There's a wow factor here. I usually know within a second or two of seeing a picture whether its a sure thing for Astronomy Picture of the Day because I just say wow, what is going on there.

I think that a lot of these would look great in a gallery. They are very different, there's lot of different colors, and contrasts, textures and they have the added bonus of being scientifically interesting.

The earth at night is one of [their] most popular images. And you can click on the image and that will bring up a higher resolution image that you can find your hometown on. Its not just one shot, it was built up by defense satellites.

Recently people put together this panorama from the moon and you can see as if you are turning 360 degrees around. And so there's this wow factor. You can look as if you were standing on the moon and see what the astronauts saw.