Wonders of the Universe - Brian Cox [30]
This detailed picture of the Universe in its infancy was pieced together from data collected over several years by the Wilkinson Microwave Anisotropy Probe (WMAP). The different colours reveal the 13.7-billion-year-old temperature fluctuations that correspond to the seeds from which the galaxies grew.
NASA
As the Universe expanded, the denser areas within it expanded more slowly than others because of their increased gravity. By the time these areas were twice as dense as their surroundings, the matter within them was sufficiently cool and dense to collapse under their own gravity and form the first stars and cores of new galaxies.
The rest, as they say, is history. Across the cosmos, countless suns began to switch on and the fill the Universe with light. For billions of years, generations of stars lived and died until, 9 billion years after it all began, in an unremarkable piece of space known as the Orion Spur off the Perseus Arm of a galaxy called the Milky Way, a star was born that became known as the Sun. This is the story of how our solar system has its ultimate origin in those dense areas of space that appeared in the first moments of our Universe’s life. But what is the origin of those tiny fluctuations in density that we see in the CMB?
This is perhaps the most remarkable piece of physics of all. The most popular current model for the very very early Universe is known as inflation. The idea is that around 10– 36 seconds after the Big Bang, the Universe went through an astonishingly rapid phase of expansion in which it increased in volume by a factor of around 1078! In less scientific notation, that’s a million million million million million millionths of a second after the Big Bang, and an increase in volume by a factor of million billion billion billion billion billion billion billion billion billion. This was all over by 10–32 seconds or so. Before inflation, the part of the Universe we now observe, all the hundreds of billions of galaxies in our night sky, would have been far, far smaller than a single subatomic particle. At these minute distance scales, quantum mechanics reigns supreme, and tiny quantum fluctuations before inflation would have been magnified by the rapid expansion to form the denser regions we observe in the Cosmic Microwave Background spectrum. If inflationary theory is correct, the CMB is therefore a window onto a time in the life of the Universe far earlier than 400,000 years after the Big Bang. We are seeing the imprint of events that happened in the truly mind-blowing first million million million million million millionths of a second after it all began. I find this the most astonishing idea in all of science. From a vantage point of 13.7 billion years, little beings like you and me scurrying around on the surface of a rock on the edge of one of the galaxies are able to understand the evolution of the Universe and speculate intelligently about the very beginning of time itself, just by decoding the messages carried to us across the cosmos on beams of light. The power of science is quite genuinely daunting, the richness of its stories unparalleled, the cosmos it reveals, beautiful beyond imagination.
There is one last twist to this story. Throughout our journey, light has been the messenger, carrying stories of far-flung places and the distant past to our shores. But there is evidence from one of the ancient sites on our home planet that light may have played a far more active role in our history than mere muse
The Burgess Shale is one of the most important and exciting fossil sites in the world, where a staggering amount of diverse animals are to be found, dating back over 500 million years.
FIRST SIGHT
Hidden in the high Rocky Mountains in British Columbia, Canada, is one of the most important and evocative scientific sites on Earth, and it’s where the story of light and our lives begins. Around 505 million years ago, when this whole area lay deep beneath the surface of a