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4934.  Tue Jan 20, 2004 7:14 pm Reply with quote

4936.  Tue Jan 20, 2004 7:21 pm Reply with quote


4944.  Tue Jan 20, 2004 7:33 pm Reply with quote


4945.  Tue Jan 20, 2004 7:33 pm Reply with quote

Unsourced but QI bits from the QIDb:

It is possible to read by the light produced by half a dozen large fireflies.

17th Century German scientists believed it was possible to make an extract from fireflies and use it to light houses.

In World War Two, the Japanese used powdered bioluminescent crabs to read maps at night.

Krill, the minuscule shrimp eaten by blue whales, are bioluminescent.

4946.  Tue Jan 20, 2004 7:37 pm Reply with quote

Gosh, garrick, your link reminded me with a powerful rush of seeing bioluminesence on a beach in the Seychelles for the time, twenty-two years ago, when I was young...

Ars Longa, vita brevis

4947.  Tue Jan 20, 2004 7:38 pm Reply with quote


Sophie J
4974.  Wed Jan 21, 2004 8:15 am Reply with quote

And why is it that deep-sea fish advertise their presence with bioluminescence anyway? Surely this is like going round with a note saying "eat me" pinned to your back.

Bioluminescence is visible light made by living creatures. Some creatures glow because they have bioluminescent bacteria growing inside them. There is a little squid known as the “fire shooter” that has a specialised light organ inside it in which bacteria grow. The squid squirts this ‘blue light’ into the face of a predator, enabling it to escape while the predator is blinded. I agree it’s still unfortunate that the squid can be seen because of the blue light though.


4975.  Wed Jan 21, 2004 10:06 am Reply with quote

From Sophie's link above, it seems that bioluminescence has survival value (as it jolly well ought if Darwin got anything right at all). Some creatures use their light to help them find food, some use it to help them find mates, some use it to defend themselves against predators or for any combination of these three.

Some fish, like the Black Dragonfish (Melanostomias bartonbeani - an evil-looking creature if ever I saw one) have light organs under their eyes that they can use like a flashlight to help them search for their prey. I suppose if you tend to be predator rather than tending to be prey, that would be helpful. Others, like the Anglerfish (Melanocetus johsonii - another evil-looking bugger) attract their prey with a glowing lure that dangles from the end of an organ like a fishing pole attached above their jaws. When the unsuspecting prey tries to nibble at the tempting bait, it finds itself instantly engulfed in a mouthful of needle sharp teeth.

Another use of bioluminescence is to help attract mates. Sex signals which send messages like "Eligible female seeks compatible male" can be sent using a special flash code, as fireflies do on land, or light organs can have a shape or pattern that is specific to a particular species and allows a member of the opposite sex to recognize a potential mate. Although at one time it was thought that each lure was designed to attract special prey, it now appears that the unique shape has evolved to attract a male of the same species who recognizes his future mate by her lure. Quite literally, she would be alluring.

Many male angler fish are tiny compared to the females and some have no no bioluminescent lure and depend on their mate for food. When they find each other, the male latches on to her side where his lips actually fuse with her flesh and her blood stream flows into his body providing him with the nourishment he needs to survive. In return, he provides her with the sperm she needs to reproduce. This doesn't sound like an entirely fair deal to me, but I suppose if one looked like a female anglerfish it would be a case of needs must.

A third use for bioluminescence is to blind and distract attackers. Just as squids squirt out an ink cloud to distract a predator, many animals in the ocean can squirt out a glowing cloud and then do a tail-flip backwards into the darkness. Another defensive use of bioluminescence in the ocean is as camouflage. In the open ocean there are no trees or bushes to hide behind, there is only dim blue light filtering down from above and darkness below. Many animals produce a very distinctive silhouette, easily seen by a predator swimming below. Creatures with bioluminescent light organs on their bellies can disguise their silhouettes. Because seawater scatters light, these point patterns tend to blur at a distance and the bioluminescence exactly matches the color and intensity of the dim blue light filtering down from above, so these animals can hide, even in the open ocean.

There is another rather clever defensive use of bioluminescence. A single-celled dinoflagellate produces a bioluminescent flash when disturbed because this will attract the attention of bigger fish, rather in the manner of a householder who is attacked by a burglar calling the police for help.

