Earth as a Lens for Searching Dark Matter ⚡ экспресс
Earth's gravitational field can act as a lens, focusing dark matter particles (axion-like particles, ALPs) into a cosmic focal point. By aiming a laser beam there, we can stimulate their decay and detect the return signal. Simulations assuming ALP speeds of 520 km/s (from the S1 stellar stream) place the focus at about 9.6 billion meters (~25 lunar distances), with a sensitivity of g/M ~ 10⁻²² GeV⁻¹ for a source at 8 kpc. This lays the groundwork for future space telescopes capable of detecting dark matter beyond the Milky Way.
Dark matter is the invisible backbone of the universe. Vera Rubin proved its existence by the motion of stars, yet the particles themselves have never been captured. A new method turns Earth into a giant gravitational lens: a massive body, as shown by Einstein, curves spacetime and focuses passing dark matter particles into a point beyond Pluto's orbit. That spot is about the size of a football field.
A powerful laser is aimed at the focus. If dark matter consists of axions – ultralight particles outside the Standard Model – the beam makes them momentarily turn into photons and reflect light back. Like a match igniting invisible gunpowder, the laser triggers a flash that can be registered.
Calculations show: at speeds around 520 km/s, the focus lies 9–14 billion meters away. The sensitivity is such that a signal can be picked up even from the opposite edge of the Galaxy. This approach paves the way for a space observatory to directly detect dark matter.
🎯 The distance to Earth's gravitational focus is roughly the distance light travels in half a minute — farther than Pluto, but still within our solar system.