The CBR was discovered by two telecommunication scientists working with satellite technology. They found a strange, constant, low level of interference and subsequently discovered it was coming from all directions. Suspecting pigeon droppings in the receiver, they cleaned it out but the signal remained. Concluding it came from the sky, they had actually discovered the remnant radiation from the explosion that created our Universe.
In its infancy, the Universe was composed almost entirely of hydrogen atoms, a period of rapid expansion followed allowing the universe to cool which allowed the seething mass of energy to slowly change into matter. Eventually, great clouds of hydrogen gas collected under the force of gravity which led to the formation of the first generation of stars, gravitationally bound together into islands in space, the galaxies. The first stars were hydrogen rich and, as a result of nuclear processes in their core, slowly over time they produced heavier elements, including nitrogen, oxygen and iron. At the end of the stars lives, they exploded, seeding space with the newly generated elements which would then go on to form the second generation of stars. Along with the next stars, the heavy elements would form planetary systems and ultimately life.
As the universe evolves with stars, and perhaps life coming and going, it’s fate is less certain. Until recently we thought that the expansion of the universe from the initial Big Bang would do one of two things depending on how much material existed (more material means more gravity). If there is a lot of material then the total force of gravity may be enough to slow the expansion, stop it and even reverse it so the Universe starts contracting. It may be that there isn’t quite enough gravity so it will just continue to expand but get slower and slower.
Recent observations have shown that its likely that neither of these fates await the Universe. It seems that the rate of expansion of the Universe is actually getting faster and faster, not slower and slower! This means there must be some previously unidentified force driving the expansion. Its now thought that at the tiniest scale, particles are popping in and out of existence generating a tiny pushing force on the Universe and it’s thought that this is causing the Universe to expand ever faster. Either way, it looks like the fate of the Universe in billions and billions of years will be a very cold and dark place.