SPACE: MOON

 The moon:

    Our closest neighbour in space, the Moon, has been orbiting the Earth for almost 4.5 billion years. According to one theory, an object the size of Mars would have crashed on the young Earth, dispersing a huge cloud of matter into space, which would then condense to form the Moon. As the Moon is smaller than the Earth, its gravity force is weaker and does not allow it to retain air or water. Without an atmosphere to protect it, the Moon is hit by all kinds of planetary objects that leave deep traces on its surface. On the Moon, the dark areas are called maria or seas; they have been shaped by meteoric impacts of an unheard of force, making erupt lava that has solidified at the bottom of the craters.

The phases of the Moon:

  Of itself, the Moon does not diffuse acune light. If we can see it, it is only because it acts as an immense mirror reflecting the light of the Sun. As the Moon revolves around the Earth, it seems to take different forms, because we only see its sunny side. These various forms are called phases. It takes 29.5 days for the Moon to pass from one full Moon to the next.

Rising of the Earth:

    The astronauts of Appolo 8 were the first humans to see the Earth rise and lie down when they were in orbit on the Moon in December 1968. They described the blue and white Earth as an oasis in space, compared to the arid grey surface of the Moon.

The craters:

    The surface of the Moon is shaped by craters whose dimensions vary from the smallest depressions to immense basins with a diameter greater than 200 km. The craters are generally circular in shape, bordered by garlands walls created by the debris ejected during the impacts. Most of them have a central piton, where the crust bounced after the collision. The young craters have rays of ejected material that have been sprayed into bright nets.

The Hidden Side:

    As the Moon turns on itself only once as it moves in its orbit around the Earth, we always see the same face. Its hidden face remained a mystery until the second Russian spacecraft "Luna 3" passed behind the Moon and sent the first images in 1959. Of a very different appearance from the visible face, it shows more craters but less dark seas, because its crust is thicker and it can better withstand the big bombardments. Many of these craters bear the name of a scientist, like that of Pasteur.

Notes: 

● Distance from Earth to the Moon: 384,400 km. 

●Apollo 11 took 3 days to reach the Moon at a speed of 38,916 km/h. 

●Spacecraft escape Earth’s gravity at 62,550 km and are attracted to the Moon.