What Is Space?
The Final Frontier
That is a difficult question, with several answers! Space is everywhere and in every direction, with no limit as far as scientists can tell. The majority of space beyond Earth’s atmosphere between the planets, stars and galaxies is dark, cold and almost a complete vacuum. So you can’t breathe or talk to other people in outer space like you can on Earth!
A Short Summary Of What ‘Space’ Is Thought To Be!
When most people talk about space, they are referring to the region beyond Earth’s atmosphere (which ends about 100 km above Earth’s surface) and extends to the planets, stars and distant galaxies.
Space also appears black as there is no atmosphere to scatter and improve sunlight, so you can easily see the light from distant stars. No atmosphere in space also means it is boiling hot in direct sunlight, yet gets very cold as you travel further from a star like the Sun! These are the main reasons why humans can’t survive in space without a special spacesuit!
Space is often said to be a vacuum too, but it isn’t completely empty as there is dust and gases (like hydrogen) floating around in the space between stars (called interstellar space) and galaxies (called intergalactic space). However, there isn’t enough gas in space for sound to travel through it, so space is silent to a human. Only electromagnetic waves like radio, infrared, light along with many hazardous ones to humans such as X-rays and gamma rays, can easily travel through space.
There are more complicated ways to answer the question ‘What Is Space” which relate to Einstein’s general theory of relativity. In this case ‘time’ is a part of the fabric of space and is referred to as spacetime. According to Einstein’s theory, objects of great mass such as big stars and galaxies affect the spacetime fabric - warping and bending it.
A result of the warping of spacetime is the formation of gravity and distortion of time (i.e. time slows for those near large masses compared to those further away) which was once thought to be a constant throughout space! Extreme warping of space (spacetime), by massive and dense objects, leads to the formation of black holes in space!
According to cosmologist, space (which the universe occupies) was created during the Big Bang and has been expanding, at an increasing rate, ever since for reasons that aren’t fully understood yet, but maybe related to the presence in space of dark matter and dark energy!
This makes you wonder what existed before the Big Bang when no space existed?!