Our Moon & Moon Exploration

Our Moon & Moon Exploration Astronomy 1

Vocabulary • New moon • Waxing phase • Full Moon • Waning phase • Solar eclipse • Lunar eclipse • Tides • Craters • Marias • Highlands

Moon Facts • There is no air, liquid water or atmosphere • Temperatures range from 100°C to -170°C • There is little gravity compared to the Earth • 3,476 km in diameter (little less than the distance across the United States)

Origin of the Moon • Before the first manned explorations of the moon there were several theories on the origin of the moon • 1st: the moon was another smaller plane that was captured by Earth’s gravity • 2nd: the moon was created by loose, left over material from when the Earth was forming • 3rd: the moon was created by molten (liquid rock) material ejected from the Earth when the Earth was forming

Origin of the Moon • After the first mission scientists gather data that led them to create the Impact Theory • The Impact Theory is just as it sounds – in the early development of the solar system there were a lot of collisions and explosions between all the debris • It is believed that at one time the Earth was much larger than it is now and was hit by a Mars-sized planet, causing a chunk to break off, creating the moon

Origin of the Moon • Over time both the Earth and the moon were smoothed out to create the spheres we see today • They developed this theory because the lunar rocks that were gathered on the Apollo missions were no different than rocks you can find in the parking lot • Many of the hits the moon took as it formed can still be seen today – why?

Motions of the Moon • The moon would be considered a satellite because it revolves around the Earth • It takes approximately 27.3 days to make a complete trip around the Earth • The moon takes approximately 27.3 days to rotate on its axis • What does this mean? • This also means that we only see one side of the moon

Phases of the Moon • The moon it self does not give off any light – the only reason that we see the moon is because the light from the sun is reflecting off it • The different shapes of the moon you see at night are because the moon goes through phases as it revolves around the Earth and the sun is hitting it at different angles

Phases of the Moon • What causes the phases? The change in position of the moon relative to the sun and Earth is what causes the phases. • As the moon travels around the Earth, the sun hits different angles of the moon • For example, if the moon is angled towards Earth so only half is showing, then the sun will only hit the half we see

Phases of the Moon • New moon: the lighted sided of the moon is facing the sun, not Earth, and as a result the moon cannot be seen from Earth • Waxing phase: occurs after the new moon; the moon slowly begins to reappear in the sky, until it reaches a full moon • The Waxing Crescent is when only a sliver of the moon is visible – occurs just after the new moon • When one half of the moon is lit (1/4 of the total moon surface), the phase is called First Quarter • When more than one half of the moon is lit (1/2 of the total moon surface), the phase is called Waxing Gibbous

Phases of the Moon • Full Moon: the entire moon is lit by the sun • Waning Phase: occurs after the full moon; slowly begins to disappear in the sky, until it reaches the New Moon • When more than one half (1/2 of the surface) of the moon is showing, it is called the Waning Gibbous • When one half (1/4 of surface) of the moon is showing, it is called the Third Quarter • The Waning Crescent is when only a sliver of the moon is showing – just before the new moon

Eclipses • When the moon’s shadow hits the Earth or the Earth’s shadow hits the moon an eclipse occurs • There are two types: a lunar and a solar • During a New Moon the moon is directly between the Earth and the sun – this occurs approximately once a month

Eclipses • Solar eclipses are much more rare because only a few occur in a person’s lifetime • A solar eclipse occurs when the moon passes directly between the sun and the Earth – as a result you see a dark spot on the sun and the sky darkens until the moon, sun and Earth are no longer aligned

Eclipses • Lunar eclipses are still rare, but not as rare as a solar eclipse • A lunar eclipse occurs when the Earth passes between the sun and the moon – as a result the full moon will disappear in the sky until the moon, sun and Earth are no longer aligned

Tides • Tides in the ocean occur because of the attraction of gravity between the Earth and moon • Like the Earth revolving around the sun in a elliptical shape, the moon revolves around the Earth in an elliptical shape • High tides occur when the moon and Earth are closer together and the attraction is stronger • Low tide occurs when the moon and Earth and farther apart and the gravitational force is weaker

Studying the Moon • At the present time there are no missions planned to return to the moon • However, there is a spacecraft that was placed in the lunar orbit to study the moon • This craft is called Clementine • Many pictures of the moon’s surface have been compiled, now the space craft is used to track cold objects that move through space (e.g. satellites, asteroids, war-heads, etc.)

Studying the Moon • Clementine has given scientists almost a complete map of the moon’s surface • A depression has been discovered that is almost 12km deep and 2500km wide – the largest in the solar system • There is also a large plateau that is almost always facing the sun

Studying the Moon • Features used to describe the moon include: craters, highlands and Marias • Craters found depressions formed from high-speed meteoroids • These are evidence that the moon is geologically dead • Dark, flat areas are called Marias – formed by ancient lava flows • Highlands light-colored areas surrounding the maria

Craters Maria

Exploring the Moon • 1950s to 1960s - probes • 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

Missions to the Moon • Between 1964-1972 over a dozen missions to the moon occurred – both manned and unmanned • Apollo 11 was the first manned mission that actually landed on the moon safely • From this mission we got the quote “One small step for man, one giant leap for man-kind.”

Missions to the Moon • In later trips to the moon astronauts were able to stay for days instead of hours, and even had a lunar buggy so they could travel around the moon’s surface • Astronauts also discovered much about the inside of the moon • They found that there are no plates, like on Earth, so the surface does not shift • The core of the moon has cooled almost completely, unlike the core of the Earth so the moon is geologically dead

Ice on the Moon? Ice on the Moon? • 1994 – Clementine probe • 1998 – Lunar Prospector

Our Moon & Moon Exploration