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A Super-Efficient Light Bulb 468

Chroniton writes with news of a Silicon Valley company, Luxim, that has developed a tiny, full-spectrum light bulb, based on a plasma of argon gas, that gives off as much light as a streetlight while using less power. The Tic Tac-sized bulb operates at temperatures up to 6000K and produces 140 lumens/watt, almost ten times as efficient as standard incandescent lamps, and twice the efficiency of high-end LEDs. The new bulbs also have a lifetime of 20,000 hours. There's no mention of mercury or other heavy metals, which pose a problem for compact fluorescents.
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A Super-Efficient Light Bulb

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  • by 93 Escort Wagon ( 326346 ) on Saturday March 22, 2008 @05:34PM (#22831916)
    I found it interesting that the tiny bulb - at least in the video - was still using 250 watts and internally generated a temperature of 6000K (no they weren't talking color temp; they were talking actual temp). Now that's certainly lower than the 400 watt conventional streetlight they compared it to; but there's no mention in the video about scalability or low-power use. So the submitter's comment about it having advantages over compact fluorescents may have no basis in fact.
  • Re:Commercial use (Score:5, Informative)

    by exploder ( 196936 ) on Saturday March 22, 2008 @05:37PM (#22831936) Homepage
    Temperature isn't the whole story. Regular tungsten-filament incandescent bulbs operate at about 3600K, but it's a tiny filament, and encased in glass, so it's not much of a hazard.

    A 6000K plasma may even be safer, depending on the density of the plasma.
  • Re:Commercial use (Score:5, Informative)

    by Cowclops ( 630818 ) on Saturday March 22, 2008 @05:40PM (#22831952)
    Heat and temperature are not the same thing. If it produces 140 lumens per watt, I believe that makes it something like 50% efficient (which is insanely high for lighting). That means a 100 watt lightbulb of this technology would turn 50 watts or so into heat, and 50 watts or so into light. A 100 watt incandescant is turning 85 watts into heat and 15 watts into light. So even if it runs at a higher temperature, its confined to a very small space.

    This isn't dangerous at all.
  • Re:Commercial use (Score:3, Informative)

    by exploder ( 196936 ) on Saturday March 22, 2008 @05:41PM (#22831968) Homepage
    Temperature is not heat. Once you've got a 6000K plasma (probably not all that costly in terms of energy due to low mass), the amount of energy it takes to maintain that temperature can be quite low. I'm sure the mechanism is very well-insulated thermally.
  • by JonTurner ( 178845 ) on Saturday March 22, 2008 @05:43PM (#22831980) Journal
    When they say "6000K temperature" they mean color temperature, not thermal. 6000K color temperature is a match for natural sunlight. []
    Provides a table of other light sources for comparison and a bit of discussion about color theory.

    Some examples of some common and competitive light sources color temperature and CRI values are:
    # Candle: 1700k 100 CRI
    # High Pressure Sodium: 2100k 25 CRI
    # Incandescent: 2700k 100 CRI
    # Tungsten Halogen: 3200k 95 CRI
    # *Solux Bulb: 4100k 98 CRI
    # Cool White: 4200k 62 CRI
    # *Ott-Lite(TM) Pro: 5000k 82 CRI
    # Clear Metal Halide: 5500k 60 CRI
    # *Verilux® "Natural Spectrum®": 5500k 82 CRI (also called HappyEyes® and Trucolite Phosphor Technology(TM))
    # Natural Sunlight: 5000-6000k 100 CRI
    # *BlueMax(TM): 5900k 96 CRI
    # Daylight Bulb: 6400k 80 CRI
    # *Sharper Image Bright as Day(TM) Lamp: 6400k 80 CRI (also called "wide-spectrum","daylight spectrum","natural spectrum")
    # *NextTen SunWhite® Lamp: 6400k 82 CRI
    # *Bell&Howell Sunlight Lamp: 6500k 80-85 CRI
    # *FirstStreet Balanced Spectrum®: 6500k 84 CRI

