Image bigbang

The Big Bang

We now know, from astronomical observations, that most galaxies are moving further apart from each other; according to scientists this can be explained by the fact that the Universe is not immobile but has been expanding for more than 13 billion years following a single event which is known as the Big Bang.

However, this expansion doesn’t have a true centre. Looking at the figure will help to understand this statement, which at first may seem surprising: on the left there is a circle represented by a party balloon with two big dots on its surface. Imagine that the balloon is blown up a little more, as represented by the circle on the right, we can see how the two dots would grow further apart from each other.

If we were one of the two dots, we would be under the impression that the other dot was moving away, while the other dot would be thinking that we were moving away from it.

If we imagine that the Universe is the balloon, and the two dots are two galaxies, we would come to the following conclusion: to a hypothetical inhabitant of a galaxy it would seem that all the other galaxies were moving away from his/her galaxy. The point is that it is impossible to determine the centre of this expansion.

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