In the 16th Century, the Polish Astronomer Nicholas Copernicus thought that the sun was the center of the Universe with Earth and the rest of the planets circling it. However, today we know that there doesn’t seem to be a center of the universe and that it is much more vast than Copernicus could ever have imagined.
Since the Big Bang, our universe has been continuing to expand. And this is where some confusion lies. The ‘Big Bang’ sounds like an explosion but if it were, it would have had a central starting point, rather like that of a bomb. The Big Bang didn’t start from a particular point in space because before the Big Bang there was no space...and this is where it gets a little tricky to understand. What the term Big Bang actually means is that about 14 billion years ago a massive ‘happening’ occurred which brought time and space into existence.
So, how do we know that the Big Bang happened at all? Scientists are able to detect faint traces of background cosmic radiation from the birth of time and space. Using a special telescope Scientists have been able to make more and more measurements to support the Big Bang theory. The radiation is sort of like ‘noise’ left from the beginning of the universe and the information we have today was originally gathered by the Cosmic Background Explorer spacecraft in the early 1990’s.
(Courtesy COBE Science Working Group/NASA Goddard Space Flight Center)
This image shows radiation left over from shortly after the Big Bang. Intensity variations are shown by the different colors – Scientists believe that where the colors are most dense these are the areas newly formed matter most likely formed into groups of galaxies.
If you’re in any doubt just how vast the Universe is, have a look at the following video .. while it’s only a simulation, it does give you an idea of how tiny we are compared to the great giants of space.