen every 75-76 years from Earth
Halley’s Comet
Image of Halley’s Comet taken from the Mount Wilson
Observatory.
Halley’s Comet will not be visible from Earth again until 2061.
Meteroids
• Meteoroids = small bits of rock and metal which
move randomly through the solar system
• Meteor = a meteoroid which enters the Earth’s
atmosphere
• Meteorite = any part of a meteor which remains after it
hits the Earth’s surface