Moon
Natural satellite of the Earth
- Moon is the only natural satellite of the earth.
- The study of moon is called Selenology
- Moon is also known as “fossil planet”.
- Classified as terrestrial planet, inner planet, rocky planet.
- Colour of moon is off white brown-grey
- The most widely accepted theory of moon’s origin, the giant-impact hypothesis.
- It has a diameter of 3475 km and its circumference is 10,864 km while its orbit is elliptical.
- It takes 27 days 7 hours and 43 minutes to rotate on its axis (the period of 27 ½ days is called the sideral month) and same period it takes to revolve around the earth.
- Only 59% of the total surface of the moon is visible from the earth and 41% is hidden part of moon
- Leibnitz situated on the south pole of the moon is the highest point on the moon.
- The temperature during day time is about 100oCelsius and during night it drops down to -180o
- The light from the moon takes 1 minute 3 seconds to reach the earth.
- The size of the moon is ¼ of the earth.
- Gravitational pull of moon is 1/6 that of earth.
- Silicon, iron, magnesium elements are found on the surface of earth.
- The bright part of moon is full of mountain surface whereas the dark patches are low lying plains.
- Sea of tranquillity (lower altitude plain) – the area of dark spot located in the northern hemisphere of the moon. It is made up of the plain of dust particles is on the rear side of the moon which always remain dark.
- The first manned Chandrayaan Apollo-11 landed on this part of the moon. In which Neil Armstrong and Edwin Aldrin landed/left footprints on the surface of the moon on 20th July 1969. It is also the location of the first moon colony in Emily St.
- Super moon– When a full moon is closest to the earth and appears 30%bigger and 15% brighter than normal moon. It is called Super moon.
- Blue moon– When in a month there are two full moons then the second full moon referred as blue moon.
- Blue moon year– When two blue appears in two or more than two months then it is referred as Blue Moon Year.
- Blood Moon- Name given for a view of the moon during a total lunar eclipse. Light passes through the earth’s atmosphere during an eclipse, red light from the sun is reflected on to it. The moons reddish colour earns its name called Blood moon.
- Lunar Tetrad- A sequence of four total lunar eclipses with no partial eclipse is called a Lunar Tetrad.
- Neil Armstrong, an American astronaut and astronautical engineer became the first person to walk on moon in 1969.
- Harrison Schmitt, was the last person who steps on moon in 1972.
- List of twelve astronauts who steps on moon: –
1) Neil Armstrong in 1969
2) Buzz Aldrin in 1969
3) Pete Conrad in1969
4) Alan Bean in 1969
5) Alan Shepard in 1971
6) Edgar Mitchell in 1971
7) David Scott in 1971
8) James Irwin in 1971
9) John Young in 1972
10) Charles Duke in 1972
11) Gene Cernan in 1972
12) Harrison Schmitt 1972
- Missions on moon: –
Chandrayaan-1-India’s first satellite. On 22nd October 2008 ISRO has successfully established Chandrayaan-1 in the moon’s orbit from Satish Dhawan Space Centre in Sri Harikota of Andhra Pradesh by Polar satellite launch vehicle PSLV C-1
Chandrayaan-2 -India’s second mission launched by ISRO from Satish Dhawan Space Centre in Andhra Pradesh on 22nd July 2019 by a LVM3-M1 rocket to moon which is a totally indigenous mission comprising of an Orbiter, Lander and Rover.
Chandrayaan-3– was launched by ISRO from Satish Dhawan Space Centre on 14th July 2023 and India became the 4th country to successfully land on the moon.