The Moon is the Earth’s only natural satellite. Like the Earth it is almost spherical..
It is approx 3,500 km in diameter, the fifth largest moon in the Solar System. The Earth is approx. 12,750 km in diameter.
The Moon orbits the Earth every 27.3 days. During each orbit it shows a series of phases: New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Waning Crescent, New Moon. We are observing at First Quarter.
At MoOnday the Moon is 387,106 km away from Earth. This distance does vary during its orbit. Why?
The Moon rotates on its axis at the same time it takes to orbit the Earth. This means that from Earth we only ever see approximately half of its surface but because of its wobble as it spins approximately 3/5th of the total surface has been observed from Earth.
The side that we see from Earth is called the near side while the other side is called the far side (it is sometimes called the dark side despite the fact that it illuminated by the Sun just as much as the near side).
The Moon is very hot during the day but very cold at night. The average surface temperature of the Moon is 107℃ during the lunar day and -153℃ at night.
The Earth’s tides are largely caused by the gravitational pull of the Moon. The effect of gravity is only about one fifth (17%) as strong on the surface of the Moon compared to the force of gravity on the surface of the Earth.
The Moon formed approx 4,500 million years ago when it is believed a Mars-size object struck the Earth spewing parts of our young planet into space. The Moon formed from this debris.
The Soviet Union’s Luna space programme featured the first successful landing of an unmanned spacecraft on the surface of the Moon in 1966.
The USA’s NASA hApollo 11 mission was the first manned Moon landing. The first person to set foot on the Moon was Neil Armstrong on 20 July 1969. At MoOnday you may observe several sites where Apollo missions landed on the Moon.
The light from the Sun reflects off the Moon’s surface into our eyes. We can see the Moon at times during the day (on MoOnday!). Reflections are how we see most things about us. Sunlight also reflects off planets and that is how we see them. Stars, like our Sun, are the sources of light.
When you gaze at the Moon without using a telescope or binoculars you can see dark patches and light areas. The dark patches are lava filled large plains called maria (latin for ‘seas’) formed by ancient volcanic eruptions. The light areas are mountain highlands.
When you look through a telescope or binoculars you can see a large number of craters of different sizes caused by the impact of asteroids and comets over time. Because there is no atmosphere on the Moon the craters do not weathered and retain their appearance.
Be sure to observe the maria, craters and where on the Moon humans first walked on the surface. Enjoy the meeting! Enjoy being a lunatic!