Where does outer space begin? – The Clare People - The Clare People

If someone asked you to indicate where outer space begins, what would you do?

Lemaître suggested that if the expansion of the universe could be projected back in time (like a VHS tape rewinding from end to end beginning), it would be smaller.

When we think of the Big Bang, for example, we may have a tendency to imagine that it took place in some specific place in the universe, a place where we cannot see even with large telescopes, due to the staggering distance.

This notion can intensify when we read news about objects like quasar J660-1806, located more than 22 billions of light years away from Earth, and almost as old as the universe.

But we have to consider one very important thing: the Big Bang is not an explosion that spread matter through space — it is space itself!

This means that you, me, the Earth, the Sun and the Milky Way are just in a space that already existed at the Big Bang, but that has expanded enough to fit all these cosmic objects that enchant us during a night clear of clouds and fog.

This is why we cannot point to the direction where the Big Bang occurred.

It is also for these same reasons that the cosmic background radiation (the “fossil” of light left over from the Big Bang) is observed in any direction in space where we look—with large telescopes, of course.

This is also true for “where does space outside Earth begin?”, because the Earth is immersed in this space, which is the very expansion that resulted from the Big Bang.

The space where our little one The pale “dot” we call a planet already existed in the Big Bang.

We are in the same universe, where the space between galaxies increases, and where energy and matter are changing all the time.

The boundary between our atmosphere and outer space (from the English “outer space”, which literally means “outer space”) is also quite relative.

Therefore, countries define their own limits and the laws that govern airspace and outer space are different.