Credit: Science - NASA, ESA, A. Fox, P. Richter et al.
Image - D. Nidever et al., NRAO/AUI/NSF, A. Mellinger, LAB Survey, Parkes, Westerbork, and Arecibo Obs.
Explanation: In an
astronomical version of the search for the source of
the Nile, astronomers now have strong evidence for the origin of the Magellanic
Stream. This composite image shows the long ribbon of gas, discovered at
radio wavelengths in the 1970s, in pinkish hues against an optical all-sky view
across the plane of our Milky Way galaxy. Both Large and Small Magellanic Clouds, dwarf satellite galaxies of the the
Milky Way, are seen near the head of the stream at the right. Data from Hubble's
Cosmic
Origins Spectrograph were used to explore abundances of elements along
sightlines to quasars that intersect the stream. The results indicate that most
of the stream's material comes from the Small Magellanic Cloud. The Magellanic
Stream is likely the result of gravitational tidal interactions between the two dwarf galaxies some 2
billion years ago, the Small Magellanic Cloud losing more material in the
encounter because of its lower mass.
