Cosmic Static: Dust or Molecules? express
The night sky glows not only with stars. Between them lies a faint microwave radiance that astronomers have noticed for three decades but couldn't explain. One idea: the culprits are polycyclic aromatic hydrocarbons — molecules like tiny soot flakes that spin in space and, like miniature antennas, emit radio waves.
Fresh observations from the DIRBE instrument on the COBE satellite compared this glow with a dust map and a map of the molecules' own emission. It turned out that the microwave signal matches dust much better than molecules, like engine noise coming not from the belt but from the whole body. This means either the molecular "soot" isn't emitting, but other dust grains are, or the molecules glow in microwaves only under special conditions we don't yet understand.
If the mysterious glow originates not in molecules but in ordinary dust, then we've been misreading one of the most common "signatures" in our galaxy. And that matters for all-sky maps used to search for traces of the Big Bang.
Polycyclic aromatic hydrocarbons are not just cosmic "soot." They form when grilling meat over charcoal and in exhaust fumes, so space and barbecue share the same chemistry.