Apparently God has a well stocked humidor.

Einstein postulated that gravity from matter bends space, like a bowling ball on a bed bends the mattress. Light will follow that bend in space the same way a marble rolled across the bed will curve from the bowling ball’s dip. If there is some massive object out there in space, and some galaxy beyond it, the light from the more distant galaxy will bend as it passes by the intervening material. We see that as a distortion in the shape of the galaxy. This is called gravitational lensing, and can be used to map out the location of dark matter. So even though we cannot see DM directly, we can see its effects.

This image is of the galaxy cluster CL0024+1652 (higher resolution version), a galactic city located a whopping 5 billion light years away. That means the light we see from this cluster left it five billion years ago, so we’re seeing this structure as it was when the Universe was just 2/3 its present age. Almost every small object in that image is a galaxy, and all of them are held sway by the cluster’s gravity, orbiting the center like bees flying around a beehive.

It has long been thought that every large object in the Universe is surrounded by a halo of dark matter — unseen, mysterious, yet profoundly influential in the life of normal matter. Dark matter (or just DM for short) gives off no light, and does not interact with normal matter directly– a cloud of it could pass right through you and you’d never know. But, like regular old matter, it has gravity, and that can betray its presence.

Hubble finds dark matter 'smoke ring'. (Bad Astronomy)