The Moon A look at our nearest neighbor in Space! Free powerpoints at http://www.worldofteaching.com
What is the Moon? • A natural satellite • One of more than 96 moons in our Solar System • The only moon of the planet Earth
Location, location, location! • About 384,000 km (240,000 miles) from Earth • 3,468 km (2,155 miles) in diameter (about ¼ the size of Earth)
Orbits (revolves around) Earth every 27.3 days Elliptical orbit (not a perfect circle) • About 384,000 km (240,000 miles) from Earth • 360,000 km 406,000 km • 224,000 miles 252,000 miles
Earth Plane of earth’s orbit Moon Plane of lunar orbit Moon
The Moon orbits the Earth at a 5o angle with respect to the Earth’s orbit around the Sun.
The Earth-Moon System • Apogee- point at which the Moon is farthest from Earth • Perigee- point at which the Moon is closest to Earth
Birth of the Moon • “Born” 4-5 billion years ago • Formed from impact of Mars-sized “planetesimal” on Earth • Debris from both objects melted together to form the Moon
Space Exploration • 1957- the Soviet Union launches, Sputnik, the first artificial satellite • 1958- the U.S. launched its first, Explorer 1 • Thousands now orbit the Earth
Exploring the Moon • Neil Armstrong First man on the Moon – July 20, 1969 • Six Apollo missions (1969-1972) • 382 kg (842 lbs) rocks • 12 Americans have walked on the moon
Movements of the Moon • Revolution: the Moon orbits the Earth every 27.3 days • Rotation – Moon turns on its axis every 27.3 days • We always see the same side of the Moon because its period of rotation equals its revolution! • This is called synchronous rotation.
Movements of the Moon • The moon rises in the east and sets in the west • The moon rises and sets 50 minutes later each day
Cut to the Core • 3 major divisions of the Lunar interior • Crust - average thickness of about 70 kilometers • Mantle • Core - radius is between 300 and 425 kilometers
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 Lunar Surface Highlands • Mountains up to 7500 m (25,000 ft) tall • Ridges- long, narrow elevations of rock that crisscross the moon’s surface. Highlands
The Lunar SurfaceMaria • Originally thought to be seas by early astronomers like Galileo and he named them for their “sea”-like appearance • Darkest areas made chiefly of basalt rock (igneous rock) • Filled by lava after crash of huge meteors on lunar surface • Formed 3-4 billion years Mare
Lunar FeaturesRilles Long, deep ancient lava channels (trench-like valleys) leftover from the formation of maria
Lunar FeaturesCraters • Most formed by meteor impact on the Moon • Some formed by volcanic action inside the Moon • Young craters characterized by bright streaks, called rays • Up to 2500 km (1,553 miles) across
Lunar FeaturesRegolith Fine layer of dust and rock that covers the moon’s surface
Lunar FeaturesRocks • Mostly made of Basalt (iron and magnesium rich volcanic rock) • Similar to igneous rocks found in Earth’s crust • Breccia- contain fragments of other rocks fused together
Limb The line where the surface of the moon meets the sky. Terminator The imaginary line between the reflected light and shadow.
Craters Can you see the rays? Maria Does this photo show us a limb or terminator line?
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”
Illumination of the Moon • Waxing- occurs when the size of the lighted part of the Moon is increasing • Waning- occurs when the size of the lighted part of the Moon is decreasing
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
Moon rise times: • The New Moon always rises at sunrise. • The first quarter Moon rises at noon. • The Full Moon rises at sunset. • The last quarter Moon rises at midnight. • Moonrise takes place about 50 minutes later each day than the day before.
Eclipses • Eclipses are caused when one celestial body passes through the shadow of another • The Sun and Moon occasionally line up with the Earth so that an eclipse occurs
Lunar Eclipses • Only occurs when a there’s a full moon • The Earth passes between the Sun and the Moon and the shadow of the Earth falls on the Moon and darkens it. • About 2-3 per year • Last up to 4 hours
Lunar Eclipses • Penumbra A portion of the light source is blocked and an observer in the penumbra experiences a partial lunar eclipse • Umbra The light source is completely blocked and an observer in the umbra experiences a total lunar eclipse
Lunar Eclipses Why is the moon red during a lunar eclipse?
Lunar Eclipses • Even during a total lunar eclipse, sunlight is bent around Earth through the atmosphere • The Moon is visible and appears to have a reddish tint
Lunar Eclipses Indirect sunlight still manages to reach and illuminate the moon. However, this sunlight must first pass deep through the Earth's atmosphere which filters out most of the blue colored light. The remaining light is a deep red or orange in color and is much dimmer than pure white sunlight.
Solar Eclipses • Only happens at new moon • Moon moves between Earth and Sun • Moon casts a shadow on part of the Earth • Total solar eclipses rare – only once every 360 years from one location!
The Tides • The Moon’s gravity tugs on the Earth. • It pulls the most on the part of Earth closest and least on the farthest causing tidal bulges • High tide – • Side facing Moon and side away from Moon • Low tide – • On sides of Earth Note: The earth rotates within the tidal bulge
Moon base of the future? • What would you need to live there?
Name this phase! Full Moon What time does this phase rise and set?
Name these features. Craters Maria Name these features.