Do you remember the white noise that came on television channels when no station was available? It apparently carried a tiny afterglow of the Big Bang. The static hiss contained at least 1 per cent of cosmic microwave background (CMB), a remnant of the birth of the universe 13.8 billion years ago. Not only on TV, but the same noise was also heard on radios. Everyone alive at the time these analogue televisions existed inadvertently time-travelled, in the sense that they witnessed the Big Bang, the universe’s past. A sliver of CMB seeped through this disturbance and into our homes, without us even realising it. Cosmic microwave background radiation was discovered decades ago by astronomers Arno Penzias and Robert Wilson. Later, Robert Dicke at Princeton University found that the CMB was nothing but a faint, cold afterglow of the Big Bang.
In 1964, Penzias and Wilson were disturbed by a stubborn hum in their radio telescope while working at Bell Labs, Holmdel, New Jersey. They were trying to listen to the microwave signals transmitted from our Solar System using a large radio antenna. But a background hiss kept interfering. They tried to locate the source so that it could be removed. They assumed it could be radio signals from nearby cities, and even checked the antenna for pigeons. Penzias and Wilson spent one year trying to figure out what this noise was and where it was coming from. Their work revealed that the universe was awash with microwaves at a temperature of around three degrees above absolute zero. However, they did not know the actual source of this noise.
Dicke and his colleagues worked to find the afterglow of the Big Bang to prove that this is how the universe was formed. Cosmic microwave background radiation turned out to be missing evidence that backed the Big Bang. The universe was hot and dense in the beginning, and started expanding and cooling later. Around 380,000 years later, photons started moving across the cosmos and formed the CMB. The old antennas we used for televisions picked up this radiation, a piece of the birth of our universe. The rest of the noise came from earthly sources and the sun. As digital transmission took over, this hiss started dying out.