Cosmic Wake Exposes Hidden Motions ⚡ экспресс
The moving lens effect is a secondary anisotropy of the cosmic microwave background caused by the transverse motion of gravitational potentials. A spectral estimator in Fourier space was developed that preserves the scale dependence of the signal, and applied to ACT DR6 data and samples of luminous red galaxies from the DESI Legacy surveys. On foreground-suppressed maps, a non-zero cross-correlation signal was hinted at: b_ML = 1.24 ± 0.26 (4.8σ) for the extended sample and 0.93 ± 0.25 (3.7σ) for the primary one, consistent with the halo model prediction. Separating the scales of reconstructed velocities and the cross-correlation was critical for controlling systematics. Residual foreground contamination, estimated via simulations and multi-frequency analysis, is significantly smaller than the signal. The results are robust to different processing choices, and curl mode tests do not exceed 2σ. This detection opens up transverse velocities as a new cosmological observable, and combined with the kinematic Sunyaev-Zel'dovich effect enables reconstruction of the universe's 3D velocity field, creating a new tool for studying structure growth and gravity on large scales.
Moving clumps of galaxies and invisible dark matter create wakes in the afterglow of the Big Bang, like boats stirring a pond. This wake—the moving lens effect—is so subtle it shifts the light’s temperature by only a few millionths of a degree: comparable to detecting a candle’s heat from across a continent.
Now, combining two telescope surveys, astronomers have detected this sideways motion for the first time. Until now, we could only see how matter moves toward or away from us.
Pair this with the Sunyaev-Zel'dovich effect, which tracks gas motion, and a full 3D velocity map emerges. Such maps will test the standard model of cosmic expansion and trace the hidden currents shaping our universe.
🎯 The effect shifts the temperature of the oldest light by only a few millionths of a degree — like detecting a candle’s warmth from across a continent.
🎬 Mapping cosmic flows in 3D feels like stepping into the navigator's seat in 'Dune', where space travel depends on reading invisible currents.