Monday, December 12, 2016

Facts about The Moon

A moon is defined to be a celestial body that makes an orbit around a planet, including the eight major planets, dwarf planets, and minor planets. A moon may also be referred to as a natural satellite, although to differentiate it from other astronomical bodies orbiting another body, e.g. a planet orbiting a star, the term moon is used exclusively to make a reference to a planet’s natural satellite.

The Moon is the Earth’s only natural satellite. A natural satellite is a space body that orbits a planet, a planet like object or an asteroid.

The Moon

It is the fifth largest moon in the Solar System. Learn more about the other moons in the Solar System.

The average distance from the Moon to the Earth is 384403 kilometres (238857 miles).

The Moon orbits the Earth every 27.3 days.

Mons Huygens is the tallest mountain on the Moon, it is 4700 metres tall, just over half the height of Mt Everest (8848m).

The Moon rotates on its axis in around the same length of time it takes to orbit the Earth. This means that from Earth we only ever see around 60% of its surface (50% at any one time).

The effect of gravity is only about one fifth (17%) as strong on the surface of the Moon compared to the strength of gravity on the surface of the Earth.

The Soviet Union’s Luna program featured the first successful landing of an unmanned spacecraft on the surface of the Moon in 1966.

The USA’s NASA Apollo 11 mission in 1969 was the first manned Moon landing.

The first person to set foot on the Moon was Neil Armstrong of the U.S.A.

The far side of the Moon looks quite different due to its lack of maria (ancient pools of solidified lava).

The surface of the Moon features a huge number of impact craters from comets and asteroids that have collided with the surface over time. Because the Moon lacks an atmosphere or weather these craters remain well preserved.

Although research is continuing, most scientists agree that the Moon features small amounts of water.

The Moon is very hot during the day but very cold at night. The average surface temperature of the Moon is 107 degrees Celsius during the day and -153 degrees Celsius at night.

The phases of the Moon are: New Moon, Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Last Quarter, Crescent, New Moon.

A lunar eclipse occurs when the Earth is between the Sun and the Moon.

The Beginning of a Lunar Eclipse

According to the leading theory, The Moon was created when a rock the size of Mars slammed into Earth, shortly after the solar system began forming about 4.5 billion years ago.

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 facing away from Earth has only been seen by the human eye from 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.

The Moon is drifting away from the Earth. It 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. That is because 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 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 and 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.

Neil Armstrong

Gene Cernin

Walking on the Moon

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.

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 Sueface of The Moon

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 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 the volume 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.

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.

During the 1950’s the USA considered detonating a nuclear bomb on the Moon. The secret project was during the height 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.

An interesting thing about the moon is that it always shows us the same face. That is because
long ago, the Earth's gravitational effects slowed the moon's rotation about its axis. Once the moon's rotation slowed enough to match its orbital period (the time it takes the moon to go around Earth) the effect stabilized. Many of the Moons around other planets behave similarly.

What about phases? Here's how they work: As the Moon orbits Earth, it spends part of its time between us and the Sun, and the lighted half faces away from us. This is called a new moon. So, there is no such thing as a "dark side of the Moon," just a side that we never see. As the moon swings around on its orbit, a thin sliver of reflected sunlight is seen on Earth as a crescent moon. Once The Moon is opposite the Sun, it becomes fully lit from our view. That is known as a full moon.

Phaases of the Moon

More than 400 trees on Earth came from the Moon's lunar orbit. In 1971, Apollo 14 astronaut Stuart Roosa took a bunch of seeds with him and, while Alan Shepard and Edgar Mitchell were busy sauntering around on the surface, Roosa guarded his seeds. Later, the seeds were germinated on Earth, planted at various sites around the country, and came to be called the Moon trees. Most of them are doing fine.

The Moon is not round (or spherical). Instead, it's shaped like an egg. If you go outside and look up, one of the small ends is pointing right at you. And the moon's center of mass is not at the geometric center of the satellite; it's about 1.2 miles (2 kilometers) off-center.

Apollo astronauts used seismometers during their visits to the Moon and discovered that the gray orb isn't a totally dead place, geologically speaking. Small moonquakes, originating several miles (kilometers) below the surface, are thought to be caused by the gravitational pull of Earth. Sometimes tiny fractures appear at the surface, and gas escapes.

Scientists say they think the Moon probably has a core that is hot and perhaps partially molten, as is Earth's core. But, data from NASA's Lunar Prospector spacecraft showed in 1999 that the moon's core is small, probably between 2 percent and 4 percent of its mass. This is tiny compared with Earth, in which the iron core makes up about 30 percent of the planet's mass.

 NASA's Lunar Prospector Spacecraft 

The Moon is bigger than Pluto. And at roughly one-fourth the diameter of Earth, some scientists think the moon is more like a planet. They refer to the Earth-moon system as a "double planet." Pluto and its Moon, Charon, are also called a double-planet system by some.



Tides on Earth are caused mostly by the moon The Sun has a smaller effect. Here's how it works: The Moon's gravity pulls on Earth's oceans. High tide aligns with The Moon as Earth spins underneath. Another high tide occurs on the opposite side of the planet because gravity pulls Earth toward the moon more than it pulls the water. At full Moon and new moon, the Sun, Earth and moon are lined up, producing the higher than normal tides (called spring tides, for the way they spring up). When the moon is at first or last quarter, smallerneap tides form. The Moon's 29.5-day orbit around Earth is not quite circular. When the moon is closest to Earth (called its perigee), spring tides are even higher, and they're called perigean spring tides. All this tugging has another interesting effect: Some of Earth's rotational energy is stolen by the moon, causing our planet to slow down by about 1.5 milliseconds every century.

As you read this, the Moon is moving away from us. Each year, the moon steals some of Earth's rotational energy, and uses it to propel itself about 3.8 centimeters higher in its orbit. Researchers say that when it formed, the moon was about 14,000 miles (22,530 kilometers) from Earth. It's now more than 280,000 miles, or 450,000 kilometers away.

A Red Moon Eclipse

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