Cygnus Loop

This GALEX image of the Cygnus Loop nebula could not have been taken from the surface of the Earth because the ozone layer blocks the ultra-violet radiation emitted by the nebula.

The Cygnus Loop (radio source W78, or Sharpless 103) is a large supernova remnant (SNR) in the constellation Cygnus, an emission nebula measuring nearly 3° across.[1] Some arcs of the loop, known collectively as the Veil Nebula or Cirrus Nebula, emit in the visible electromagnetic range.[1] Radio, infrared, and X-ray images reveal the complete loop.

  1. ^ a b Murdin, P. (2001-01-01). Encyclopedia of Astronomy & Astrophysics. CRC Press. p. 996. ISBN 978-1-000-52303-4.