Saturday, January 18, 2014

Scientific Cosmology: The Dark Gardens of Space

            Professor Ted Bunn, a physics professor at the University of Richmond, recently came to Boston to speak to us about the latest thinking on the nature of the physical universe and related questions. The program took place in Emmanuel Church in Boston, and since we needed to exercise our brains, as all the health latest advisories say we should -- though why this entails playing brain-exercise games on the Internet I'm not sure I understand -- we trotted like good seekers of knowledge down to the church on Sunday, arriving just as the church's coffee hour was turning into the science presentation.

            Professor Ted did a great job of pointing out that most of the universe, according to the latest scientific thinking, consists of either dark matter, or dark energy. About 96 percent in total. That leaves 4 percent for the plain old ordinary matter and energy, or as he put it, "atoms." So only 4 percent of everything there is consists of anything we can know anything about; and the names given to the other components, "dark" matter and "dark" energy are not encouraging to the idea that we will come to "know" these ingredients any time soon. We are very much "left in the dark" about the contents of the universe.

            Why is this 96 to 4 percent ratio not entirely comforting? What else are we potentially missing out there? That's a lot of weight in the "unknown" or even "unknowable" category when you try to address one of the deepest of the traditional cosmological questions: What is the nature of the universe?

            So currently, it seems to me, if you wish to go on believing that regiments of angels can dance on the head of a pin, or that a near infinity of "multiverse" universes are dwelling unseen among us, there is plenty of space in our largely "dark" universe to carry on that order of speculation.

            The 28 percent, or so, that is currently billed to the dark matter column is necessitated by astrophysicists to account for the gravitational effect required by the current theories to explain why the universe is not pulling apart any faster than it is.

            For, yes, everything in the "universe" -- a term I take here to mean everything we know by our senses to exist or have observed by some instrument -- is moving away from everything else in the universe, according to the now widely accepted expanding universe theory. This is possible because... well, this is what our instruments and our equations are telling us.
           And the question raised in my mind by this current scientific tenet is: what is this universe expanding into?

            Second question (or observation): How lonely is that?

            An expanding universe raises the common sense consideration, not discussed in the professor's talk, of how all those other sentient races out there with their presumably advanced civilizations are going to contact us? Distance is a barrier to travel; even to communication in the Einsteinian universe where the speed of light is a constant. Fact is, so the current thinking tells us, we're just getting farther apart.

            From some "imaginative" points of view of course, distance doesn't matter. But we call those points of view "science fiction."

            Worse, our expanding universe would be running away from itself at a much faster rate if something -- the professor called it "dark matter" -- did not exist to add its "mass" to what we can observe in the universe (call it "atoms") to provide the gravitational brake on universal expansion. That is to say, dark matter is a hypothesis.

            But why do rely so much on "gravity," this child of the Newtonian universe whose other lineaments we have left behind so long ago, to hold our picture of the universe together? Is there something else out there -- some principal, or force, or law -- we just don't know about yet?

            Doesn't it make as much sense to believe that the universe is riding on the back of an enormous tortoise? Maybe we just haven't figured out how to "see" the tortoise.

            I am sorry to confess that I make even less sense out of "dark energy," that indefinable something current scientific thinking posits to fill some 68 percent of the universe. Dark means we can't observe it; our instruments can't. So it's a hypothesis.

            So, the Wik tells us that "in physical cosmology" dark energy is a hypothetical form of energy that permeates all of space and accelerates the expansion of the universe. That's "dark," all right. By comparison, dark energy turns that archvillain The Lord of the Rings into a jumped-up schoolyard bully. Despite its domination of the universe, the theory goes, it's not much of a force within our own solar system, weighing a mere 6 tones in total, about the size of one our neighborhood SUVs. However, according to current thinking, dark energy dominates "the mass-energy" of the universe because it spreads uniformly throughout space. Remember, there is a lot more "space" than there are solar systems.

            The universe is, measurably, expanding, this reasoning goes. Some force must drive it; must overpower the universal gravity that holds us together. Since we know nothing about this force, except there must be a lot of it, we create another hypothesis: "dark energy."

            And so, since this picture of the universe gives me almost nothing with which to address the basic cosmological questions:

            What is the nature of the universe? (or "the world"? or "life"?)

            How did the universe begin? If it began in "time," what was there before the universe?

            Is the universe finite? Infinite? If it is finite, what exists outside the universe? If it is "expanding," what is it expanding into?

            And why is there being rather than nothingness?  Or, in another common formulation, why do we exist? ...

              .... I turn, as I have done before, to the poem by Walt Whitman that best sums up for me the difference between what science can deliver to benefit the always restless human mind and what the human soul requires:

                        When I heard the learn’d astronomer

      When I heard the learn’d astronomer,

      When the proofs, the figures, were ranged in columns before me,

      When I was shown the charts and diagrams, to add, divide, and measure them,

      When I sitting heard the astronomer where he lectured with much applause in the lecture-room,

      How soon unaccountable I became tired and sick,

      Till rising and gliding out I wander’d off by myself,

      In the mystical moist night-air, and from time to time,

      Look’d up in perfect silence at the stars.