4976.  Wed Jan 21, 2004 10:16 am Reply with quote

How is an interesting question, as well as why. Again, from Sophie's link:

Light is produced when an electron that has previously absorbed energy and moved to a higher orbit releases the energy in the form of photons and falls to a lower energy state. We tend to associate heat and light because we are used to thermal excitement from the sun or a candle or a light bulb. However, in bioluminescence the electrons are excited by a chemical reaction that generates light but no heat.

In 1887 a scientist named Raphaël Dubois isolated light producing chemicals from the common piddock, which is a clam that bores holes in rocks. He discovered that if he ground this clam up in cold water, he saw light in the water, which glowed for several minutes, indicating that he had extracted the light-producing chemicals from the clam's tissues. He then found that if he made a hot-water extract from another clam and added this to the original cold-water extract, he could reactivate the light reaction. Dubois called his hot-water extract luciferin and the cold-water extract luciferase. Although these terms are used to describe the substrate and the enzyme in any bioluminescent reaction, different creatures produce very different versions of these chemicals.

One result of different chemicals is different colours. Bioluminescence comes in all colours. However, the commonest colour of bioluminescence in the ocean is blue. Since blue is the colour which penetrates farthest through water, it is not surprising that this is the colour which has evolved through natural selection most often.

4978.  Wed Jan 21, 2004 10:24 am Reply with quote

The units of measurement for light energy are photons per second (human scale measurements like lumens or footcandles are less useful when you're dealing with bacteria!) A single bioluminescent bacterium will emit 103 to 104 photons per second. At the peak of a flash, a single bioluminescent dinoflagellate will emit 1010 to 1011 photons per second. A 100 watt light bulb emits about 1018 photons per second. Because it is possible to pack millions of bacteria into a very small volume, some of the brightest bioluminescent animals in the ocean, like the flashlight fish, use bacterial bioluminescence.

However, electric light bulbs are a lot cheaper and more efficient than trying to maintain any kind of biological system.

5371.  Fri Jan 30, 2004 12:04 pm Reply with quote

Can we make a stretch of a connection between electroluminescence and bioluminescence? Some stories are too good to pass over.

Backlit handbag, anyone?

Electroluminescence shines light where it's never been before

THADDEUS HERRICK, The Wall Street Journal
Thursday, January 29, 2004

(01-29) 05:38 PST (AP) --

For years, women's handbags have been something of a black hole, dark, disorganized and a formidable challenge to those looking for keys or lipstick.

Technology may soon change that.

"The answer is light," says 35-year-old Axel Bree, who with his 31-year-old brother, Philipp, is co-president of Bree handbags in Germany.

Or more specifically, the answer is electroluminescence, a technology that generates a cool, gentle light -- but not heat -- when the chemical coating on plastic is electronically stimulated.

That's just one of several ways that EL differs from traditional light bulbs. Incandescent bulbs burn out and are inefficient: Much of the energy they use is thrown off as heat, not light. EL lighting, on the other hand, uses electricity to light up specially treated plastic. This chemically treated plastic generates so little heat that it remains cool to the touch, doesn't burn out and uses less energy. EL has been around for decades, but for years researchers puzzled over applications for it because of its low light intensity and the fact that originally it only worked on flat, rigid spaces.

A recent innovation in plastics is likely to give the technology a big boost. Scientists and engineers at Bayer AG say they are among the first to market a plastic film that not only lights up, but also can be molded into three-dimensional shapes. Bayer teamed up with Swiss lighting company Lumitec, which licensed the EL technology to Germany's Bree in an exclusive deal. Last fall, Bree unveiled a big, portfolio-size leather purse with a clear, flexible 6-inch-by-5-inch plastic sheet that glows inside the bag. The panel, powered by a nine-volt battery and controlled by a tiny switch tucked away inside the bag lining, is bright enough to light both sides of the purse's cavernous interior.

In April, Bree plans to sell its first two electroluminescent leather-and-nylon bags, for 250 euros ($315) and 400 euros respectively. The bags aren't sold in the U.S., but shoppers will find them at Bree stores in Europe, Asia and Canada. American buyers can order the bags through Taschen Inc., in Toronto, the company says.

The new use for EL opens up an array of new possibilities for electroluminescence in the $40 billion global lighting market. Scientists and engineers predict, for example, that in a matter of years, clothes that glow could be all the rage. Auto makers are pondering ways to use its soft, glowing light for car interiors, and lighting designers see a growing niche for EL in interior design.

