In photos, why do some people get red eye more than others?

Red eye occurs when the bright flash from the camera enters the eye and reflects off the retina back into the camera. I suppose one reason that some people are more susceptible is that they probably stare directly into the camera more. Staring straight back increases the chance of red eye. The other reason would be related to the size and color of a person's iris, which controls how much light can get into the eye. (I wonder if blondes have more red eye?) Cameras with red eye reduction turn the flash on early in order to cause the subjects iris to contract to reduce the amount of light getting in (and out) of the eye.

Edit: After reading the comments, I looked further into the effect of eye color on causing red eye. It's not the color of the iris that has an effect, it's the amount of melanin in the eye. Melanin absorbs the red light, reducing the amount of red light reflected back to the camera.

How does the sun create dust?

I believe that the young man who asked this questions was noticing that you can see a lot of dust when the sun shines through the window. The reason for this has to do with contrast. When you typically observe an object, your observation is based on a change in contrast/color from the surrounding view.

Try this experiment...

• Find a room with a white wall (or any kind of white background)
• Tape a small piece of white paper on the wall (say about the size of a quater)
• Take another small piece of paper, make it black by writing on it with a pen, and also stick it on the wall
• Go as far away from the wall as possible and look at the pieces of paper.
• Which piece of paper is easier to see?

Pieces of dust are so small, that they are generally difficult for our eyes to see. However, when exposed to bright sunlight, the bright light is reflected off the dust particals making them appear very bright against a dark background.

On a side note, all of the matter on the planet was originally created in the stars many billions of years ago. So, I guess you can say the sun (or rather, some other star) creates dust.