Scientists say: We never see other side of moon from the earth. Why? It's a chance or a science principle?

It's a scientific principal. The Moon is tidally locked to the Earth. What this means is, the gravitational phenomenon of tidal interaction has acted like a kind of friction on the Moon, causing it to slow down until its orbital period about the Earth matched its period of revolution about its own axis. The result is that the same side of the Moon always faces the Earth, and we can only see 59% of the Moon's surface from Earth. We can see slightly more than half because the Moon does have a bit of wobble to it, called libration.

Because of tidal friction, the rotation of the moon slowed to one revolution per month, so that the same side always faces us. Similar tidal forces are acting on the earth, also slowing its rotation down. This happens to any small body orbiting a larger body; for example, mercury always has the same side facing the sun. The reason that the final result is that way, is that there are no tidal stresses in the moon when it doesn't rotate with respect to the earth.

The Motion of Moon has altered over Millions of Years in such a way that it always has one side facing Earth .

only one side of the moon faces us and due to the way it rotates we never see the other side

one day on the moon is as long as a year on the moon

Here's why:

http://www.jimloy.com/astro/moon4.htm

ofcourse! its true coz u just imagine can u see the other side of a ball by taking it in ur hand? just think it!!

of course its true coz that's what they say...