NASA's Astronomy Picture of the Day (APOD) is a well-established feature on the Internet. Many are of interest only to specialists, but now and again one comes up that's a work of art in its own right. This one seems to qualify.
It's of the M2-9 Planetary Nebula, which is about 2,100 light years from Earth. The photograph was published on September 15th this year. (Follow that link for a much larger version of the image.)
Spectacular, isn't it? Does anyone know how large those hourglass shapes are, in terms of light-years in length or other measurements? Wikipedia doesn't say.
Peter
