In 1964, two researchers from Bell Labs were monitoring the sky with their radio telescope.
They were hoping to detect signals from gaseous nebulae, light years from earth, but instead they picked up something very strange.
The signals were in the microwave portion of the spectrum, at frequencies much lower than they expected.
How could this be? Gas clouds weren’t known to emanate microwaves.
They wondered…where were these signals be coming from if not from gaseous nebulae?
To make the long story short, the Bell investigators were witnessing the first light ever produced by the universe…a mere 380,000 years after the Big Bang, a time when the universe was less than one tenth of 1% its present age.
But, as noted earlier, the scientists observed microwaves…not light.
The reason: the waves of that very first light, were stretched out as the universe expanded. When wavelengths of light are increased, stretched out, their frequency is decreased and they are transformed from light into microwaves.
These scientists had inadvertently discovered what came to be known as the Cosmic Background Radiation.
It lent further credibility to
the Big Bang as well as demonstrating that the universe was rapidly expanding, beginning first instant after the Big Bang.
In tuning in the CBR, they were detecting the afterglow of the Big Bang.
If you still have an old analog TV, the snow that appears on the screen when you tune to blank channels is also the cosmic background radiation.