Of course, dust isn't the only particle which can reflect light, and make an orb on the picture. Raindrops, snow flakes, mist, and even gnats can reflect the flash, and make orbs in the photograph. When there is a fine mist hanging in the air, hundreds of little orbs can show up in a single photo.

There is even one photograph of orbs posted on the internet, which was taken at night, with the camera looking through a car's window. The "orbs" presented are, rather obviously, the reflections of pairs of headlights from other cars on the road.

Other orbs are caused by something called "lens flare". This is when there's a bright light, like the sun, in the picture or just outside of it. Lens flare is caused by multiple internal reflections in the camera's lens. You're likely to see examples of lens flare when watching the winter olympics. The camera man will be following a skier down a hill, and as he ski's past the morning sun, a line of orbs will scan across the screen.

Another type of ORB which you'll probably never see is Ball Lightning.

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