Sphere

The Earth that sustains us may be considered in terms of different spheres. There is the lithosphere, made up of the rocky foundations of our planet; the hydrosphere, representing our planet’s water; and the cryosphere, comprising the frozen polar regions and high mountains. The atmosphere is the air we breathe, and we are also part of the biosphere, made up of the Earth’s living organisms. These spheres have been in existence, in one form or another, for most, or all, of our planet’s 4.6-billion-year existence. Most recently, a new sphere has emerged – the technosphere.
-- unesco.org