Something really big exploded 5,000 to 10,000 years ago and this is what’s left.

The Cyngus Loop or Veil Nebula is the dust and gas left over when a supernova exploded in the area of the Cygnus constellation.  The explosion was so bright that people could see it naked eye.

But they didn’t write about it.  The first written language was invented by the Sumerians 5,200 years ago, probably too late for anyone to mention a temporary bright spot in the sky.

Nowadays the remnants are too dim to see without a telescope and some sections such as the Witch’s Broom have been named separately.

The entire Veil, above, isn’t visible except in the ultraviolet range.  If we could see it we’d be impressed.  It’s six times the size of the full moon.

p.s. Many birds can see light in the ultraviolet range, so this is probably what the Veil looks like to them.

(ultraviolet image of the Cygnus Loop Nebula by NASA/JPL-CalTech via Wikimedia Commons. Click on the image to see the original)