The Moon: Earth s Closest Neighbor 238,866 miles away
The same age as Earth. It is believed that the moon is 4.5 billion years old.
Moon s Formation One theory The Capture Theory The moon formed elsewhere in the solar system and was captured by the Earth s gravity as it passed close to our planet
Moon s Formation Another theory The Colliding Planetesimals Theory Debris orbiting the Earth that was left over from the formation of the planet eventually came together to form the Moon
Moon s Formation Latest theory gaining popularity The Ejected Ring Theory A large object, perhaps as large as the planet Mars, struck the Earth and sent a large amount of the Earth s crust into space. The material eventually cooled and formed the Moon. Rock samples collected from moon supports this theory Show Moon and Earth s crust both contain small amounts of iron
Moon s Composition Volcanic eruptions on Moon formed volcanic rocks early in Moon s history, between 4 and 2.5 billion years ago Astronauts collected the rocks, brought them back to Earth, and were compared to Earth s volcanic rocks concluded rocks were similar Eruptions also created large plains of basalt lava called mares Since then there has not been any volcanic eruptions that we know of
Moon s Composition Surface of Moon is covered in impact craters Bowl-like remains of celestial objects such as asteroids that collided with the Moon The date of the craters suggests they were formed more than 4 million years ago Number of impacts has declined ever since
The Moon s Surface Covered with fine volcanic dust Formed by impact craters Does not have an atmosphere Gravity is 17% of Earth s gravity Temperature varies greatly during the day Noon temperature=200 F (93 C) Night temperature=-250 F (- 157 C)
The Moon s Surface Diameter=approximately 2,160 miles (3,475 km) 27% of Earth s diameter Explorations have recently revealed there might be frozen water near Moon s polar regions
The Moon s Orbit One orbit around Earth takes 27 days and 7 hours The same side of the Moon always faces the Earth The other side is always illuminated by the Sun Causes moon s different phases Orbit is elliptical-distance from Earth changes Perigee=closest to Earth Apogee=farthest from Earth
Phases of the Moon Different phases of the Moon occur at different points in its revolution around Earth Phases of the Moon is also known as lunar month 29 days and 12 hours long
Phases of the Moon New Moon Dark side of the Moon is facing Earth Moon appears as dark disk in the sky because no sunlight is striking the Moon s surface
Phases of the Moon Waxing Crescent Occurs approximately 3 days after the New Moon Moon s surface is lit in a crescent shape Moon has completed one-eighth of its orbit around Earth
Phases of the Moon First Quarter Moon, also known as Half Moon Occurs approximately 7 days into lunar cycle Moon s surface as viewed from Earth is half lit by sunlight
Phases of the Moon Waxing Gibbous Occurs approximately 9 days into lunar cycle Three-quarters of Moon s surface as viewed from Earth is lit by sunlight
Full Moon Phases of the Moon Occurs approximately 14 days into the lunar cycle Marks the approximate halfway point of the Moon s orbit around Earth The side of the Moon facing Earth is completely lit up by the Sun
Waning Gibbous Phases of the Moon Occurs approximately 17 days into the lunar cycle Three-quarters of Moon s surface is lit by the Sun, as viewed from Earth
Third Quarter Moon Phases of the Moon Occurs approximately 20 days into the lunar cycle Moon s surface facing Earth is once again half bathed in sunlight, causing another Half Moon Moon has completed 75% of its orbit around Earth
Phases of the Moon Waning Crescent Occurs approximately 23 days into the lunar cycle One-quarter of the Moon s surface, as viewed from Earth, is lit by the Sun
Phases of the Moon One lunar month is complete with the arrival of another New Moon Occurs when the Moon has made one full lunar cycle 29.5 days
Eclipses
Eclipses Occurs when either the Moon or the Earth is shadowed from the Sun by the other Caused by the Moon orbiting Earth Two types: Lunar Eclipse Solar Eclipse Dangerous to look directly at the Sun during any eclipse event
Lunar Eclipse Occurs when the Moon is shadowed from the Sun by Earth Only occurs during the Full Moon phase Can be a partial or total eclipse
Solar Eclipse Occurs when the Moon passes in front of the Sun Result of the Sun and Moon being the same apparent size in the sky Total solar eclipse causes the daytime sky to darken for a short time and allows for the unique view of the solar corona Sun s extremely hot outer atmosphere
Tides
Tides Bulges that are created on the Earth s surface by the gravitational attraction of the Moon and Sun Moon s influence is greater because it is closer Create a rise in sea level near the coastlines
Tides Geography of the coastline also influences tides Diurnal tides-locations experience one high tide and one low tide each day Common in the Caribbean Semi diurnal-two high tides and two low tides each day Northeastern United States
Spring tides Tides Occur during the time of the year when the Sun and Moon are on the same side, or on opposite sides of Earth Creates the highest and lowest tides of the year Neap tides Occurs during the time of the year when the Sun and Moon are at right angles to one another relative to Earth