Source: Hubblesite.org

I’ve seen this image several times, and thanks to a lot of Terry Pratchett books and a bit of pareidolia, I always thought that this looked kind of like a silhouette of the Great A’Tuin emerging from the mists of  another universe. Still too far away and obscured by clouds to make out the elephants and the disc, you can nevertheless make out the head and the beginning of his shell. And of course the sun that orbits his mighty body is the cause of the back-lighting.

Now, quite apart from the fantastic image that I created in my own head, I always just figured that the silhouette was actually created by some kind of dense dust cloud getting in the way of the light behind it. The shape was surely an accident of history and all the dust and gas thrown off by some star or galaxy formed what looks to me like a giant turtle, and what must look to others like an amorphous blob, or as Phil Plait, the Bad Astronomer himself, says “it’s always reminded me of a Shuttle Orbiter”.

Then Phil Plait pointed out that things are not as they seem.

Source: European Space Agency

This is an image of a slightly larger area of the sky viewed in the infrared. You shouldn’t be able to tell by looking at this image exactly where the original image was because it shouldn’t look even remotely the same. The dark clouds of dust and gas that usually cause what look like empty spaces in…um…space block the visible spectrum of light, but they are usually still hot, and so glow in the infrared. A’tuin should be glowing just like everything else in this image. And yet I can see clearly that he is part of the green blob at the top of the image. Why is that?

It turns out that it’s not glowing because there’s nothing there to glow. A’tuin still appears in the image because he was literally never there to begin with. The silhouette was never a silhouette at all, but a whole different kind of black hole. It’s a big area of nothingness in the middle of that bright cloud of somethingness.

This is why I love science. How quickly and completely does our universe change with just a little bit of information! Things that we could clearly see and thought we understood turn out to not only be different than we thought, but may in fact turn out to have never actually existed in the first place!