In the 1930s, Fritz Zwicky noticed that galaxies move as if tugged by an invisible weight. Later, Vera Rubin proved that stars on the outskirts spin too fast: they are held together by dark matter. But catching its particles has proven impossible: they pass through everything like ghosts.
Now physicists have designed a trap from sponge-like porous crystals. If a dark matter particle collides with such a sponge, a twisted sound wave, a tiny magnetic vortex, is born inside. This "whisper" can be heard using an ultra-sensitive sensor coated right onto the crystal.
The biggest surprise: the sponge's sensitivity barely depends on its composition. You can change the chemical ingredients, add rare dopants — the sensitivity doesn't drop. This makes the detector flexible. Moreover, the twisted waves here resemble the symmetry-breaking process after the Big Bang. Since the Standard Model is silent about dark matter, a successful trap like this would open the door to new physics.
Porous sponge crystals are already at work in practice: they are used to capture carbon dioxide from the air and store hydrogen in the cars of the future.