What Heinrich Rudolf Hertz taught us about nothingness
Heinrich Rudolf Hertz, who was honored Wednesday on his 155th birthday, helped explain how even nothing at all can be something.
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But Einstein did. By imagining light not as a wave, but as a particle carrying discrete packets of energy, which he called "quanta," Einstein found that he could predict how certain frequencies of light would electrify certain metals. Einstein's explanation of the photoelectric effect won him the Nobel Prize in physic in 1921, and helped usher in the era of quantum physics.Skip to next paragraph
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Eoin works on the Christian Science Monitor's online editorial team. His interests include science, technology, and digital media and its effects on people.
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So now we understand light, and all electromagnetic radiation, as having a dual role of both wave and particle. Electromagnetic radiation, including light, travels as a wave, but arrives as a particle, and there's no need to invoke any mysterious aethers.
Or is there? Einstein himself continued to use the word, particularly when attempting to describe how gravity acted on distant objects. And the quantum mechanical conception of vacuums are anything but empty: they contain ephemeral particles that pop in and out of existence, and even fleeting electromagnetic waves. Once you get to a very small scale, the universe starts too look a little more like Aristotle and the other plenists imagined it.
Take a look at this Scale of the Universe animation, created by a pair of extremely precocious 14-year-old twins named Cary and Michael Huang earlier this month. Zoom in, past the penny, past the matchstick, past the paramecium and the DNA molecule. Keep zooming. Go past the gamma ray and the proton and the neutron. Go past the quarks and the neutrinos. Eventually, you'll get to a whole lot of nothing.
In fact, most of what we take to be solid matter actually consists of empty space. If you imagine an atom the size of a cathedral, its nucleus would be roughly the size of a fly. Thanks to electromagnetism, in this case the tendency for electrons to repel each other, everything doesn't collapse in on itself. You may think that you are sitting in a chair right now, but you are actually hovering above it at a distance of one angstrom, about 250 millionths of an inch. Neither your electric field nor that of the chair wants to get any closer.
Anyway, keep zooming in. Eventually, you'll get to the Planck Length, which is what physicists say is the smallest unit of measurement in the universe. At anything smaller than this distance, it would be impossible to tell the difference between two locations.
At this scale, physics is really weird. "Virtual" particles are flashing in and out of existence at extremely high energies, warping space and time into a quantum "foam," or so one theory goes. One-dimensional strings, according to another theory, vibrate in eleven dimensions, forging and maintaining the very fabric of our reality.
Now zoom all the way out. All the way, past the planets, galaxies, and nebulae, until you get to our entire, expanding, universe. What is the universe expanding into? Nothing at all, according to the best current cosmological models. What was there before the universe? Was that nothing too?
The ancient Greeks were fond of another phrase about nothingness: It comes to us via the Latin expression "Ex nihilo nihil fit," or "nothing comes from nothing." They believed that the gods fashioned the universe out of a primeval matter, which they called "chaos."
Today, as cosmologists try to explain how our universe sprang from nothing, it's worth remembering that, in science, nothing is not what it seems.