Dark Matter: Why It Hides from Us Behind the Atmosphere ⚡ экспресс
Ultralight dark matter with a special type of interaction can be screened by the atmosphere, hampering ground-based experiments. But quantum clocks on the ISS pick up the oscillations of fundamental constants it causes. When its wavelength is less than the Earth's radius (for masses above 10⁻¹⁰ eV), a dipole cloud emerges, modulating the signal—this provides cross-validation. Optical clocks can set record limits, while nuclear clocks can explore parameter regions inaccessible from Earth.
Since Vera Rubin first convincingly showed that galaxies are surrounded by invisible matter, the quest to understand the nature of dark matter has remained one of physics' greatest challenges. New research suggests that ultralight dark matter could be screened by Earth's atmosphere if it has a special 'quadratic' interaction with Standard Model particles (like a double handshake). Near our planet, the density of these particles changes, and the atmosphere acts as a shield, limiting the signal in ground-based laboratories.
At the orbital altitude of the International Space Station, the atmosphere is gone, and the 'rain' falls unimpeded. Ultra-precise optical clocks could pick up shifts in fundamental constants caused by passing dark matter. If the particles' de Broglie wavelength is smaller than Earth's radius, a dipole pattern forms around the planet, which oscillates as the station moves. This creates a distinctive signal that's hard to mistake for noise.
Orbital clocks might place the tightest constraints yet on the properties of ultralight dark matter, and future nuclear clocks will extend the search even further.
🎯 If dark matter interacted strongly with the atmosphere, we'd feel it as extra air pressure — but it's vanishingly small compared to normal atmospheric pressure.