Free Thinkr

Hehe.. I've done that one.

Gurdur

Actually, under the right (theoretical) conditions, a youngish, healthy human eye can register one photon - at least that was what I learnt in one seminar, though I never did experimentation on this.

BTW, the eyes and the optic "nerves" are properly speaking not seperate organs or nerves, but rather specialized extensions of the actual brain --- and more, they are extensions of the Zwischenhirn (damn, damn, this is what I get for studying neurology in German -- I can't think of the English word !), the middle brain, the part of the brain dealing with emotions and memory, so when you look into a person's eyes, you're looking into their soul.

[ July 01, 2002: Message edited by: Gurdur ]</p>

Ovazor

In principle yes, but there occurs "false" detections in the phototreceptors due to thermal movement, which means that the visual system tends to ignore one-photon stimuli. It is estimated that between 50 and 150 photons are required to strike the cornea for a discrete signal to be detected. Of these about 10% actually reach the photoreceptors.

Late Cretaceous: The pigment in the rods is called rhodopsin, not rhodamine.

Max Bane

Limbic system, I'm pretty sure.

Jeremy Pallant

Well, I've experienced total darkness in a cave or two. For some reason I love caves.

However, for total natural darkness in the open, I offer you this. Several months ago, back in February, I took a brief vacation in one of my favorite locations, Death Valley. So that I would return to Tucson at a sane hour, I left my motel in Beatty, Colorado at around 4 am, and headed south through the Valley. About a half-hour later, I stopped specifically to see what the stars looked like without pollution from artificial light. It was damned cold, but to see the stars without a human light source anywhere in sight is a magnificent experience. To make things perfect, there was no moon at all. Truly a profound experience.

Jeremy Pallant

Well, I've experienced total darkness in a cave or two. For some reason I love caves.

However, for total natural darkness in the open, I offer you this. Several months ago, back in February, I took a brief vacation in one of my favorite locations, Death Valley. So that I would return to Tucson at a sane hour, I left my motel in Beatty, Colorado at around 4 am, and headed south through the Valley. About a half-hour later, I stopped specifically to see what the stars looked like without pollution from artificial light. It was damned cold, but to see the stars without a human light source anywhere in sight is a magnificent experience. To make things perfect, there was no moon at all. Truly a profound experience.

lpetrich

Zwischenhirn = Diencephalon (thalmus, hypothalamus, etc. inside the main bulk of the brain).

punta

Originally posted by liquid:
If you are interested in visual/neural phenomena, why not have a look at <a href="http://nivea.psycho.univ-paris5.fr/ASSChtml/ASSC.html" target="_blank">change blindness</a>

thankyou. that was interesting and fun.

lynx

that was interesting. i think it explained some visual problems i've run into, something that no doctor has been able to do. thanks for the link.

Agnostic Journyman

I know of both of these things personally. In the 80's I was in the Navy on a cruiser. We were literally thousands of miles to sea. At night we would "darken ship", which meant dousing all the white fluorescent fixtures and turning on red incandescent lights near the floor, for one thing. Often after my final watch of the day I'd venture out onto the ship's fantail.

Upon leaving the light locker, it's like diving into a sea of ink. You can't see shit. I'd make my way toward the stern, using the lifeline as a guide, and seat myself on a bit (like a bollard used for mooring the ship). In about twenty minutes, with no moon, no clouds, I could see EVERYTHING. The ship rocking gently, the wake in the water, distant ship lights on the horizon.

Especially beautiful, along with a completely light-pollution free star studded sky, was the phosphorescence in the sea water stirred up by the ship's wake. On some nights I could actually see the shadow of the ship's screws turning in the water.

Truly a profound experience indeed.