> Without objects to reflect the light, we do
> not see the light.

> When I look at a book, for instance, I see
> the book sitting on the shelf. I do not see
> the light travelling from the book.

> If I shine I light in the dark, I see the
> light reflecting off the object the light
> shines on. But I do not see the light
> travelling between me and the object. I will
> see it if there are particles like dust or
> smoke in the air between me and the object.
> But if there are no objects in the air to
> reflect the light I do not see the light.

> If I stand to the side of you I do not see
> light entering your eyes.

Okay, I see (??) what you're getting at -- you're saying we can't see the MOVEMENT of light -- right?

Just for the sake of accuracy, I'll respond to this statement:

> Without objects to reflect the light, we do
> not see the light.

This may be true in certain cases -- if the light were in a narrow enough beam that it wasn't enveloping everything around you. But if your eyes were in the path of the light, you'd see it.

For example, with nothing between you and the sun except the vacuum of space, if you looked at the sun, would you see the light? Of course.

What we refer to as (visible) light is simply a portion of the electromagnetic spectrum which our eyes can convert to electrical impulses. So if our eyes are in the path of those wavelengths, we'll see the light regardless of whether they're reflected or direct.

I feel like I'm back in college -- fun stuff! :o)

Best,

Paul