Big Bang continued...

Another reason why the Big Bang is a plausible theory is according to the CMB radiation observed by Arno Penzias and Robert Wilson in 1964, for which they rightfully deserved the Nobel Prize in 1978.

With a traditional optical telescope, the space between stars and galaxies (the background) is completely dark. But a sufficiently sensitive radio telescope shows a faint background glow, almost exactly the same in all directions, that is not associated with any star, galaxy, or other object. This glow is strongest in the microwave region of the radio spectrum. At first, Penzias and Wilson thought it was an error, and even cleaned up the telescope of pigeon droppings. But then, when the glow persisted, they realised that it had to come from the Universe itself, and was almost exactly the same on all sides.

What is CMB radiation?

CMB radiation stands for Cosmic Microwave Background radiation. It is the after glow of the Big Bang, the residual energy that was released during the moment of creation.

But how is this related to the Big Bang?

The Universe is vast, far greater than what we can observe with even the most sensitive, powerful telescopes. The CMB radiation observed is almost equal from all sides. That means that the residual energy is more or less evenly spread out all over. But since nothing can travel faster than light, that means heat can't either. This implies that if the Universe was always this big, then the heat wouldn't have enough time to radiate in all directions equally, leading to HUGE holes in the detected radiation.But it is all even. That means that at some point of time in the past, the Universe was relatively close together, close enough for the heat to flow even to all points.We know the state of the Universe today, and we can calculate the distance the Universe must have had to have the heat flow evenly. Joining these two 'points', we can say with enough evidence that at some point of time, or the zero time, as physicists refer to it, the Universe was compressed into a zero space (not exactly zero, but the nearest possible). This then exploded, or expanded, or inflated, whichever you prefer, into the Universe we know today.

That, my dear friends, is the Big Bang.