Bayer's foray into lighting underscores a broader trend for chemical companies that seek to shed mature assets and develop new, more profitable applications for their products. As the chemical makers try to reinvent themselves, companies such as Bayer, Dow Chemical Co., Midland, Mich., and DuPont Co., Wilmington, Del., are joining forces with smaller lighting businesses to develop technology that requires only a fraction of the energy used by an incandescent or even fluorescent bulb.

"Light bulbs owned the last century," says Robert Kumpf, vice president of business development for Bayer Polymers, Americas. "Modern lighting technology will own the next."

One such "modern" form of lighting, using LEDs, or light emitting diodes, is gaining prominence in traffic lights, electronics control panels and eventually even automobile headlights. Strategies Unlimited, a market-growth research firm in Mountain View, Calif., predicts the $2.7 billion LED market will more than double to $5.5 billion by 2008.

EL is another promising alternative to the incandescent bulb, though its potential is still unclear, analysts haven't yet predicted its total market potential.

The $350,000 2002 Mercedes Maybach is the first car to boast an electroluminescent headliner -- the ceiling of a car's interior -- stylishly bathing the inside of a vehicle in light. The new EL light gives auto designers more flexibility, since bulbs tend to take up considerable space, eat up more power and give off heat.

Frederick The Monk
5374.  Fri Jan 30, 2004 12:42 pm Reply with quote

Another way to make some things give off light is to squeeze them. Don't believe me? Then try this at home tonight.

You will need:
A 'wintergreen' throat sweet - available in the US but I'm not sure I've seen them in the UK.
A pair of pliers.

Firstly place sweet in jaws of pliers. Now switch off the light (preferably leaving you in complete darkness). Now begin to gently squeeze sweet with pliers. The sweet will glow gently thus demonstrating the phenomenon of piezoluminescence.

Shortly after this the sweet will shatter leaving you to spend the rest of the evening picking sticky shards of confectionery out of the carpet.


Sophie J
6234.  Thu Feb 26, 2004 6:45 am Reply with quote

The bobtail squid, 'Euprymma scolopes' has a light-producing organ on its underside that is home to lots of specialised luminescent bacteria, 'Vibro fischeri'.

The squid effectively turns its belly into a flashlight by magnifying the glow from the bacteria and directing it into a beam. It has lots of mirror-like, silvery reflector plates and a lens made of muscle on its underside.

The squid uses this beam of light from its belly to cancel out the shadow its body makes on the shallow seafloor in the moonlight. It's therefore almost invisible to predators.

s: Science, vol. 303

6684.  Sat Apr 03, 2004 1:31 pm Reply with quote

A transformation in computer and communications technology has been predicted by researchers in Sydney studying Australian lobed comb jellyfish. These jellies use photonic crystals to display dazzling iridescent colour flashes down their tentacles. The crystals control exactly what colours of light they reflect, and physicists believe that such fine manipulation of light, if it could be produced by synthetic crystals, could form the basis of faster computer chips, based on controlling light rather than electrons. This would hugely speed up transmission through optic fibre networks and increase the number of channels of information that could be carried by a single optic fibre from 40 to as many as 10,000.

Unlike chemical pigments, colours generated by photonic crystals do not fade, so there could also be a revolution in the permanence of colour photography.

Photonic crystals have been found in sea mice (small worms), butterfly wings and weevils as well as jellyfish, and recently they have been reported in peacocks' tails.

Natural photonic crystals vary in form. Some are planar structures, some tiny balls called nanospheres. Some have hexagonal cells while others, such as those now discovered in the lobed comb jellyfish, have parallelogram-shaped building blocks. Colour can vary depending on the direction from which the crystal is viewed, according to the angles in its structure.

Researchers plan to look at the sea mouse genome to try and identify genes that code for the crystals. It might then be possible to breed sea mice to produce tailor-made crystals for human use. They are also investigating how the components of the crystals unite to form nanotubes, and how those nanotubes assemble into other structures.

Source- precis of article at:,13026,1182736,00.html

933325.  Sat Aug 18, 2012 11:40 am Reply with quote

waw .. I do not believe it is the post that I read the long post, about 8 years ago .. but i still give thumbs-up because there are some things that are very beneficial to me like a bag or other interior ... :)


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