We all do it. We see patterns and attach significance where there is none: a pig in the clouds, a rabbit in the moon, a face on Mars, Jesus on toast. This phenomenon is a form of pattern recognition known as apophenia, and some researchers believe that it's a trait that has helped humanity survive from its very earliest days.
It can also be a lot of fun. Take a look at the night sky with a stargazing guide in hand and see if you can see the shapes for which the constellations were named, or spend a half-hour on a nice day looking for shapes in the clouds.
For astrophotographers -- such as Finland-based J-P Metsavainio, AKA AstroAnarchy -- the game can get even more fun, with gorgeous nebulas added into the equation. The clouds of gas, dust and light are often, like constellations, nicknamed for terrestrial objects that humans see in their shapes -- the Horsehead Nebula, for instance, or the Butterfly Nebula.
Some nebulas don't have nicknames -- but that doesn't mean we can't find shapes inside. Metsavainio -- whose work has been published by NASA, National Geographic, Universe Today and others -- liked to play the pattern-recognition game too. Due to an extended period of solid cloud cover, he hasn't been able to take photographs -- so instead, he's taken a collection of his photos and added in images of what the nebulas look like to his eyes.
"We are easily seeing quasi logical forms in random shapes since we have a most powerful shape recognition machine in our brains," he wrote. "Based on previous phenomena, I made a funny collection out of my photos. There is the original version of my photo and then the same photo as I see it in my head."
Some of the images have real nicknames, such as the Wizard Nebula. This makes sense: when an association is already suggested, the viewer finds it easier to recognise that association themselves. Some of the images, however, Metsavainio has chosen for himself.
Click through the gallery below for a small selection, or visit Metsavainio's blog for the full set. You can also visit his YouTube page to see his 3D animations of nebulas based on stereoscopic imagery.