Earth's Moon: Formation, Composition and Orbit

The moon is the easiest celestial object to find in the night sky — when it's there. Moon phases and the moon's orbit are a mystery to many. Because it takes 27.3 days both to rotate on its axis and to orbit Earth, the Moon always shows us the same face. We see the Moon because of reflected sunlight. How much of it we see depends on its position in relation to Earth and the Sun.
Though a satellite of Earth, the Moon is bigger than Pluto. Some scientists think of it as a planet (four other moons in our solar system are even bigger), though that viewpoint has never caught on officially. There are various theories about how the Moon was created, but recent evidence indicates it formed when a huge collision tore a chunk of the Earth away.


The moon is Earth's only natural satellite. The moon is a cold, dry orb whose surface is studded with craters and strewn with rocks and dust (called regolith). The moon has no atmosphere. Recent lunar missions indicate that there might be some frozen ice at the poles. 
The same side of the moon always faces the Earth. The far side of the moon was first observed by humans in 1959 when the unmanned Soviet Luna 3 mission orbited the moon and photographed it. Neil Armstrong and Buzz Aldrin (on NASA's Apollo 11 mission, which also included Michael Collins) were the first people to walk on the moon, on July 20, 1969. 

Physical characteristics of Earth's moon

1.Formation

The leading explanation for how the moon formed was that a giant impact knocked off the raw ingredients for the moon off the primitive molten Earth and into orbit. Scientists have suggested the impactor was roughly 10 percent the mass of Earth, about the size of Mars.

2.Internal structure

The moon very likely has a very small core just 1 to 2 percent of the moon's mass and roughly 420 miles (680 km) wide. It likely consists mostly of iron, but may also contain large amounts of sulfur and other elements.

3.Surface composition

Like the four inner planets, the moon is rocky. It's pockmarked with craters formed by asteroid impacts millions of years ago. Because there is no weather, the craters have not eroded.

4.

Atmosphere of the moon

The moon has a very thin atmosphere, so a layer of dust — or a footprint — can sit undisturbed for centuries. And without much of an atmosphere, heat is not held near the planet, so temperatures vary wildly. Daytime temperatures on the sunny side of the moon reach 273 degrees F; on the dark side it gets as cold as -243.

Moon Facts

There are many interesting facts about the moon and trivia that may or may not be important to you. Some interesting facts include:

• When Alan Sheppard was on the moon, he hit a golf ball and drove it 2,400 feet, nearly one half a mile.
  
• In a survey conducted in 1988, 13% of those surveyed believed that the moon is made of cheese.
  
• The multi layer space suits worn by the astronauts to the moon weighed 180 pounds on earth, but thirty pounds on the moon due to the lower gravity.
  
• How close can you get without completely running out of gas? Apollo 11 had only 20 seconds of fuel left when they landed on the moon.
  
• Apollo 15 was the first mission to use a lunar rover. The top speed that was ever recorded in this 4-wheeled land vehicle was 10.56 miles per hour.
  
• It is possible to have a month without a full moon. This occurs in February, but either January or March will have two moons.
  
• In China, the dark shadows that are on the moon are called "the toad in the moon".
  
• The Apollo missions brought back 2196 rock samples weighing 382 kg in total

Facts About the Moon

• The moon is not a planet, but a satellite of the Earth.
  
• The surface area of the moon is 14,658,000 square miles or 9.4 billion acres
  
• Only 59% of the moon's surface is visible from earth.
  
• The moon rotates at 10 miles per hour compared to the earth's rotation of 1000 miles per hour.
  
• When a month has two full moons, the second full moon is called a blue moon. Another definition of a blue moon is the third full moon in any season (quarter of year) containing 4 total full moons.
  
• From Earth, we always see the same side of the moon; the other side is always hidden.
  
• The dark spots we see on the moon that create the image of the man in the moon are actually craters filled with basalt, which is a very dense material.
  
• The moon is the only extraterrestrial body that has ever been visited by humans. It is also the only body that has had samples taken from it.
  
• The first space craft to send back pictures from the moon was Luna 3 (built by the Soviet Union) in October 1959.
  
• The moon has no global magnetic field.
  
• The moon's diameter is about 1/4 the diameter of the Earth. About 49 moons would fit inside the Earth.

What is a Super Full Moon?

The distance of the moon from the Earth varies throughout the month and year. The average distance is about 238,000 miles (382,900 kilometers). The moon's position furthest away from Earth is called “apogee” while its closest approach to Earth is referred to as “perigee”. These events do not regularly coincide with the phases of the moon. However, it can happen that the moon is at perigee during the phase of full moon. This event is referred to as Super Full Moon.

A super full moon occurs when the moon’s closest approach to the Earth (lunar perigee) coincides with the phase of full moon. When this happens the moon may seem bigger and brighter. However, for the ordinary star-gazer there will be no significant difference.

10 Need-to-Know Things About Earth's Moon:

1. If the sun were as tall as a typical front door, Earth would be the size of a nickel and the moon would the size of a green pea.
2. The moon is Earth's satellite and orbits the Earth at a distance of about 384 thousand km (239 thousand miles) or 0.00257 AU.

   Twelve human beings have walked on the moon.

3. The moon makes a complete orbit around Earth in 27 Earth days and rotates or spins at that same rate, or in that same amount of time. This causes the moon to keep the same side or face towards Earth during the course of its orbit.
4. The moon is a rocky, solid-surface body, with much of its surface cratered and pitted from impacts.
5. The moon has a very thin and tenuous (weak) atmosphere, called an exosphere.
6. The moon has no moons.
7. The moon has no rings.
8. More than 100 spacecraft been launched to explore the moon. It is the only celestial a body beyond Earth that has been visited by human beings (The Apollo Program).
9. The moon's weak atmosphere and its lack of liquid water cannot support life as we know it.
10. Surface features that create the face known as the "Man in the moon" are impact basins on the moon that are filled with dark basalt rocks.

shailesh kr shukla

directoratace@gmail.com