Turns out creating light isn’t such a divine act after all. Not in the sense of powering on a lightbulb or firing up a star or discharging some static electricity. No, creating light in the Genesis “let there be light” sense. Light from nothing at all. This is, essentially, the accomplishment of Chris Wilson and pals at Gothenburg’s Chalmers University of Technology, as detailed in a new piece in Nature. Take the most exquisite nothing-nothingness in the whole wide universe and create light from it.
As an idea, called the dynamic Casimir effect, this is actually about 40 years old. It stems from one of my own personal favorite weirdnesses about the universe: that there is no such thing as “empty.” Like, if you remove absolutely everything from a region of space — every atom, every particle, all of it — it will still bubble with “virtual” particles that result from quantum fluctuations. The uncertainty principle applies even in a vacuum. That is, way oversimplified, a true vacuum (zero energy) is too certain for quantum physics (for the universe). Thus, pairs of virtual particles are created constantly. They exist for an extremely short time and pop back out of existence.
This is manifested in the Casimir effect. If you take two mirrors and place them side by side in a vacuum, they will pull toward each other. This happens because there’s a limited amount of space between them for virtual particles to come into existence, so more are popping out of space outside of the mirrors. This results in an increase in pressure outside the mirrors, and they pull toward each other.
With the dynamic Casimir effect, we’re actually harnessing those virtual particles (photons, actually) and turning them into light. It’s not easy. Four decades ago, the idea of speeding a mirror up to near light speed and sending it through a vacuum came about as a way of turning virtual photons in real photons and, thus, light.
Of course. we can’t very well fire a mirror at light speed through a vacuum. So Wilson and co. devised an alternate way involving changing the length of the pathway an electron follows in a circuit very, very quickly, such that it nears the speed of light. Well, it worked. The researchers made out with real light from nothing.
See also: dark energy, the mysterious stuff that’s supposed to make up most of the energy in the universe. It’s thought to be a result of this sort of virtual background energy, the energy of the vacuum. So think on that for a while — it’s easier, more natural, for the universe to have stuff in it than it is for it to be empty.
- Dark Energy Is Still, Uh, Whatever the Hell Dark Energy Is
- Yes, the Universe Is Hurling Us Out Into Darkness
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