The Moon


The Moon is Earth’s nearest natural satellite. It is the fifth largest moon in our Solar System. Our Moon is bigger than Planet Pluto. It is the only object in the solar system atmavisited by humans.

Moon Picture

Moon Facts

The moon is about one quarter the size of Earth and it has about one-sixth of the Earth’s gravity. It has a black sky, has almost no atmosphere due to its weak gravity. Without an atmosphere, there is no wind, no clouds and no rain.

* Distance: Mean distance from Earth to the Moon is 384,000km (238,900 miles)

* Diameter: 3,476km (2,160 miles)

* Mass: 7.35 X 1022 kg. This about one-eightieth of the Earth’s mass.

* Moon’s rotation: Rotates about its own axis in 27 days and 8 hours, which is about the same time it takes to orbit the earth. Hence the same face of the moon is always facing the Earth. The far side always faces away and cannot be seen from Earth. It has been photographed by spacecraft.

* Escape velocity: 2.38 km/sec

* Moon Surface: It is covered with craters, lava plains, mountains and valleys. No active volcanos.

* Temperature: Ranges from -171?C to 111?C.

* Mass: 0.012 (Earth = 1)


The Moon is about 4 and a 1/2 billion years old.


The craters on the surface were made when meteorites (space rock) hit the moon. South Pole-Aitken basin is the largest basin on the moon and is about 2500 km (1553 miles) across and more than 8 km (5 miles) deep.


People call it ‘the Moon’ because until Galileo Galilei discovered 4 moons around Planet  Jupiter in 1610, they didn’t know other moons existed.

In different languages it has different names. In latin its called Luna. In Greek its called Selene. Selene is the goddess of the moon.


The moon rotates at the same rate as it revolves around Earth.


The moon is less than a third the width of Earth.


It can be seen clearly with your eyes. For better viewing you can use binoculars, or a telescope. Galileo in 1609 was the first to look at it through a telescope.


Water was discovered on the moon by Indian lunar mission Chandrayaan-1 in November 2009.

Phasing of our Moon

Our Moon goes through phases during the lunar month. The lunar month is the 29.53 days it takes to go from one new moon to the next. The moon phase is the shape you see which follows the same pattern every four weeks.

The shape of the moon appears to change due to the different amounts of light being reflected on it and is caused by the relative positions of the Earth, moon, and sun. At full Moon and new Moon, the Sun, Earth and Moon are lined up.


Day 0 – New Moon is when no light is reflected so the moon appears dark because it is between our sun and the Earth and the brightness of our sun outshines the Moon.

Day 4 – Waxing Crescent is when there is a little bit of light on the moon and its illuminated surface appears to grow (wax) to full.

Day 7 – First Quarter Moon is when half of the Moon’s surface is illuminated and looks like half-circle. It is is one-quarter of the way through the lunar month.

Day 10 – Waxing Gibbous is when the moon is nearly, but not full.

Day 14 – Full Moon is when it is farther away from the sun than the earth and appears as a bright, round disk.

Day 18 – Wanning Gibbous is when it wanes (grows thinner/decreases each night).

Day 22 – Last Quarter is when the moon appears as a half-circle again. The dark side in the first quarter phase is now the lit side.

Day 26 – Waning Crescent

Day 29 – New Moon is repeated each lunar month and is the start of new cycle.


The Moon has only been walked on by 12 astronauts during the Apollo program in the late 1960s and early 1970s. They were all male. No women have walked on the Moon.

Exploration Highlights:

– First photograph of the far side of the Moon was by Soviet Luna 3 spacecraft in October 1959.
– First soft landing on the Moon was by Soviet Luna 9, launched on 31st January 1966 and landed on 3rd February 1966.
– First unmanned spacecraft to orbit the Moon was Luna 10. It was also the first artificial satellite of the Moon.
– First manned flight around the moon was Apollo 8 in December 1968. It was also the first crewed flight to orbit the moon and return to Earth.
– First manned landing and walk was during the Apollo 11 mission on July 20th 1969. The first man to walk on the moon was Neil Armstrong on the Apollo Mission in 1969.
– First robotic space probe to land on the Moon and return a sample of soil to Earth was Lunar 16 in 1970.
– The last man on the moon was Eugene Cernan in Apollo 17 on December 1972.
– Last Soviet / Russian mission to the Moon was Luna 24 in 1976.
– Smart-1 was the first European Lunar Spacecraft. It was launched in 2003.


SpaceX plans to send 2 tourists around Moon using a crewed Dragon Spacecraft in 2018 (cancelled).

First Crewed Landings of our Moon in 21st Century planned are:
Japan (2030)
Russia (2030)
USA (2030)

First Woman to walk on the Moon hopefully in 2030s or earlier (lets hope).

Did you know?

* The main cause of the rise and fall of ocean tides is the moon’s gravitational pull on the Earth.

* Regolith is the soil that covers the Moon and is composed of rock fragments and fine dust grains. The big dark spots of wide flat areas of rock are called seas or maria.

* Is the moon made of cheese? No cheese has ever been found on the moon.

* There is no such thing as the “dark side of the moon”. The sun shines on all sides.

Click on the links to learn more about the moon landing and other luna spacecraft.

Robotic Moon Spacecraft:

List of Moon Missions:
Lunokhod: First Moon Rover – Updated
Clementine: USA
Selene: Japan
Luna Prospector: USA

Manned Moon Missions:

Project Apollo: US Moon Landing Missions
Zond L-1: Circum-Lunar Spacecraft of the 1960’s and early 70’s. The Project was initiated, but Aborted.
N-1 Story: Soviet’s Manned Moon Program

Moon Links:

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