The Dark Side of the Moon
The Dark Side of the Moon.
P.K.Ghatak,MD
Blog No.61.
The moon is admired by poets and voyagers unmatched by others, even perhaps, those scientists engaged in their moon missions. In the old days the villagers and seafarers knew much more about the moon than recent science graduates. Most young men look moon with the same concerns as their mothers – they know she will be there for them when they need her and in between times, just benign neglect. This is not the worst; in the world literature there are instances where the dark spot on the moon is compared with slip of moral character of the beautiful girls and young women.
It was not until the Soviet mission Luna 3 flew past the far side of the moon and photographed. It showed more rugged and have higher density of craters.
The Apollo mission of the USA No. 8, 10, 11 13,16 and 17 of the USA flew by the far side of the moon and photographed this side.
China came next. Her mission, Chage 4 landed on the far side of the moon in 2019 and followed by another in 2024.
The far side in the prime location for placing a Radio telescope because this side is shielded from the radio noise from the Earth.
India is the latest county successfully landed their craft Chandrayaan 3 in 2023 in a difficult spot on the north pole of dark side of the moon. The mission discovered presence of water molecule in the ice in the shade. It also found evidence of Sulfur but no hydrogen molecules. The presence of sulfur means, the surface of the moon came from larval core of the earth like planet. A much thicker layer of Charged Particles surrounds the moon.
The scientists were surprised to find much cooler temperature (minus 10C) just 3 inches below the surface, the nighttime temperature on the surface dropped to minus 120degrees C (-120C), the daytime surface temperature 70C. The surface materials of the moon act as insulator and can be used as insulator for homes build on the moon. It is really commendable that all this information is in the public domain and quite unlike other nations.
In recent years a great competitive rivalry between nations grew to make a permanent base in the moon. The goal is not only scientific but also gain access all the untapped minerals and energy for building colony in other planet in the future.
However, no one can honestly say what they say is that what they mean. In the present political turmoil and rivalry for military dominance between nations, this project may be a decoy for establishing a military outpost on the moon.
Why the other side of the moon is not visible from the Earth:
The moon rotates on its axis and also goes around the Earth. Using Earth's time, the moon takes 29.5 days to complete one rotation around its own axis and the same 29.5 days to go around the Earth. In other words, a moon day and a moon year take equal time to complete. The unseen side pf the moon also gets the same amount of sunlight and is equally bright. Just we do not able to see or any other ways to communicate with that side. It is better to call the dark side an unseen side or far side of the moon.
This is the reason, looking at the moon standing anywhere on the Earth one sees the same face of the moon. The scientists call it Tidal Locking.
The shinning area on the moon varies and called the Waxing (Grow)and Waning (shrink) phages of the moon. Each day the angel shifts relative to our visual path, changing the portion of the sunlight directed towards our visual path, like a child, playing with a mirror and angling it various ways to annoy his friend on a sunny day on the beach.
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Footnote:
In general, we see one side of the moon, but it is not 50% of the moon, we actually see 59 %.
How this happens:
There are 4 factors involved.
1, The moon makes an elliptical path around the earth and goes faster when closest to the earth and moves ahead of its axial rotation. (Axial and Orbital rotations take equal time) This allows us to see additional 7 degrees around the eastern and western edges of the moon.
2, Moon's pole is tilted 6 degrees relative to the Earth's plane. For two weeks one pole of the moon tilts towards us and the next two weeks the other pole is tilted towards us. The pole that tilts, allows us to see additional area above the pole.
3, When moon rises, we see from close and moonset we see the moon from furthest distance. We are carried from one side of the earth-moon line to the other by the rotating Earth. With the change of our visual path and this allows additional part of the moon to our view.
4, When moon appears as a crescent, reflected sunlight from the Earth falls on the dark side of the moon and we can see slightly more of the moon when it rises than when it sets.
Why Ocean Tide happens:
Moon- on this side.The gravitational force of the moon pulls the water and all other material on the earth towards it, even though the mass of the moon is only 1/10th of the Earth. The Earth's gravity keeps things in place, but water being more mobile bulges out towards the moon,
As the Earth rotates along its axis, a part of the Earth comes under the maximum zone of moon's gravity and this causes high ocean tide, as this part moves away high tide recedes and low tide begins. This happens one a day.
The opposite side of the Earth, water also bulges outwards but to a lesser extent. The diagram explains this differential pull.
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