Another Day on Earth was created on 2005-06-13.

Mercury rotates once in about 59 Earth days. That is often called its "day".

There's another definition of day called the "solar day". For Mercury that's 176 Earth days.

So, you can see there's only a small fraction of a Mercury day in one Earth day.

because the earth faces the sun and on the back of the earth is facing to the moon

Night and day are merely the most obvious. Wind is another.

It's to do with the length of time a planet takes to spin, a planet that spins on its axis faster than the earth will have a shorter apparent day.