wires. When they reach the filament in the light bulb, they drop into a low-energy state and when they do that they release a photon. Trillions of photons stream out of those bulbs every second. They bounce around the room changing slightly as they come into objects with different colours and properties until they bounce into our eyes and bind to a new electron in a photoreceptor that sends a signal to our brain.â
Danyl looked at the light. He said, âHuh.â He felt a little ashamed. All his life heâd been seeing things, yet he had no idea how seeing worked.
âAt the beginning of the twentieth century, physicists wondered about the strength of the interaction between electrons and photons. Itâs not difficult to calculate.â She wrote an equation on the condensation of the window with her fingertip. âItâs the charge of the proton divided by the quantum of action multiplied by the speed of light in a vacuum. When we solve this equation we get this number, which physicists call the fine structure constant, which is about 1/137. Now, normally when you carry out equations in physics, you end up with a number and a unit. The speed of light gives you a distance that you can travel over time, and you can measure that in miles, or kilometres, or whatever you want. The photon charge gives you the strength of the charge, and physicists like to measure that using a unit called coulombs. But when you calculate the strength of the electromagnetic interaction, something interesting happens. You get this numberââshe pointed to 1/137ââbut no unit. No matter how you measure the other variables in the equation, it will always return this specific number. Itâs a dimensionless constant hidden away in the deep structure of the universe. Now, hereâs where it gets strange.â
Danyl nodded and said, âHuhâ again.
âWhere did this number come from?â Ann spread her fingers. âNo one knows. Einstein wondered if God had any choice in the way He designed the universe. Could He have built it differently, or is this universe in which we exist the only viable option? Of course, there is no God. Thatâs a false metaphysical premise. But it turns out that if the fine structure constant was slightly larger than it is, there would be no carbon in our universe and probably no intelligent life. If it was smaller, you wouldnât get star formation and the universe would be a cold, dead, lifeless place. So this numberââshe pointed againââmust have this exact value, because if it didnât we wouldnât be able to observe it. Philosophers call this âthe fine-tuning problemâ: why does the universe seem like itâs been designed to allow the existence of intelligent life?â
Danyl asked, âWhatâs the answer?â
âNo one knows. Thatâs what Sophus was working on before he got distracted studying scraps of paper he found in the gutters of Te Aro. He wanted to solve the tuning problem by enumerating the fine structure constant. If he could relate it to the number of dimensions in the universe, or to some significant mathematical value like pi or the infinite sum, then he could say: âThereâs no fine-tuning problem because the electromagnetic interaction must have this value. Itâs all part of a logical framework and not an arbitrary number that just happens to allow the existence of complex life.â Sadly, there are plenty of lunatics out there who try to link the fine structure constant to codes in the Bible, or the secrets of the Illuminati. That must be how whoever is behind these disappearances snared Sophus.â
âWhat do we do next?â
âWe search that alleyway,â Ann replied. âFirst thing tomorrow, after weâve slept. And if we donât find anything, we need to track down one of these blue envelopes and see whatâs inside it.â
âDo you