Space is like a container that engulfs everything and anything that we can see and touch. Space also includes things that we know physically exist but can't see or touch them. Astronomers define space as, the finite extension of 3D (three dimensional) region in which 'all matter' exists.

Now, in simple terms, outer space is space minus space under Earth's space (or Geospace).

Now, where does outer space starts?

There is basically no 'start' of outer space as such. Space of Earth (Geospace) gradually merges with the outer space. But for our easy understanding, scientists have accepted that 'outer space' begins at about 100 km above the earth's surface. This boundary is called the Karman Line.

See also

• Universe