The MoonThe Moon

Earth’s natural satelliteEarth’s natural satellite

Basic FactsBasic Facts

• The Moon orbits the Earth at a distance The Moon orbits the Earth at a distance of approximately 380 000kmof approximately 380 000km

• Its diameter is a quarter of Earth’s, while Its diameter is a quarter of Earth’s, while its mass is eighty times less than Earth’sits mass is eighty times less than Earth’s

• This means that it’s gravity is 1/6 that of This means that it’s gravity is 1/6 that of the Earththe Earth

• So a man who weighs 100N on Earth So a man who weighs 100N on Earth would have a weight of 16.67N on the would have a weight of 16.67N on the MoonMoon

• The Moon has no atmosphere and this The Moon has no atmosphere and this means it has no protection against means it has no protection against meteorite strikes, thus it is covered by meteorite strikes, thus it is covered by many cratersmany craters

One giant leapOne giant leap…• The Moon is the only object The Moon is the only object

in the Solar System that in the Solar System that humans have walked on humans have walked on (other than Earth obviously!)(other than Earth obviously!)

• In 1969 Neil Armstrong In 1969 Neil Armstrong became the first man to walk became the first man to walk on the Moonon the Moon

The phases of the MoonThe phases of the Moon

• The Moon orbits the Earth approximately once The Moon orbits the Earth approximately once every 28 daysevery 28 days

• At the same time it spins on its axis. This means At the same time it spins on its axis. This means that only one side of the Moon faces the Earth.that only one side of the Moon faces the Earth.

• As the Moon orbits the Earth, a larger area of As the Moon orbits the Earth, a larger area of the nearside becomes illuminated by the Sunthe nearside becomes illuminated by the Sun

• It is this that causes the phases of the MoonIt is this that causes the phases of the Moon

The phases of the The phases of the Moon (2)Moon (2)

SUNLIGHT

3. Further round and a waxing half moon is formed

5. Fourteen days after the New Moon, and now all sunlight is falling on the nearside of the Moon– a Full Moon

4. Waxing gibbous Moon

6. Waning gibbous

7. Waning half moon

8. Waning crescent

1.New Moon – All sunlight falls on farside of Moon facing away

from the Earth.

2. As Moon orbits around Earth a waxing crescent forms

Shows portion of Moon visible to an observer on the Earth

Inner circle = Position of Moon in its orbit around Earth

Outer circle = What Moon looks like from Earth

EclipsesEclipses• An eclipse occurs when light from a body An eclipse occurs when light from a body

in space is blocked by another objectin space is blocked by another object

• Eclipses can either be Eclipses can either be solarsolar or or lunarlunar

• In a solar eclipse the Sun is obscured by In a solar eclipse the Sun is obscured by the Moonthe Moon

• In a lunar eclipse the Moon is obscured by In a lunar eclipse the Moon is obscured by the Earth itselfthe Earth itself

Partial eclipsePartial eclipse

Total eclipseTotal eclipse

Solar EclipseSolar Eclipse

SUNSUN MOONMOON EARTHEARTH

In a solar eclipse the Moon passes between the Earth and the Sun. The In a solar eclipse the Moon passes between the Earth and the Sun. The Moon casts a shadow on the Earth’s surface. The shadow consists of Moon casts a shadow on the Earth’s surface. The shadow consists of two areas: the two areas: the umbraumbra where a total eclipse can be seen; and the where a total eclipse can be seen; and the penumbrapenumbra an area where a partial eclipse can be observed. an area where a partial eclipse can be observed.

NOT TO SCALE!

Lunar EclipseLunar Eclipse

SUNSUN MOONMOONEARTHEARTH

In a lunar eclipse, the Earth is between the Sun and the Moon. In a lunar eclipse, the Earth is between the Sun and the Moon. The Earth casts a shadow, blocking out light that can reach the The Earth casts a shadow, blocking out light that can reach the Moon. The Moon often goes a deep red colour, as opposed to Moon. The Moon often goes a deep red colour, as opposed to being obscured completely – this is because red light is refracted being obscured completely – this is because red light is refracted by the Earth’s atmosphere.by the Earth’s atmosphere.

NOT TO SCALE!