Scientists now think that the Moon was formed when a Mars-sized object crashed into our Planet 4.5 billion years ago. The collision was so large that a huge spray of material was ejected into space. The orbiting ring of debris gathered itself into a sphere, and formed the Moon. How do we know that this is how the Moon probably formed? The Moon seems to be much less dense than the Earth and lacks a lot of iron in its core. Scientists think that the Moon is made up of the upper crust material, which has mostly lower density, than the composition of the Earth.
Although the Moon used to rotate in the sky compared to our point of view, it has been slowing down billions of years. And at some point in the distant past it just stopped turning from our perspective. The Earth's gravity holds the Moon in orbit, but it pulls differently at various parts of the Moon. Over a long period, gravity slowed down the Moon's rotation so that it finally stopped, and always displayed one face to the Earth. A similar situation has happened with most of the large moons in the Solar system. In fact, in the case of Pluto,Charon, but objects are tidally locked to each other, so they present only one face to the other.