45 years ago on 16 July, Apollo 11 blasted off with a trajectory towards the Moon. Four days later, Neil Armstrong stepped out of the Apollo 11 lunar module, Eagle, and became the first man to set foot on our lunar surface. In celebration of this 20 July 1969 momentous event, I have extracted a few salient pieces of information on our Moon.
The dark side of the moon is a myth. In reality both sides of the Moon see the same amount of sunlight however only one face of the Moon is ever seen from Earth. This is because the Moon rotates around on its own axis in exactly the same time it takes to orbit the Earth, meaning the same side is always facing the Earth. The side we see is lit by reflected sunlight, while the side facing away from Earth lies in darkness and has only been seen by the human eye from a spacecraft.
The rise and fall of the tides on Earth is caused by the Moon. There are two bulges in the Earth due to the gravitational pull that the Moon exerts; one on the side facing the Moon, and the other on the opposite side that faces away from the Moon. The bulges move around the oceans as the Earth rotates, causing high and low tides around the globe. Did you know that the Moon is also pulling at the crust of the Earth causing it to bulge up? You actually move a few meters every time the Moon is overhead, but you just don’t notice.
The Moon is drifting away from the Earth. The Moon is moving approximately 3.8 cm away from our planet every year. It is estimated that it will continue to do so for around 50 billion years. By the time that happens, the Moon will be taking around 47 days to orbit the Earth instead of the current 27.3 days.
A person would weigh much less on the Moon. The Moon has much weaker gravity than Earth, due to its smaller mass, so you would weigh about one sixth (16.5%) of your weight on Earth. This is why the lunar astronauts could leap and bound so high in the air.
The Moon has no atmosphere. This means that the surface of the Moon is unprotected from cosmic rays, meteorites and solar winds, and has huge temperature variations. The lack of atmosphere means no sound can be heard on the Moon, and the sky always appears black. Its surface temperature is between minus 233 to 123 °C.
The Moon has quakes. These are caused by the gravitational pull of the Earth. Lunar astronauts used seismographs on their visits to the Moon, and found that small moonquakes occurred several kilometres beneath the surface, causing ruptures and cracks. Scientists think the Moon has a molten core, just like Earth.
The Moon is the fifth largest natural satellite in the Solar System. At 3,475 km in diameter, the Moon is much smaller than the major moons of Jupiter and Saturn. Earth is about 80 times larger than the Moon, but both are about the same age. A prevailing theory is that the Moon was once part of the Earth, and was formed from a chunk that broke away due to a huge object colliding with Earth when it was relatively young.
During the 1950’s the USA considered detonating a nuclear bomb on the Moon. The secret project was during the height of the cold war was known as “A Study of Lunar Research Flights” or “Project A119″ and meant as a show of strength at a time they were lagging behind in the space race.
The first spacecraft to reach the Moon was Luna 1 in 1959. This was a Soviet craft, which was launched from the USSR. It passed within 5995 km of the surface of the Moon before going into orbit around the Sun.
The Moon has only been walked on by 12 people; all American males. The first man to set foot on the Moon in 1969 was Neil Armstrong on the Apollo 11 mission, while the last man to walk on the Moon in 1972 was Gene Cernan on the Apollo 17 mission. Since then the Moon has only be visited by unmanned vehicles.
The Moon will be visited by man in the near future. NASA plans to return astronauts to the moon to set up a permanent space station. Mankind may once again walk on the moon in 2019, if all goes according to plan.