What is outer space made of?

From the perspective of an Earthling, outer space is a zone that occurs about 100 kilometers (60 miles) above the planet, where there is no ... read more

Outer space, or just space, is the expanse that exists beyond the Earth and between celestial bodies. Outer space is not completely empty—it is a hard vacuum 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. read more

Outer space contains a low density of particles, primarily hydrogen gas, along with electromagnetic radiation. Many people, however, mistakenly believe outer space is a complete vacuum. The term"outer space" is used mainly to distinguish the space between planets from the planets and their airspace. read more

Outer Space, or space which lies beyond the Kárman line (assumed line at 100 km altitude from surface of Earth), is mostly empty space, or vacuum. It's not completely empty - average density of matter is 10 atoms in one cubic meter of space. read more