Sound travels to our ears by vibrating air molecules which are present all around us. Now no atmosphere means no air. Hence, there would be complete silence.<br />Secondly, no atmosphere means no oxygen, life on land would not last for more than 5 minutes. But life inside oceans might continue for some time as fishes will use dissolved oxygen to survive. Eventually even that supply will run out.<br />Thirdly, no atmosphere means no clouds, our sky would lose its magnificent blue color, it would look just as black as outer space.<br />Fourthly, unfortunately birds can't fly in vacuum, they will drop down to earth.<br />Lastly, without any atmosphere, days would be shorter by 4 minutes while nights longer as atmospheric refraction advances sunrise by 2 minutes and delays sunset by 2 minutes.
