The Moon, or if you are hungry the bright cheese...

The only natural satellite of earth is moon and is about 384,000 kilometers away from earth. This value was measured quite accurately by the ancient Greek astronomer Hipparchus, who lived in the second century B.C.E.

The formation of the Moon remained a mystery for many years. It was once thought that Earth and the Moon might have formed simultaneously as two separate objects, bound together by their mutual gravitational pull. Not long ago, scientists have shown that the most likely scenario of how the Moon formed involves the collision of two planetary bodies. Billions of years ago, before life formed on Earth, a Mars sized protoplanet hit the Earth. Most of the material in the protoplanet fell into, and became part of, our planet, some material however, was thrown out into space, and began to orbit Earth as a ring of dust and rock. A huge portion of that ring of material came together to form the core of our Moon. Over millions of years, the Moon took its present-day size and shape.

The craters on the Moon’s surface were formed after it was struck by great numbers of meteorites. The first to study the universe with a telescope, was Galileo Galilei, observed that the moon’s surface wasn’t smooth. An early-age astronomer who mapped 250 craters and other surface features on the moon was Johannes Hevelius, the founder of lunar topography.

Over billions of years, the rotation of the Moon has become synchronized with its orbit around Earth and the same side of the Moon always faces our planet, so the “dark-side” of the moon is the side that always faces away from Earth.

Moon seems bright as the Moonlight is reflected sunlight. This was discovered by the ancient Greek astronomer Parmenides, at about 500 B.C.E. Since Earth and the Moon are so close together, and since the Moon has such a shiny surface, large amounts of sunlight come to Earth after bouncing off the Moon.

The reason that moon seems to change shape is because Earth orbits the Sun, whereas the Moon orbits Earth, so the relative positions of the Moon, Earth, and the Sun keep changing. This kind of regular changing pattern causes the phases of the Moon.

Image References:

1. simple.wikipedia.org
2. blogs.esa.int
3. giphy.com

Text references

1. en.wikipedia.org/wiki/Moon
2. space.com
3. newscientist.com