/sci/ - Science & Math

[Anonymous No.4003263]

suppose you shine red light (from one of those red heat lamps) on a blue object in a room with absolutely no other definite light source

from a physics-standpoint, why are you still able to make out that the object is blue, when the photons from the source (the red light) have less energy than the blue photons being emitted from the blue objects' electrons returning to ground state?

[Anonymous No.4003271]

>thinks you can discuss colour perception only from physics point of view

this is mostly a biology question OP, about how you brain uses relative strengths of signals from different cone cells to interpret colour

[Anonymous No.4003275]

>>4003263
Question is flawed. The colour of an object is defined by the wavelength of light it emits.

So saying that the object is definitely blue is wrong, as it's colour will changed based on the light wavelength it reflects.

[Anonymous No.4003282]

>>4003271
the object emits blue light when exposed to a red light source. how is this not a physics question? the occipital lobe does not see light of a lower frequency and somehow magically determine the chemical properties of the object and go "oh hey! if we shine all the bands of visible light on this it will reflect blue! let's tell the thalamus this!"

[Anonymous No.4003284]

>>4003275
>The colour of an object is defined by the wavelength of light it emits

nope. that is one definition, but not the only one. another definition of colour is how it is perceived. though that won't appeal to the simpler folk of /sci/

[Anonymous No.4003285]

>>4003275
well, it would violate energy conservation, wouldn't it? the red light has less energy than the blue light being emitted. what explains the gap?

[Anonymous No.4003292]

>>4003285
the rest of it is absorbed, ever notice how things get hot when you leave them out in the sun?

[Anonymous No.4003294]

>>4003292
how is anything absorbed? that explains a higher frequency of light, not a lower. with that logic the object would become cooler if it emits higher energy photons.

[Anonymous No.4003296]

>>4003282
the question was about makiing out the object as blue, not whether it emitted blue photons.

the brain can make out an object as blue when it is mostly emitting red photons by interpreting colour in relation to background colour

this is fairly well known. see: http://boingboing.net/2008/02/08/color-tile-optical-i.html

sorry it seems to hang your browser for 10 secs

[Anonymous No.4003304]

>>4003296
interesting, i've never seen that before, thanks! but, that creates the question: is the object actually emitting blue photons, or is it just perception?

[Anonymous No.4003326]

bump

[Anonymous No.4003338]

>>4003296
>that rubiks cube

[Anonymous No.4003339]

>why are you still able to make out that the object is blue

Two hypotheses:

- The lamp you used does not exclusively give off red light but also low intensity blue.

- Self delusion. You *know* that the object is blue and your visual system conforms to your belief.

I just tried it with a red laser, all blue objects that I tested appeared red.

[Anonymous No.4003351]

>>4003339
3rd hypothesis. the brain knows how various colours turn to various shades of red in red light, especially where a known colour is in the field of vision to compare with.

this one, with hypothesis 1, is the current theory

[Anonymous No.4003361]

>>4003294
when a photon hits an atom, it will interact with the electrons of the atom. It will make them excited by adding energy, and then the electron will be unstable, and return to its original state by emitting another photon in the form of energy. Depending on some factors that I don't know, because I don't know much about this topic, a certain amount of energy is absorbed or added or whatever.

[Anonymous No.4003376]

>ITT aspie scitards ignore the brain, ignore the eye, ignore how - apart from lasers - light is a messy distribution of frequencies.

[Anonymous No.4003408]

>>4003376
i'd bang every one of those at least ten times each

[Anonymous No.4003413]

>>4003339
>>4003351
must be my brain

curse the human brain, how can we into science as a species when everything we know and see can potentially be an illusion?

[Anonymous No.4003415]

it is multi-photon absorption

[Anonymous No.4003425]

>>4003376
>brain and eye
>biology

>implying biology is a hard science

[Anonymous No.4003429]

>>4003415
the luminosity of red light needed for blue light to be produced is insane, you fucking mad idiot shit eater

[Anonymous No.4003434]

>>4003425
>implying anyone claimed it was

soft sciences also help us understand the world, as every non aspie/underage accepts