The air that covers the whole of the earth like a blanket is called the atmosphere. The atmosphere is an important part of What makes earth livable. It blocks some of the sun's dangerous rays from reaching earth. It traps heat ,making earth comfortable temperature. And oxygen within our atmosphere is essential for life .The atmosphere keeps the average temperature of the earth fairly steady during the day. The atmosphere prevents the sudden increase in temperature during the day light hours and during the night it slows down the escape of heat into outer space.