Moons

 Many moons in our Solar System  They have craters, volcanoes, possibly underground oceans A radar mapping image made by the Cassini spacecraft of a flyover area on Saturn's giant moon Titan showing an ice volcano

Satellites  Natural (not man made) or artificial bodies that revolve around larger bodies such as planets are called satellites  Mercury and Venus have no natural satellites  All other planets have moons (satellites)

Our Moon 1. What are the light colored areas? 2. What are the dark colored areas?

Answers 1. Highlands that have been impacted by craters (in the past) 2. Lowlands that were impacted by craters… then filled in with lava from beneath the moons surface (no longer has lava)

Mapping the moon  Neil Armstron g, Buzz Aldrin, and Michael Collins landed on the Sea of Tranquilit y on July 20, 1969

What is it like on the moon?  No air  No oceans (water)  No clouds  No life  Less gravity 5/6 (83%) less If you weigh 100 pounds on Earth  you would weigh 16.6 pounds on the moon  Lots of dust

Is the moon far away from Earth?  Yes… and no  It’s the closest object to us in the solar system  Avg. distance from Earth is 380,000 km (236,121 miles)  It takes about 3 days in a rocket ship  It would take 3 weeks if you were traveling at 500 mph

How big is the moon?

How heavy is the moon?

Luna: The Moon of the Earth  Solar system is 4.6 billion years old  Based this data from lunar rocks brought back from Apollo mission

Surface of the Moon  Impact craters on the moon tell the age of the moon  If the surface is young, there hasn't been time for many craters to form  Different parts of the surface of the Moon exhibit different amounts of cratering and therefore are of different ages

How did the moon form?  Giant Impact Theory

Lunar Origins  Formation of the moon happened in three steps  1 st Impact – large body collided with earth, blasted part of Earth’s mantle in space  2 nd Ejection – sent mantle debris from Earth and from impacting body (including its iron core)  3 rd Formation – debris orbited around Earth and began to join together

Moon Formation 

Phases of the Moon  /animations/content/moonphase.html /animations/content/moonphase.html  Waxing – sunlit fraction is getting larger  Waning – sunlit fraction is getting smaller  Moon always gets same amount of sun( same as Earth)  You always see same side of the moon

Phases of the Moon  Appearance of the moon from its changing position relative to Earth and the sun  As moon revolves around Earth, amount of sunlight on the side of the moon that faces Earth changes  Called Phases

Waxing and Waning  Waxing – sunlit fraction is getting larger  Waning – sunlit fraction is getting smaller  Crescent – croissant shaped or fingernail clipping  Gibbous – bulging outward

Phases

Tides  Caused by the moons gravity  Pulls on the water toward the moon High tide  Opposite side also high tide Moon’s gravity also pulls on the center of the Earth

High tide vs Low tide

Spring Tides  You always have two high tides and two low tides  Spring Tides have nothing to do with the season.  Spring tides happens when moon is full or new – when sun and moon are aligned  Spring tides = very high and very low tides

Spring Tide  When the sun, moon, and Earth are in alignment during a new or full moon  extra-high high tides, and very low, low tides

Spring Tide  During each lunar month, two sets of spring and two sets of neap tides occur

Neap Tides  Happens when sun and moon are NOT aligned  Happens during quarter phases  Gravitational forces cancel each other out  This canceling of forces causes the tides to not be dramatically low or high

Neap Tide  sun and moon are at right angles to each other  the solar tide partially cancels out the lunar tide  produces moderate tides known as neap tides

Neap Tide  Caused by the moons gravity  Pulls on the water toward the moon High tide  Opposite side also high tide Moon’s gravity also pulls on the center of the Earth

Eclipses – two types  Solar  Lunar

How does a lunar eclipse happen?  Moon passes directly behind Earth…  …In its shadow  Penumbra- Lighter part of the shadow  Umbra- Darkest part of Earth’s shadow

Penumbra to Umbra  Total eclipse- Moon passes completely into the umbra  Partial eclipse- Moon misses all or part of the umbra Penumbra Umbra

Why does the moon appear red?  The moon appears red because light bends around earth.  Red wavelengths of light are the longest… only ones to reach the moon

How does a solar eclipse happen?  Solar eclipse- Moon passes directly between the sun and Earth  Casts a shadow onto Earth’s surface

Partial solar eclipse  The moon covers only part of the sun  Can still see the sun

Isn’t the moon to small to block the sun?  Total solar eclipse  The moon is 1/400 the size of the sun…  …but it is so much closer to us that it appears large…  …large enough to block the sun

Tilted Orbit of the Moon  Why don’t you see solar and lunar eclipses every month?  Moon’s orbit around Earth is tilted by about 5 degrees.  Just enough to place moon out of Earth’s shadow for most full moons and Earth out of the moon’s shadow for most new moons. Get some Sun Smile once in a while Lay off the Steroids.