17.1 The earths atmosphere is a mixture of gases Our atmosphere is a result of actions of both heat and gravity ※:※ (a)Atmospherewith gravity but no (a) Atmosphere with solar heat but(a) Atmosphere with solar heat and solar heat: molecules lie on the no gravity: molecules escape into gravity: molecules reach high earth's surface outer space altitudes but are prevented from escaping into outer space Fig 17. 1 our atmosphere is a result of the actions of both solar heat and gravity17.1 The Earth’s atmosphere is a mixture of gases. Our atmosphere is a result of actions of both heat and gravity (a) Atmosphere with gravity but no solar heat: molecules lie on the earth’s surface (a) Atmosphere with solar heat but no gravity : molecules escape into outer space (a) Atmosphere with solar heat and gravity : molecules reach high altitudes but are prevented from escaping into outer space Fig 17.1 our atmosphere is a result of the actions of both solar heat and gravity