The Magellanic Stream, which extends almost halfway around the Milky Way, is only detectable at radio wavelengths, and made visible in the wonderful composite image above.


Credit: Science – NASAESAA. Fox, P. Richter et al.
Image – D. Nidever et al.NRAO/AUI/NSFA. MellingerLAB SurveyParkesWesterbork, and Arecibo Obs.