“Detecting the first gravitational wave event has changed the world.” Most breakthroughs in physics are too arcane to attract headlines, but the media thought that news of gravitational waves ought to rouse public attention.
Cosmology and subatomic physics transport us from the solidity of daily experience to the weird territory of the infinitely vast and unimaginably minute, a dreamy encounter that is stranger than fiction. I doubt that biologists have much advantage over non-scientists for apprehending modern physics. For a subject to be “real” in our experience we need to use our five senses: we have to see or hear or touch or smell and taste. Of course, we have a wide range of instruments at our disposal, but they are aids to engage the organic and inorganic with our sense organs. Physicists use instruments too, but the door to a deep understanding of their world, and the rationale of their experiments, hinges on mathematical symbolism and equations, and when we step inside it seems strange and ethereal.
I don’t normally even drag my feet to the door of modern physics, although news of gravitational waves makes this a ripe time for struggling to understand what the fuss is about, and why it matters for the scientific legacy of Albert Einstein. In drafting this post I am stepping up to his advice: “If you can’t explain it, you don’t understand it well enough.” [Readers who are physicists please correct factual errors!]
I imagine Isaac Newton watching an apple fall from his tree at Woolsthorpe Manor. That set him thinking about gravity, or so the story goes. He reckoned there was a “force” of gravity responsible for objects falling and attracting each other, including the Earth spinning around the sun and the tides ebbing and flowing. But this “force” was mysterious, for how could it act between stars, planets and moons across the void of space?
Roll forward two centuries to when Albert’s father was an engineer installing electrical power in Italy. The young Einstein was musing about the nature of electromagnetic fields, which obviously have a fundamentally different character to classical Newtonian forces: they can bend and vibrate. Idle thoughts sometimes ignite the fuel of genius more readily than dry lectures and labor in the library. After enrolling as a student in Zurich, he gathered his ideas to formulate the equation E=mc2 and three famous papers announcing relativity theory. The year was 1905, his annus mirabilis.
Despite the sudden acclaim, he was uneasy that Newton’s universal “force” of gravity didn’t fit comfortably with the paradigm of a space-time continuum, although exactly what troubled him I cannot explain because that is one of the black holes in my understanding! But it was so important that he devoted the next decade to the problem, eventually yielding as his Theory of General Relativity. It was a masterpiece of science as sublime as the highest art, as King Lear or Guernica or the Messiah. Casting aside a theory handed down from the old father of physics, he realized that space is not distinct from the “material” fabric of the universe, and it is curvy and bendy. To quote Carlo Rovelli (Seven Brief Lessons on Physics, 2014), “the gravitational field is not diffused through space; the gravitational field is that space itself.” It is a concept so simple and yet counter-intuitive that it took a breathtaking stroke of imagination.
The world spins around the sun not from the action of Newtonian forces, but more like a track cyclist racing in a velodrome, round and round it goes on the contours of the curved walls, and the same curving of space causes planets to evolve and things to fall. His theories may have originated in thought experiments but they were confirmed by equations to predict exactly how matter curves space, the motions of the planets, why objects fall, why light is bent by the mass of the sun, and why time passes very slightly faster at the top of a skyscraper than at its base. This revolution brought us the Big Bang and Black Holes too.
Einstein predicted the existence of gravitational waves rolling through space-time, but there was only indirect evidence. The recent news frenzy was triggered by confirmation of his last unproven prediction after a decade of endeavor. Incredibly sensitive optical instruments were used to detect a wobble in the gravitational field, which was caused by a huge release of energy from the fusion of two Black Holes immensely far off in time and distance. My grasp of these concepts is as bottomless as a Black Hole, and I grasp for an easy analogy and have to discard the earlier one.
A gravitational field is more like a trampoline than a velodrome. I imagine standing on a trampoline to deform the warp and weft of the fabric, and making a ball (read a planet) roll towards me. When I jump up and down on it I generate ripples that gradually fade towards the edges of the trampoline, like the wobbling gravitational field detected last September.
A practical mind will ask if the discovery of gravitational waves has any use. Wouldn’t research funds be better used on something less “theoretical?” It’s a tempting question for biologists who mostly work towards a definite practical goals, like a cure for cancer or conservation of species. Perhaps Newton’s peers wondered why he bothered playing with prisms or Galileo made telescopes. This is the familiar debate between basic science versus applied science, and only time will tell whether gravitational waves ruffle newspapers headlines again, but hopefully they will unfold enigmatic Dark Energy, Dark Matter and other mysteries that will enrich us in some ways.
For sure, physics is not running out of big projects. And perhaps it lights a path for biology too, which still rests on the familiar bedrock of matter and energy. We don’t have an equivalent of the Einsteinian vision, and are largely resistant to deep and mysterious theories, like morphic fields and the Gaia hypothesis. We generally have our feet firmly planted in loam, and perhaps because living nature is so much more complicated we have to be more simple-minded. Maybe it is because physics is more alien and unapproachable, rarely threatening our sensibilities, that there are contrasting attitudes to the twin cornerstones of science, Einstein’s Relativity and Darwin’s Evolution. While the public wholeheartedly receives the former with awe, fifty per cent of the American public repudiates the latter. I envy the privilege of physics and groan at the politics of biology!
Posted from New Zealand
Next Post: Frozen Egg Perks as Policy