Mysteries are delightful, perhaps diabolical, insistent and obsessive nags on the curious human imagination. What is the true nature of the Universe and what is our place in the inscrutable cosmic scheme of things? Can we answer these questions, or do they lie beyond our reach, perhaps hidden in secretive exotic corners somewhere beyond the cosmological horizon of our visibility? Indeed, domains that exist beyond our cosmological horizon are so remote that the light traveling to us from those regions has not had the time to reach us since the inflationary Big Bang birth of the Universe almost 14 billion years ago because of the expansion of Space. Wandering to us throughout the incredibly vast swath of Space and Time, the Cosmic Microwave Background (CMB) radiation carries bewitching clues about what happened long ago and far away in the first magnificent instants of the baby Universe’s mysterious birth. This background radiation of ancient light is the relic thermal radiation left over from the primordial era of recombination in Big Bang cosmology, and it is a tattle-tale–it gives away the most profound secrets of our Universe to those who live in our cosmic Wonderland. In September 2016, a team of astrophysicists revealed that their study of the CMB radiation shows that the Universe expands the same way in all directions–it has no preferred direction at all.
This new research, published in the September 22, 2016 issue of Physical Review Letters, supports assumptions made in the cosmological Standard Model of the Universe. The lead author of the study, Dr. Daniela Saadeh, commented in a September 22, 2016 University College London Press Release that “The finding is the best evidence yet that the Universe is the same in all directions. Our current understanding of the Universe is built on the assumption that it doesn’t prefer one direction over another, but there are actually a huge number of ways that Einstein’s Theory of Relativity would allow for space to be imbalanced. Universes that spin and stretch are entirely possible, so it’s important that we’ve shown ours is fair to all its directions.” Dr. Saadeh is of the University College London’s Department of Physics and Astronomy in England.
The CMB is a ghostly, gentle glow of very ancient light that pervades the entire Universe. It streams softly through Space and Time with an almost unvarying intensity from all directions–and it is the relic afterglow of the Big Bang itself. This primordial light that lingers whispers to us some very haunting long-lost secrets about an extremely ancient era that existed long before there were observers to witness it. The CMB is the oldest light that we are able to observe. It began its long journey to us 13.8 billion years ago–billions of years before our Solar System had 海外留學 formed, and even before our barred spiral Milky Way Galaxy had formed, spinning like a starlit pin-wheel in Space. The CMB comes to us from a vanished era when all that existed was a turbulent sea of fiery, dazzling radiation and a wild, rushing, screaming flood of elementary particles. The ancient Universe was not the comparatively cold and quiet place that it is now, and the more or less familiar inhabitants of the Universe–stars, planets, moons, and galaxies–all eventually formed from this newborn flood of elementary particles, as the Universe greatly expanded and became increasingly colder and colder. We now look upon the Universe’s dying glow–the lingering ashes of its mysterious fiery formation–as it rushes ever faster and faster to its unknown fate.
The CMB is an almost-uniform background of radio waves that floods the entire Cosmos. It was released when the Universe had finally cooled off enough to grow transparent to light and other forms of electromagnetic radiation–about 380,000 years after its Big Bang birth. The primordial Universe was then brimming with searing-hot ionized gas. This gas was almost entirely uniform, but it did possess some exquisitely tiny deviations from this ancient uniformity–strange spots that were only very slightly (1 part in 100,000) more or less dense than their surroundings. These very small deviations from complete uniformity provide astrophysicists with a gift of sorts–a map of the primordial Universe–the CMB radiation. This precious, beaming afterglow of our Universe’s vanished babyhood contains the lingering fossil imprints left as a legacy of those ancient particles–the pattern of very, very small primordial intensity variations from which scientific cosmologists can try to determine the attributes of the Universe.