XENON’s experimental triumph: no dark matter, but the best “null result” in history
Searching for dark matter, the XENON collaboration found absolutely nothing out of the ordinary. Here’s why that’s an extraordinary feat.
More than 100 years ago, the foundations of physics were thrown into utter chaos by an experiment that measured absolutely nothing at all. Knowing that the Earth moved through space as it rotated on its axis and orbited the Sun, scientists sent beams of light in two different directions — one along the Earth’s direction of motion, and one perpendicular to it — and then reflected them back to their starting point, recombining them upon arrival. Whatever shift the Earth’s motion would have caused within that light would be imprinted on the recombined signal, allowing us to determine what the true “rest frame” of the Universe was.
And yet, there was absolutely no shift observed at all. The Michelson-Morley experiment, despite achieving a “null result,” would wind up transforming our understanding of motion within the Universe, leading to the Lorentz transformations and special relativity thereafter. Only by achieving such a high-quality, high-precision result could we learn what the Universe was and wasn’t doing.
