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Q & A: seeing things

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Most recent answer: 05/15/2011
Q:
If we can only see things when light reflects off of them, and outer space is totally black because there's nothing for the sun light to reflect off of for us to see,then how can we see the sun? Does the sunlight reflect off of itself? I mean, the sun itself is light and when light is moving it doesn't go backwards, right? Then it can't go back to reflect itself, and if it doesn't get reflected then we can't see it, so what are we seeing?
- Anonymous
A:
Here's another way of picturing this. Your eyes pick up light signals. So you can only see things if they are giving off light. That light can either be reflected light from outside or internally generated light. The light you see from the sun or from a light bulb was made in those objects.

That's really all there is to it. Reflection is just one of the ways that light can come from something. I'm curious about where you heard that we can only see reflected light.

Mike W.

(published on 05/13/2011)

Follow-Up #1: seeing things again

Q:
were did we hear that we see only reflected light ,here are some resources physics book physics teacher tv and many others. hope you answer what actually we can see.
- Rena (age 15)
A:
Hi Rena- Thanks for the information. You're making us feel very good about keeping this site going, since it seems that there's so much odd misinformation circulating around out there. Somebody has to help counter it.

So again- think about your eyes. Why would they care what the source of the light is, so long as it gets to them? You can see light in the right wavelength range whether it started in the thing you're seeing or started somewhere else and then bounced off the thing you're seeing.  If those various sources really said otherwise, they're just plain wrong.

Mike W.

p.s. If you have a way of sending any printed or online source of that misinformation to us, we'd be pleased to feature it in our "We Call Baloney" section.

p.p.s. Aha, here's one such source of baloney, one of the usual suspects:

(published on 05/15/2011)

Follow-up on this answer.