# Part-1 Basic astronomy knowledge series. Learn about Moon here.

Updated on January 20, 2014

## Origin of the Moon

It is interesting to know that how the Moon was formed? What are the logic and theories behind it.

There are various theories but most known five major theories are:

A) The Fission Theory : The concept of this theory based on once the Moon was part of earth and separated from the earth.

B) The Capture Theory: The concept of this theory says the Moon was formed somewhere else in solar system and later captured by earth' s gravitational field.

C) The Co-accretion Theory: The concept of this theory based on that the Earth and Moon may have formed together at the same time from nebula by co-accretion.

D) The Colliding Planetesimal Theory: The concept of this theory based on that the Moon condensed from Earth;s orbiting and Sun's orbiting planetesimals.

E) Giant Impact Theory: This is most important and latest theory, which is remains to be discuss and widely accepted today. This theory proposes that during formation of solar system, a planetesimal (small planets) struck the Earth which causes ejecting large volume of heated materials from the outer layer of both and these materials joined together and formed Moon in orbit of earth.

## Basics about Moon !!!

Before going into further discussion Moon , It is very important to know basic about to the Moon. Read here and do not forget to attend the quiz test.

(1) The Moon is the only the Earth's satellite.

(2) The Moon revolves around the Earth in about 27 days 8 hours and also it rotates around its own axis. It is in synchronous rotation with Earth.

(3) Distance between Moon and Earth is around 3,84,000 KM ( average).

(4) At its closest approach (Perigee), the distance of Moon is 3,56,410 KM from Earth.

(5) At its farthest approach (Apogee), the distance of Moon is 4,06,700 KM from Earth.

## Facts about Moon !!!!

(1) The Moon's mass is 7.35 x 10 22 kg, which is 1/81 of the Earth's mass.

(2) The Moon's gravitational force is only 17% of the Earth's gravitational force.

(3) Temperature at moon ranges from 265 degree F to -170 degree F.

(4) The Moon has no atmosphere.

(5) The Moon's surface has craters, dry dusty and rocky surface.

## Basic parameters of the Earth and the Moon

Parameters
Moon
Earth
Mass
5.9736 x 10^24 kg
7.349 x 10^22 kg
Volume
1.08321 x 10 ^12 km^3
2.199 x 10^10 km^3
Equatorial radius (km)
1738.1
6378.1
Mean Diameter
12,742 km
3,476 km
Surface gravity
9.78 m/s^2
1.62 m/s^2

## Mission to the Moon

First successful landing on the Moon was Apollo 11's LEM ( Lunar Excursion Module). It was landed on the Moon on 20th July 1969 with Neil Armstrong and Edwin Buzz Aldrin. Neil Armstrong was the first man who set foot on Moon.

There are lots of orbiter and landing mission on Moon.There is also an Indian Moon Orbiter Mission Launched by Indian space agency ISRO called " Chandrayaan".

Recent lunar mission indicates that there might be some frozen ice at the poles.

## Indian Moon Mission " Chandrayaan"

Indian Space Research Organisation (ISRO) has successfully launched India's first moon mission "Chandrayaan" during 2007. It upgrades India's technological capabilities to launch further inter planetary mission in future. The objectives behind launch of "Chandrayaan" was to understand the Moon's origin, surface exploration and scientific experiments.

Chandrayaan was launched by PSLV (Polar Satellite Launching Vehicle ). Chandrayaan was the result of work behind National Lunar Mission Task Force (NLMTF), which was constituted by ISRO with India's leading scientist

Scientific payload on Chandrayaan were:

• Terrain Mapping Camera-TMC
• Hyper Spectral Imager-HySI
• Lunar Laser ranging Instrument-LLRI
• Low Energy X-ray Spectrometer-LEX
• Solar X-ray Monitor- SXM
• High Energy X-ray /g-ray
• Spectrometer-HEX

.

## Test your knowledge with 5 question here...

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