Space is almost a perfect vacuum, the region between celestial bodies filled with radiation, particles, dark matter, and energy. It begins approximately at the Kármán line.
Interesting factsThe age of the Universe is about 13.8 billion yearsThe observable Universe has a radius of about 46.5 billion light-yearsThere is no sound in space because there is no medium to carry sound wavesSpace is not completely empty - it contains ions, hydrogen atoms, and cosmic rays.