This glowing green bubble is planetary nebula IC 1295, which lies about 3300 light-years away in the constellation Scutum. A star of around the same mass as the Sun shrinks to form a white dwarf at the end of its life, in the process becoming unstable and repeatedly ejecting gas, forming the multiple shells that here look like cell walls. This example, taken with the VLT, glows green from ionized oxygen; the nebula itself is roughly 2 light-years across. (ESO)
This image is published in the June 2013 issue of Astronomy & Geophysics.