Cosmological discoveries over the past century have completely changed our picture of our place in the universe. New observations have a realistic chance of probing nature on heretofore unimaginable scales, and as a result are changing the nature of fundamental science. Perhaps no other domain of science has an equal capacity to completely change our perspective of the world in which we live.
Deep Dive into The Big Bang, Modern Cosmology and the Fate of the Universe: Impacts upon Culture.
Cosmological discoveries over the past century have completely changed our picture of our place in the universe. New observations have a realistic chance of probing nature on heretofore unimaginable scales, and as a result are changing the nature of fundamental science. Perhaps no other domain of science has an equal capacity to completely change our perspective of the world in which we live.
Ever since humans have had the capacity to wonder, they have been inspired by the night sky to wonder about questions such as: Where did we come from?, or, Are we Alone?, or How will the Universe end? These questions and others form the very basis of much of human culture, beginning with myths and religion, and moving, over the past 400 years into the domain of modern science.
If you stare up at the night sky from a dark place in the country, it is beautiful, to be sure. However, we have realized over the past quarter century that the beauty we see is only the tip of a vast cosmic iceberg. The really important stuff in the universe, at least the stuff that governed the formation of all cosmic structures and that will determine the ultimate fate of the universe itself, lies in the stuff we cannot see. Over 95 % of the energy of the universe is invisible to telescopes, in the form of dark matter, which dominates the mass of essentially all galaxies, and even stranger, dark energy, which seems to permeate empty space, and accounts for almost 70 % of the energy in the universe. Determining the nature of these two mysteries forms of mass and energy represent perhaps the greatest challenges to modern physics and cosmology.
As we ponder esoterica like dark matter and dark energy it is easy to lose sight of how much our picture of the universe has changed in even the span of a single human lifetime. Eighty five years ago our universe consisted of a single galaxy, our Milky Way. Now we know there are over 400 billion galaxies in the observable universe! More remarkable still, almost all people now take for granted the fact that our universe had a beginning which occurred a finite time ago. Literate people understand that beginning to have occurred in the Big Bang Explosion, some 13.7 billion years ago. (Alas, in the United States some 50 % of the US public still think the Universe is less than 10,000 years old, but I don’t consider these people literate.) But it is worth remembering that in 1916, after he had made his greatest theoretical discovery in developing the General Theory of Relativity, Albert Einstein, like essentially the entire scientific community, still thought we lived in a static eternal, and largely empty universe. The fact that General Relativity does not allow a static solution with an extended mass distribution led Einstein to introduce his now famous Cosmological Constant as a fudge factor that he hoped might make his theory consistent with observations. After Edwin Hubble unambiguously demonstrated a decade or so later that our universe is expanding, obviating the need Fate of the Universe 11 for a cosmological constant, Einstein called introducing it his biggest blunder. More important than changing Einstein’s views, an expanding universe implies that earlier on it was smaller, and earlier still smaller, until ultimately everything was together at a single point.
The Big Bang changed everything. So much so that the notion that the Universe had a beginning is now taken for granted across almost all cultures. Interestingly the Big Bang has been seen on the one hand as a validation of religious notions of creation, and on the other as a direct challenge. Most modern efforts to rid public school classes of the basis of modern biology, namely evolution, also try and remove discussions of the Big Bang.
It was not always that way. When the Belgian priest and physicist Georges Lematre first demonstrated mathematically, in 1931-shortly after Hubble’s discovery-that the equations of general relativity actually required a big bang-he was hailed by many, including Pope Pius XII, who 20 years later claimed that Lematre had proved Genesis.
Incidentally, Lematre himself felt quite differently. He initially inserted, then ultimately removed, a paragraph in the draft of his 1931 paper remarking on the possible theological consequences of his discovery. In the end, he said,“As far as I can see, such a theory remains entirely outside of any metaphysical or religious question.”
The Big Bang is not a metaphysical theory, but a scientific one: namely one that derives from equations that have been measured to describe the universe, and that makes predictions that one can test. Nevertheless, it is, to me, a remarkable example of how science can affect culture. The very notion that the Universe had a beginning, whether or not that beginning is shrouded in mystery, is an essential part of the gestalt of modern life. We should celebrate that.
In the past decade there has been another discovery that will, I believe, ultimately have an equal impact upon our picture of our place in the cosmos, not because it affects our understanding of the past, but because it affects our picture of the future. The discovery of dark energy has also changed everything about cosmology. Before I explain why, I should quickly summarize the observational steps that inexorably led us to the strange conclusion that empty space contains mo
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