The Planet Earth has its own Force of Gravity and Air Pressure
The air and the wind around the earth play an important role in the lives of all creatures. Breathing is necessary for all living creatures on the earth. If this air pressure changes then the creatures can not take a breath. The importance of air can be determined by stoping breathing for few seconds. In such a case, Oxygen does not reach the inner body so a human can start to die. The air space around the earth contains 21 percent Oxygen. It is so interesting to mention here if the percentage of Oxygen reaches 50 percent then all fire flamming material can start to burn. If this percentage decreases then all creatures on the earth could not take a breath and could die.
All the air found on earth and around the earth contains a good Oxygen percentage. But if we travel towards height 10 Kilo Meters or more then breathing can be impossible so easily. In airplanes, the Oxygen system is maintained at the natural level. Newton was the first who discovered the force the gravity which can not be seen. If the force of gravity does not exist then the air should also not exists. If gravity does not exist in the space between the stars and planets, then all the planets and stars could collide.