The Inside of the Pearl
Katie Mack’s article in the Washington Post this Sunday focused on her reaction to the news that gravitational waves have been found to constantly writhe and contort their way through the universe. That put me in mind of this article that I originally wrote for the Mensa Bulletin and later made its way into the MIT physics newsletter. The music of the spheres is, indeed, a joyful noise.
Has your eye ever been captured by the beauty of a pearl, the milky sheen with just a hint—almost imagined—of blush? That blush makes pearls seem to be living things. When I first learned what a pearl was and how it was made, I thought it was a grand mystery. The thought of something so pure and perfect starting with an irritating grain of sand, growing with the sticky mucus of an ugly bivalve seemed to be miraculous to the point of supernatural. Pearls became my fairyland of choice.
On rainy days, when Minnesota skies was filled with gray and drear, I would steal away to my parent’s bedroom. There I would silently remove my mother’s pearls from the drawer where they were kept, carefully wrapped in tissue and velvet. I never touched them; instead, I would stare intently at the strand’s large center pearl. I imagined myself growing small and smaller, diving through the layers of nacre to the center of that pearl. There I would live in my own tiny world. In my mind, when I sat on the center grain of sand which was my pearly home and looked at the curved sky of solid, transparent white, to that curved shell of pearly heaven, my world always seemed very large to me, even though I was a spec and my universe only a pearl.
When I study physics, I feel like I am back inside that pearl. Physicists understand what it is like to be very small and very large all at the same time. The works of Jastrow, Sagan and Hawking have always been part of my library.
That is why I have been following, with constant wonder, the gradual challenge and acceptance and confirmation of the concept of dark energy. It also affirms what I have always felt about Albert Einstein—he had the ability to be right without being able to prove that he was, perhaps without knowing he was, or why such rightness had to be. My hunches might live in my gut (not an unknowledgeable place) buy Einstein’s were an electric spark connecting the axion of one neuron with the dendrites of another and bringing a glow of surety to one miniscule synapse. Yes, he knew.
On the matter of Dark Energy, Einstein was right in two ways, first his cosmological constant (which he later repudiated, like any good scientist, for lack of confirming empirical data) does work to explain the presence of Dark Energy. Second, and most important, he was right in his belief that the unifying aspect of all theories would be in gravity. The child in me knows this truth, but I must count on the theoreticians to give me the hard cold facts. Thankfully, they are working at that with technology Einstein would have loved.
On Thursday, February 11, 2016, the scientists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) called a press conference to announce their discovery of gravitational waves. These waves are what bend space and time. The ripples that LIGO has detected are probably the result of two black holes running into each other. This is science for the sake of science. Knowledge for the sake of knowledge. It will change how we see the universe. It may or may not be helpful in an (as yet unknown) way, but it opens a large and clear window on cosmology. It also plays another counterpoint to the music of the spheres.
But gravitational waves are produced by gravity and gravity implies mass—mass and distance specifically. Distance comes hand in hand with time and all of this is quantifiable, which means that there are numbers here that stretch infinitely in both directions away from the one number that is not a number, the zero that exists on only one spot on the number line. Oh, it functions as a place holder everywhere, but stands on its own in only that one spot which separates positive from negative integers. There is no such thing as positive or negative “0.”
Cosmic Microwave Background (CMB) has provided both answers and questions to cosmologists. Microwave energy, measured through an alphabet soup of new devices, is a remnant of the Big Bang. The fluctuation of the CMB shows the kind of hot and cold spots scientists expect from the results of the Big Bang. An explosion in the relative vacuum of space will expand in a sphere, but debris—even primordial atomic debris—will scatter in clumps, braids and strands. Cosmic Microwave Background reflects this dispersal as we believe it may have looked from about 400,000 years after the Big Bang.
The alternating compression and expansion of microwaves (compressed by gravity, expanded by radiation) produce both a sound wave and heat. If you want to illustrate this principle in a highly simplified way, take a thick rubber band, listen to it and you will hear nothing. Touch it to your upper lip and you will feel nothing but the ambient temperature of the room. Now, rapidly expand and release it several times. Listen to the low thumping sound it makes. On one of the last expansions, touch the rubber band to your upper lip. It will be warm. The CMB reacts in the same way. While the heat signature of the microwave background is too delicate to be detected, that rhythmic throb of the microwave expansion and contraction is what cosmologists are listening for.
There is also ample evidence to confirm that what you and I would call mass, makes up only about 5% of the universe. Another 30 % has been identified as dark matter—physically there, but unseen. That leaves a whooping 65% currently supposed to be dark energy. Dark energy (oh, would Einstein love this!) apparently is antigravity.
While doing a summer institute at the Harvard Center for Astrophysics I had the pleasure of hearing Dr. Margaret J. Geller talk about her study of galaxies. She is the astrophysicist who proved that galaxies cluster on what appear to be the surface of cosmological bubbles. Just as soap bubbles coalesce along the rim of connected bubbles, sharing some space side by side, while leaving huge arcs of the bubble untouched, so galaxies form in our universe. These are not real bubbles of course, but the bubble analogy explains the structure.
Bubbles, planets, and stars, like my pearls, are all spheres. And there is a very good reason. Everything that exists in the physical world, no matter how large or small, has mass. Everything with mass, has a gravitational force. Gravity exerts a force that is directly proportional to the size of its mass and inversely proportional to the square of the distance between it and any other mass. This force is exerted equally in every direction from the mass itself. Because of this, objects left at the mercy of their own gravitational fields, tend to form themselves into spheres. Stars are very large spheres. Atoms are very small ones.
Now let’s think about Dr. Geller’s galaxies, forming, as they seem, on the surface of bubbles, and all of that dark energy that seems to be at work in our universe.
Dark energy is antigravity, pushing the mass of the universe away from itself at a rate that creates a flat, not a pulsating universe. If that is so, would it not then behave as gravity does, only in reverse? Would dark energy not have spewed from the Big Bang in the same haphazard and pervasive way as did nascent matter? Would central cores of dark energy not exert a force equally in all directions away from itself? Would dark energy not form bubbles of antigravity, with the world of matter occupying the skin of those bubbles where dark energy has stretched itself too thin to counteract the positive gravitation of the world of physical mass? The logic as well as the mathematics fit together neatly.
The awesome combination of matter, dark matter and dark energy form a delicate equation that turns scientists into philosophers. It is a pearl of perfection.
Taking the big picture helps me keep the faith.
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