As you might have noticed by now, I love writing about science. And about physics especially, even though I can barely do basic math. Last year, I enjoyed writing a post called The Coolest Discovery You’ve Never Heard Of. It’s about Bell’s Theorem, which is such a fascinating subject that I considered writing a non-fiction book about it. (Wisely, I gave up.) Henry Stapp called it “the most profound discovery of science,” and I tried to explain it (to the best of my very limited understanding) using pairs of black or white socks and cardboard boxes.
So, you can imagine my excitement when I stumbled upon this Youtube video from Nova explaining how, in 2018, physicists figured out a way to close one of the potential loopholes that might invalidate the previous, successful tests of Bell’s Theorem. Namely, that you cannot absolutely positively rule-out the existence of some hidden (local) variable that is secretly affecting which tests Alice and Bob use in the experiment (sock length or sock color, in my analogy). An international team of physicists and astronomers gathered at an observatory on the Canary Islands and used the light from two distant quasars as a kind of light-based coin-flip for Bob and Alice, thus ruling out any kind of weird, as-yet-unknown force that could flummox the test.
And—lo and behold—it worked. Bell’s Theorem was confirmed. Again.
Of course, there is still one outstanding loophole in the test, one which might never be closed. It’s the concept of superdeterminism, the idea that everything in the experiment above (everything in the entire universe, actually), including Alice’s and Bob’s choice of tests, is pre-determined. But that possibility—with its implied invalidation of human free will—is just too depressing to entertain, don’t you think? I believe the universe has a much more interesting role for us.
The video is embedded above. (You can ignore the title—it’s really about the cosmic Bell test.) Enjoy!
