Nanodiamonds studding space or dust particles refracting
starlight? What causes the mysterious red and blue glows that
pervade vast areas of the Milky Way has never been certain, but
silicon oxide nanoparticles are the latest idea to fit the bill.
The red glow, or Extended Red Emission, was discovered more than
20 years ago. Astronomers suspected that particles in
interstellar dust clouds were absorbing starlight and emitting
red light, but nobody could pinpoint the nature of the
particles. Things got even more complicated with the discovery
in 2005 of luminescent blue glows in some regions of
interstellar space. "Nanodiamonds in the sky could explain the
red light, but not the blue light," says Ashraf Ali, an
astrochemist at the NASA Goddard Space Flight Center in
Maryland. "What's more, nobody knew how they could have formed
in space." Instead, Ali and his colleagues believe that
nanoparticles of silicon oxide are responsible. ...