Gender: Male Location: Southern Oregon,
Looking at you.
How do we see?
Are photons the only thing we can see?
It sounds simple, but I don’t know for sure. If something does not give off light or even reflect light, then it would look black, and we would not be about to see it. Is that correct?
My 2-cents worth: if we define "seeing" as involving reception of photons, then by definition we would "not see" it. However, we could still notice it via the absence of light in that vicinity.
__________________
Shinier than a speeding bullet.
Yes, we SEE because our eyes absorb photons emitted or reflected by the objects around us.
Objects like black holes and dark matter neither reflect nor emit light, so we can't see them/it.
As Mindship says, we can detect black holes through other means though.
__________________ "Those who can make you believe absurdities can make you commit atrocities."
-Voltaire
"That includes ruining Halloween because someone swallowed a Bible."
"I just thought you were a guy."
"... Most guys do."
Well if an object didnt absorb or reflect light, wouldnt we just see through it, and so, we wouldnt notice the lack of light, we'd just the the area behind such an object.
__________________
"Give a man a fire and he will be warm for a night. Set a man on fire and he will be warm for the rest of his life"
Gender: Male Location: Drifting off around the bend
Re: How do we see?
The stimulus for vision is light, electromagnetic energy. So yes photons are what we see. We see electromagnetic energy at wavelengths between 400 nm to 700 nm, so not all photons are "seen" by humans.
Gender: Male Location: Drifting off around the bend
You are a physics person if I remember correctly. I have a question about black holes. Black holes often spew stuff out in a predictable pattern, fact or theory I don't know, if a black hole were viewed from a point where this occurred toward the observer, is it visible? Or does the material collapse back in before any light escapes?
I would think so. However, Shaky did begin his question with, "If something does not give off light or even reflect light..." He didn't say anything about also not absorbing light.
__________________
Shinier than a speeding bullet.
Gender: Male Location: Southern Oregon,
Looking at you.
Anything that does not give off, reflect or absorb light, would look really strange, if you could see it at all. Maybe that is what dark matter is, invisible matter.
For what I know carbon monoxide emitts, and reflects in the infrared part of the specter, and absorb other colors.
That why the greenhouse effect happens, the sun light enter the atmosphere and is converted to heat, when this heat tries to get out of the planet in the form of infrared radiation, it is reflected back again.
no. To "see through" an object, the object would have to bend light around it.
Here's a scenerio: You are standing in a room. A box is located directly between you and the wall. If this box were to not reflect light, you would simply see a true black sillouette of the box. You would not be able to see the wall behind it as the box is still there, obstructing the photons reflecting off the wall from reaching your eyes.
To be able to "see through" the box.......the box would have to be extremely massive, bending space-time around it.
Our perceptions.................only that............some have others that we do not and can see other things we do not.........I do not discount them.....too many people have testified to them..................
KMC Community Forums
How do we see?
Jul 7th, 2006 02:52 PM
If you shine photons on a carbon monoxide molecular, it would absorb the photons, wouldn't it? 
Don't do that again. Leave it to the pros. 
