What is Cosmic Microwave Background Radiation?

The Cosmic Microwave Background radiation, or CMB for short, is a faint glow of light that fills the universe, falling on Earth from every direction with nearly uniform intensity. It is the residual heat of creation–the afterglow of the big bang–streaming through space these last 14 billion years like the heat from a sun-warmed rock, reradiated at night.

The Cosmic Microwave Background (CMB) is the cooled remnant of the first light that could ever travel freely throughout the Universe.

This ‘fossil’ radiation, the furthest that any telescope can see, was released soon after the ‘Big Bang’.

Scientists consider it as an echo or ‘shockwave’ of the Big Bang. Over time, this primeval light has cooled and weakened considerably; nowadays we detect it in the microwave domain.

ESA’s Planck mission will detect this first light, which is also the ‘oldest’ radiation detectable and carries information about our past and future. By observing it, Planck will be seeing the Universe as it was almost at its origin.

Cosmic Microwave Background radiation

When was Cosmic Microwave Background Radiation Discovered?

Humanity’s understanding of the universe took a giant leap forward 50 years ago today.

On May 20, 1964, American radio astronomers Robert Wilson and Arno Penzias discovered the cosmic microwave background radiation (CMB), the ancient light that began saturating the universe 380,000 years after its creation. And they did so pretty much by accident.

Bell Labs’ Holmdale Horn Antenna in New Jersey picked up an odd buzzing sound that came from all parts of the sky at all times. The noise puzzled Wilson and Penzias, who did their best to eliminate all possible sources of interference, even removing some pigeons that were nesting in the antenna.

How was Cosmic Microwave Background Radiation Discovered?

Cosmic background radiation is electromagnetic radiation from the Big Bang. The origin of this radiation depends on the region of the spectrum that is observed. One component is the cosmic microwave background.

This component is redshifted photons that have freely streamed from an epoch when the Universe became transparent for the first time to radiation. Its discovery and detailed observations of its properties are considered one of the major confirmations of the Big Bang.

The discovery (by chance in 1965) of the cosmic background radiation suggests that the early universe was dominated by a radiation field, a field of extremely high temperature and pressure.

The Sunyaev–Zel’dovich effect shows the phenomena of radiant cosmic background radiation interacting with “electron” clouds distorting the spectrum of the radiation.

There is also background radiation in the infrared, x-rays, etc., with different causes, and they can sometimes be resolved into an individual source.

What does cosmic radiation do to the human body?

Space radiation can lead to other effects. Radiation can alter the cardiovascular system, damaging the heart, harden and narrow arteries, and/or eliminate some of the cells in linings of the blood vessels, leading to cardiovascular disease.

Radiation exposure can hinder neurogenesis, the process of generating new cells in the brain. If neurons or supporting cells are damaged or killed, there is less potential for the development of new cells, especially at the rate a person would need to minimize or eliminate the damage. In the central nervous system, this could lead to cognitive impairment and memory deficits.