The envelope of gases surrounding the earth's crust is called

The envelope of gases surrounding the Earth's crust is called the atmosphere. The atmosphere is a layer of gases that surrounds the Earth and is held in place by gravity. It is composed of various gases, including nitrogen (78%), oxygen (21%), and other trace gases such as carbon dioxide and helium. The atmosphere plays a crucial role in regulating the Earth's temperature, protecting it from harmful radiation, and providing the air we breathe. It is divided into five layers based on temperature, with the troposphere being the layer closest to the Earth's surface and the exosphere being the outermost layer. The hydrosphere refers to all the water on Earth, including oceans, lakes, rivers, and groundwater. The lithosphere refers to the solid outer layer of the Earth, which includes the crust and uppermost part of the mantle. The barysphere refers to the Earth's core, which is composed of primarily iron and nickel.