The solar system

Outer space (or simply space) is the expanse beyond celestial bodies and their atmospheres. Outer space is not completely empty; it is a near-perfect vacuum[1] containing a low density of particles, predominantly a plasma of hydrogen and helium as well as electromagnetic radiation, magnetic fields, neutrinos, dust, and cosmic rays. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins (−270 °C; −455 °F).[2]