The Cosmic Microwave Background (CMB) radiation is the most ancient light that can be observed. This primordial, wandering light began its long, treacherous, mysterious journey nearly 14 billion years ago–and it is an almost-uniform background of radio waves that flow throughout the entire Universe. The CMB was liberated very long ago, when the newborn Cosmos had at last cooled down sufficiently to become transparent to light and other forms of electromagnetic radiation, approximately 380,000 years after the Universe was born in the wild exponential inflation of the Big Bang. The Cosmos keeps its secrets well. One of its best-kept secrets involves a bizarre region of the sky observed in these primordial microwaves that astronomers have found to be mysteriously large and cold compared to what they usually expect to observe. This enormous Cold Spot has defied explanation–and, as such, it well may have an exotic origin, such as being the tattle-tale result of a primeval collision between our Universe and another universe inhabiting an incomprehensibly vast Multiverse. In 2016, a team of astronomers offered a new explanation for the mysterious origin of this enormous Cold Spot.
Many astronomers have proposed that this strange feature is a supervoid. A supervoid is a vast region of Space that contains very few galaxies. In the distant reaches university of western australiaof the space between galaxies, there are strange and lonely corners that are almost entirely bereft of everything except atoms. In these immense regions, only atoms–haunting a haze of hydrogen gas left over from the Big Bang–occupy these almost barren regions, which are the voids. On the largest scale, this diffuse material is arranged in a network of filamentary structures called the “cosmic web”. This immense structure resembles the web university of western australia woven by a gigantic spider, and it is spun from invisible material known as the dark matter. The dark matter is composed of exotic, non-atomic, and as yet unidentified particles. The gigantic, massive filaments of the invisible cosmic web are outlined by a multitude of starlit galaxies, while the voids are almost entirely empty. The entire immense structure, that resembles a natural sponge or, perhaps, a familiar honeycomb, appears to be composed of heavy dark matter filaments and almost barren voids that are wrapped around one another. Some astronomers have suggested that the entire cosmic web is really composed of only one enormous filament and one gigantic void, tangled up together into a complex structure.
The Bootes void or the Great Void is one example of a supervoid. It is an immense, approximately spherically shaped region of space that hosts very few galactic constituents. It is situated in the vicinity of the constellation Bootes, from which it derives its name. The Bootes void is approximately 330 million light-years in diameter, and is one of the largest known voids in the Universe. Its discovery was reported by Dr. Robert Kirshner et al. back in 1981. Dr. Kirshner is of the Clowes Professor of Science Emeritus at Harvard University in Cambridge, Massachusetts.
However, a supervoid is unlikely to explain the origin and nature of the Cold Spot in the CMB, according to the results of the new survey. If it is determined that the Cold Spot is not a supervoid, then it is time for scientists to consider more exotic explanations. The researchers, led by postgraduate student Ruart Mackenzie and Dr. Tom Shanks in Durham University’s Centre for Extragalactic Astronomy, publish their results in the October 2016 issue of the Monthly Notices of the Royal Astronomical Society (MNRAS). Durham University is in Durham, UK.