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The Moon. Notes 12-3. What is the Moon?. A natural satellite The only moon of the planet Earth. Location, location, location!. About 384,000 km (240,000 miles) from Earth 3,476 km (2,155 miles) in diameter (about ¼ the size of Earth). The Moon’s Size.
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The Moon Notes 12-3
What is the Moon? • A natural satellite • The only moon of the planet Earth
Location, location, location! • About 384,000 km (240,000 miles) from Earth • 3,476 km (2,155 miles) in diameter (about ¼ the size of Earth)
The Moon’s Size • The moon is 3,476 km in diameter, a little less than the distance across the United States.
Birth of the Moon • First Stage • Moon originally was once part of the Earth. • Scientists believe a very large body hit the Earth early in its development, throwing a huge amount of debris into orbit. • Debris eventually was influence by Earth’s gravity and formed the moon we have today.
Second Stage • After forming a sphere, the surface of the moon was covered by molten rock. • Eventually, this mix of rock separated. • Third Stage • The outer surface of the moon cooled, forming a crust. • Craters started to form from the constant bombardment by meteoroids. • Meteoroids decreased • Moon cooled completely • Moon changed little in 3 billion years
The Moon’s Surface • No atmosphere • No liquid water • Extreme temperatures • Daytime = 130C (265°F) • Nighttime = -190C (-310 F) • 1/6 Earth’s gravity
The Moon’s Surface • Features on the moon’s surface include maria, craters, and highlands.
Highlands • Mountains up to 7500 m (25,000 ft) tall • Light colored features
Craters • Bowl shaped depressions • Up to 2500 km (1,553 miles) across • Most formed by meteorite impact on the Moon • Some formed by volcanic action inside the Moon
Maria • Originally thought to be “seas” by early astronomers • Darkest parts of moon • Hardened rock formed from huge lava flows 3-4 billion years ago
Craters Maria
Movements of the Moon • Orbit is an ellipse, not circular • Revolution – Moon orbits the Earth every 27 1/3 days • Same side of Moon always faces Earth
Far Side of the Moon • First seen by Luna 3 Russian space probe in 1959 • Surface features different from near side • More craters • Very few maria • Thicker crust
It’s Just a Phase • Moonlight is reflected sunlight • Half the moon’s surface is always reflecting light • From Earth we see different amounts of the Moon’s lit surface • The amount seen is called a “phase”
Waxing and Waning • New moon • Waxing Crescent moon • First Quarter moon • Waxing Gibbous moon • Full moon • Waning Gibbous moon • Third Quarter moon • Waning Crescent moon • New moon
FOUR MAIN SHAPES FULL CRESCENT Four Basic Shapes GIBBOUS QUARTER
Lunar Eclipses • Moon moves into Earth’s shadow – this shadow darkens the Moon • About 2-3 per year • Last up to 4 hours • Only during full moon
Lunar Eclipse • During a lunar eclipse, Earth blocks sunlight fromreaching the moon’s surface.
Solar Eclipses • New Moon moves between Earth and Sun • Moon casts a shadow on part of the Earth • Total eclipses rare – only once every 360 years from one location!
Solar Eclipse • A solar eclipse occurs when the moon passes directly between Earth and the sun, blocking sunlight from Earth.
Annular Solar Eclipse May 20, 2012 • http://youtu.be/w806rVCEh50
Exploring the Moon • 1950s to 1960s - probes • Neil Armstrong First man on the Moon – July 20, 1969 • Six Apollo missions (1969-1972) • 12 Americans have walked on the moon • Possibly send people to moon again in 2018
Extra Credit for Astronomy Test: • Go to the website nasa.gov • Find a topic that you are interested in and print out the information. Write a ½ page summary of the information that you find, and ½ page of why you find this topic interesting and what other questions do you have regarding the topic. • 5 points • Due Wednesday