What is the difference between 'inner space' and 'outer space'?

Answer 1

In reality, there is just space. Space is actually everywhere around us. It consists of three dimensions of length, width, and depth. We can move forward-backward, left-right, and up-down. There is space above the earth which includes its atmosphere, on its surface, and under the earth. We happen to live on the planet's land surface but inside its atmosphere. The terms 'inner space' and 'outer space' are arbitrary. In fact, such terms can apply to any body in the universe, whether it be a planet, a star, a moon, etc. We usually use the term 'outer space' to refer to the black void above Earth's atmosphere where all the other physical bodies in the universe are located. Most scientists don't use the term 'outer space' and instead just use the term 'space' to refer to this region. And exactly where 'outer space' begins is arbitrary. The higher one ascends into the atmosphere the less air molecules there are to scatter sunlight and the darker the sky becomes. The sky gradually changes from bright blue near the earth's surface to a darker blue higher up before eventually darkening to black. Where there is no air there is a vacuum. And if there are no air molecules to scatter the light, you will only see blackness. We actually have a grandstand view of this dark, airless region in a cloudless sky here on Earth every night away from light pollution. And it is a sight to behold. It is enormously huge, even possibly infinite. We can also use synonyms such as 'the heavens', 'the sky', 'the night sky', 'the cosmos', or 'the universe'. 'Inner space' on the other hand may refer to any of the interior regions of the earth, but more specifically to the ocean depths underwater. 'Inner space' may also be used abstractly to refer to the spiritual or mental aspect of humans. This is a rare term that is seldom found in most English dictionaries.