Moon, Moon Phases & Eclipses

The Moon

Myths about the Moon The Moon is made of cheese! There is a Man in the Moon. The Moon and the Sun chase each other across the sky. The Moon disappears during certain days of the month. There are men or other creatures living on the Moon. The Moon was put in the sky by a person or animal. The Moon is a living creature or a god. The Moon controls how we act and how we feel. During a full moon, some people turn into werewolves. The Moon is pulled across the sky by a person, animal, or force.

Myths Greek goddess Artemis, roman goddess Diana

Myths Chinese mythology: Chang’e Moon festival

Calendar The current standard calendar is solar calendar (Gregorian calendar) – counting days The moon phases have a period of 29.5 days, a good measure of time Lunar calendars – counting days and months E.g. Islamic calendar is a lunar calendar 29.5 * 12 = 354, 11 days less than 365 Lunisolar calendar – Chinese calendar, Hebrew calendar Adding leap months, with a circle of 19 years

Moon – our closest natural celestial body neighbor The earth’s only natural satellite Orbit around the earth is an eclipse Average distance from the earth to the moon is 384,403 kilometers (238,857 miles) – 30 times the diameter of the earth Diameter of 3,474 km, ¼ of the earth Gravity 1/6 of the earth

Moon’s orbit The orbit period around the earth – 27.3 days The spin period is exactly the same! We always see the same side of the moon! ( precisely speaking 59% of the surface during the whole period of the moon revolution. Reason: libration) The period of Lunar Phase – 29.5 days Because of the earth’s revolution in the space The orbit plane of the moon is tilted by ~5 degree with respect to the earth’s orbit around the sun, unlike other planets

Moon’s orbit The orbit plane of the moon is tilted by ~5 degree with respect to the earth’s orbit around the sun, unlike other planets

Near Side Far Side

Moon’s surface Maria (sigular mare, ‘sea’ in Latin) –Dark areas and were thought to be seas –Cover 31% of the near side, but only 2% of the far side –No water but vast pools of solidified lava that flowed into basins formed by comets/metors colliding –Nomenclature Latin terms describing the weather and abstract concepts –Smaller dark regions Lacus (Lake) Palus (marsh) Sinus" (bay) Maria Highland Crater

Moon’s surface Highland –Lighter color regions, or called Terrae –Many are impact basins’ outer rims –In contrast to earth, no major lunar mountains were formed as a result of tectonic events –Mountains and mountain ranges –Different brightness of the highlands and maria is because they are composed of different rock types Maria Highland Crater

Craters Formed when asteroids/comets hit the lunar surface Half a million craters with diameters larger than 1km Crater counting – to estimate the age of the lunar surface The largest crater is South Pole-Aitken basin, with 2,240 kms in diameter and 13 kms in depthSouth Pole-Aitken basin Nomenclature: –Large craters, deceased famous scientists, artists –Small craters, common first names Daedalus, 93 km in diameter Proposed as a site for a large radio telescope

Known maria, highlads and craters

The formation of the moon Born from the earth - broke off from the earth by centrifugal forces, and left the pacific ocean behind Captured by the earth’s gravity Co-formation with the earth Giant impact hypothesis –An impact of a Mars-sized body collide w/ the proto- Earth and ejected materials to orbit around the earth – the Moon

Explorations of the moon Ancient people observed the moon by naked eyes, and wrote poems and essays, and told myths Galileo first observed the moon using an telescope The only celestial body the human being has orbited and landed –First impact: Luna 2 of Soviet Union in 1959 –First far side picture: Luna 3 in 1959 –First soft landing: Luna 9 in 1966 –First men’s step on the moon: Apollo 11 in 1969

Moon Phases Why does the moon change phases? Lunar phases are the result of our eyes seeing the illuminated half of the Moon from different viewing geometries Due to the Moon’s orbital positions

The Moon’s Orbit around the earth

Moon Phases

Complete this Moon PhaseMoon Rise Time New MoonSunrise/6am Waxing Crescent9am First Quarter12pm Waxing Gibbous3pm Full Moon6pm Waning Gibbous9pm Third Quarter12am Waning Crescent3am Say, Sun rises at 6am and sets at 6pm

When new moon occurs, what is the phase of the earth if you stand on the moon? Full earth! The earth always has an opposite phase to the moon.

Eclipses Have you seen eclipses? What are eclipses in nature? –One celestial object casts its shadow on the other one

Solar Eclipses Sun – the shadow of the moon on the earth Total solar eclipse in 1999

A – total eclipse B – annular eclipse C – partial eclipse

Lunar Eclipses Moon – the shadow of the earth on the moon

Lunar Eclipse

What’s the moon phase when a solar eclipse occurs? What’s the moon phase when a lunar eclipse occurs? New Moon Full Moon

Why aren’t there solar eclipses and lunar eclipses on EVERY new moon and full moon?

Two conditions must be satisfied for an eclipse to occur 1.The nodes of the moon’s orbit must be nearly aligned with the Sun and the Earth 2.The phase of the moon must be new or full

Eclipses Cycle Every year there are at least two lunar eclipses Lunar eclipses and solar eclipses always come in pairs Lunar eclipses can be seen everywhere on the earth, but the solar eclipses may only be seen on part of the earth

Discussion Board Research and Describe perigee and apogee. Blue Moon

Solar eclipses