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What is light visible or invisible?

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734472.  Wed Aug 18, 2010 5:11 am Reply with quote

I am reading the 2006 book " the book of General Ignorance" and am having a debate with my friend as to what is the colour of light. The book suggests that light is invisible, "you can't see light itself, you can only see what it bumps into. A beam of light in a vacuum, shining at right angles to the observer, cannot be seen... If light itself was visible, it would form a kind of fog between your eyes and everything in front of you." This is all very well and makes sense but if there is some more scientific background/information as to why this is so that would really help me out[/quote][/b]

734477.  Wed Aug 18, 2010 5:33 am Reply with quote

Light is only visible if it enters your eye, if you are perpendicular to a beam of light then the only way you can see it is if that beam strikes something and scatters it such that some of the light is no longer perpendicular to you and can enter your eye. This is why smoke puffers are used in optics labs to show the track of laser beams.

734481.  Wed Aug 18, 2010 5:59 am Reply with quote

Think about it this way - if light was visible, we wouldn't be able to see anything else.

Spud McLaren
734545.  Wed Aug 18, 2010 2:35 pm Reply with quote

<pedant switch to overdrive>

But, due to the eye's modus operandi, we can't see anything else.

We interpret the way light scatters, reflects and refracts off objects to gain some idea of the properties of those objects - but all we see is the light, not the object.

<pedant switch to neutral>

Sorry, Neo - I know what you mean.

734556.  Wed Aug 18, 2010 4:13 pm Reply with quote

What do you see if you look directly at a light source, then?

Not arguing, just enquiring.

734571.  Wed Aug 18, 2010 5:06 pm Reply with quote

Depends on the light source, if it's strong enough, nothing ever again.

734670.  Thu Aug 19, 2010 3:26 am Reply with quote

What do you see if you look directly at a light source, then?

Bono's arsehole.

734683.  Thu Aug 19, 2010 3:34 am Reply with quote


734759.  Thu Aug 19, 2010 6:40 am Reply with quote

Turn away from the light...


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