How can we see black objects?

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Pooky

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If Black absorbs light, and we can only see objects because of the reflection of light off them, why is it that we can see black objects?
 
Firstly because NOTHING in our world is truly black...

Secondly, our brains would register the lack of light and it would appear as an object in our vision.

But then I spose it never occured to you, or your teacher at primary school never taught you about things like metallic black where it shines... yes, you know that glint... thats light reflecting off a BLACK object.. amazing isn't it?
 
For you guys out there...If youre ever bare-foot at a shopping spree walking within a road, run to the closest "white" stripes/marks on the tar to cool off ;)
 
Pooky said:
If Black absorbs light, and we can only see objects because of the reflection of light off them, why is it that we can see black objects?
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The type of background plays a part. If you have a black object against a black background then you won't see it. If the background has a higher reflective index than the object, then you should easily be able to see the black object in front of it.

If you've read anything about dark matter in space, then you'd know what I'm talking about.
 
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ToxicBunny said:
Firstly because NOTHING in our world is truly black...
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Black holes are. But thats in our universe, not world so you are right.:D

Highflyer_GP said:
If you've read anything about dark matter in space, then you'd know what I'm talking about.
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I don't see how dark matter has something to do with it. AFAIK only two things are known about dark matter. 1)It has mass 2)It creates a gravitational effect. Would be keen to know how it fits into this though.
 
HavocXphere said:
I don't see how dark matter has something to do with it. AFAIK only two things are known about dark matter. 1)It has mass 2)It creates a gravitational effect. Would be keen to know how it fits into this though.
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And that's how we know that it might exist, because of it's gravitational effect on visible matter. It remains invisible because the background (space) keeps it hidden i.e. their reflective indices are probably identical (or very nearly identical).
 
This is actually a very good question.

He tried to get us to do some of his other homework the other day, but gave up after we succesfully sabotaged that attempt to :)
 
Avatar_5 said:
No, absence of light = DARKness. There is a difference.

Black objects reflects some light, less than other colours. With darkness there is no light to reflect, and thus the colour of the object is irrelevant.
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A practical example is an LCD screen. The black is caused by blocking out as much of the backlighting as possible.

Dark = Black in lay terms or are we speaking more advanced science here?
 
Pooky said:
Please... Enough with the Sarcasm. Your answer was enough, it wasn't necessary to add in that remark at the end.
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Just ignore the toxic derailers. They're probably jealous they didn't think of the question first.:rolleyes:

Wasn't this in the news recently. Something about a discovery of a substance that was the deepest black yet found/made?
 
The answer is quite simple if you understand how the human eye works. If you really want a good "wtf" out of work colleagues try convincing them that data projectors project black onto the screen.
 
PostmanPot said:
I'm beginning to lose further trust in your opinions ;)
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Well that makes one of us, as I had none in yours to start off with :) ,
(only joking), seriously BLACK means absence of COLOUR and since the eye
can't perceive COLOUR without LIGHT we see black in the dark.

LIGHT of different wavelengths creates various colours.
A mix of all the different coloured lights creates white light.
No light = no colour = black/dark.

Fudzy gave a good example with the projector, the dark or the most
dark of all the areas - the BLACK areas have NO COLOUR
projected on them, hence if you have lots of ambient light - your
contrast will be poor and your black will look like grey.
LCD has the same concept.

You can't project BLACK as Fudzy said.

The human eye can only perceive colour if enough light is present - this light activates the cone photoreceptors (colour receptors
and higher resolution) in your retina, however if not
enough light falls on them then only the rhods are activated,
the rods are responsible for low resolution black and white vision
so everything is b&w if you go outside into a moonlit/starlit night
(without any extra light :) ).

OR can someone explain to me the difference between dark/black
in terms of photons and light wavelenghts - ie in terms of physics?
 
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PeterCH said:
BLACK means absence of COLOUR and since the eye
can't perceive COLOUR without LIGHT we see black in the dark.
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Nope black is a colour too, it just doesn't reflect as much light as other colours i.e. it absorbs more light than any of the others. In complete darkness, there is an absence of light, and therefore the colour of an object is irrelevant.

Also, I'd like to know how you can see a black object in the dark when there is no light to reflect off it?
 
Highflyer_GP said:
Nope black is a colour too, it just doesn't reflect as much light as other colours
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Colour is how we perceive the different wavelengths of the light. If its truly black then no light is being reflected, hence no wavelengths, hence no colours. Whether not-so-perfect-black has a colour can be argued either way.

Technically, the object would also have to be 0 kelvin, else it has an infra-red signature.

Also, I'd like to know how you can see a black object in the dark when there is no light to reflect off it?
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With my vampire vision.:cool:
 
Thanks to everyone except ToxicBunny, that answered my question quite well that I thought up myself at home without being given it as homework.
 
.... Noooooooo... First of all, black has to do with visible light. There are frequencies of light that exist, but the human eye just can't pick up. Secondly, if "lack of light" doesn't make something truly black, then black holes aren't black either since their gravitational pull is so strong that it absorbs photons passing close by it so there's a lack of light. No visible light being emitted: black. Light emitted: Not BLACK black. Done.
 
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