Why do radio telescopes detect supernova remnants through interstellar dust?
This nebula is the product of a supernova explosion; in this section, the blast wave has encountered an area of dense interstellar gas, creating turbulence in the wave and causing it to glow. The picture is a composite of three images taken by the Hubble Space Telescope.
Radio telescopes are able to detect supernova remnants through interstellar dust because the radio waves they emit are long enough to penetrate the obscuring clouds that block visible light.12
Many supernova remnants are powerful sources of synchrotron radiation, which is produced by high-energy electrons spiraling in magnetic fields at speeds near the speed of light. This radiation is emitted across a broad range of wavelengths, including the radio spectrum. Because these radio waves can pass through the dense, dusty regions of the Milky Way Galaxy that hide these objects from optical telescopes, radio observations allow astronomers to identify and study remnants that would otherwise remain invisible.132