Astronomers are trying to capture the radio echo of the Big Bang — a faint glow that fills the entire universe. But the receiver is choking with noise: our Galaxy is packed with glowing interstellar dust, whose emission can easily be mistaken for a signal from the distant past.

Previously, dust was thought of as a uniform haze. New research shows it's layered in clumps with different temperatures and densities. Ignoring this patchiness makes it easy to confuse dusty ripples with the echo of the Big Bang.

Key takeaways: The Galaxy is three-dimensional, so a single dust layer isn't enough. Telescopes need observations at many frequencies — like a radio receiver with multiple bands. And you can't just average data across the sky — the signal gets lost. Paradoxically, the interfering dust itself is the ashes of dead stars, scattered by supernova explosions.