    *=Marketed as a "full spectrum" or similar to sunlight source
    but to answer your point, yes a six thousand degree F bulb would be impractical for home use. :)
  • by mcpkaaos ( 449561 ) on Saturday March 22, 2008 @05:44PM (#22831984)
    The "nasty police helicopters" link is no bueno. No clicking!
  • Re:Light pollution (Score:5, Informative)

    by pcruce ( 1248328 ) on Saturday March 22, 2008 @05:47PM (#22831998)
    I agree. The reason it hasn't killed professional ground based astronomy is that it is quite easy to subtract the very focused wavelength of sodium vapor streetlights from an image, as sodium vapor lamps are almost completely monochromatic. If we switched to these full spectrum lamps that would be much more difficult, probably meaning we would only be able to do astronomy in very remote areas or with orbiting observatories. That said, even as strong a proponent of astronomy as I am, the increased efficiency of these lights would probably make it worthwhile...
  • by Wolfrider ( 856 ) <> on Saturday March 22, 2008 @05:48PM (#22832008) Homepage Journal
    But isn't 20,000 hours only a little more than 2 years?

    365 * 24 == 8760

    20,000 / 8760 == 2.283

    Is that right, or am I way off?
  • by John Hasler ( 414242 ) on Saturday March 22, 2008 @05:50PM (#22832020) Homepage
    > Such high operating temperatures would not be acceptable for domestic use
    > - the risk of fire would simply be too great.

    Don't be silly. 6000K is the internal temperature of the gas. The filament in an incandescent lamp can reach 3000K. What matters is the external temperature, which is likely to be lower for a more efficient lamp.
  • by Anonymous Coward on Saturday March 22, 2008 @05:51PM (#22832026)
    WTFV (watch the .. video). The temperature they're talking about really is 6000K in heat.

    As other shave pointed out, this is not too much of a problem for household use as ordinary incandescents reach 3600 at the filament. You just need to encase it in a glass bulb.
  • Re:Light pollution (Score:5, Informative)

    by peragrin ( 659227 ) on Saturday March 22, 2008 @05:51PM (#22832030)
    it also affects drivers, and pilots as well. In some regions airports have pushed for local laws to limit light pollution going up into the sky as it interferes with planes landing. Spot lights can temporary blind drivers causing accidents.

    Light pollution isn't so much about astronomy but being able to see when it is dark out, because some idiot is lighting up his yard like fen way park. At night less is more. I can use 5 watt 12 volt bulbs and light up your house better than spotlights. more of the house will be lit with less random dark spaces, and more importantly less shadows in which people can hid.
  • by epilido ( 959870 ) * on Saturday March 22, 2008 @05:55PM (#22832070)
    Lights are not on all of the time. if less than 12 hours use which is likely than your calculations put the life at 5 years in a street light configuration.
  • by inKubus ( 199753 ) on Saturday March 22, 2008 @06:03PM (#22832116) Homepage Journal
    6000K? Who cares? The thing is, this bulb is generating about 10 times the lumens per watt of input power as a standard incandescent. That means that it is dissipating more energy in the form of light and less in the form of heat. Regardless of the internal temperature of the plasma, how "hot" the bulb gets is really a function of the actual dissipated energy. For instance, a spark of static electricity has an extremely high "temperature" but it doesn't burn you. Granted, some of that energy might be occuring in the infra-red range, but I doubt it will be any hotter than a normal bulb.

    Also, if you look at HPS (high-pressure sodium vapor) lamps, the orange ones they use for street lights, the vessel that produces the light is actually quite small. There is an internal tube (made of quartz, I think) that holds the sodium. For the first few minutes, the bulb appears blue because you are seeing an arc in the center of it. After the sodium boils and then turns into a plasma, it is in a higher energy state and starts throwing off photons.

    The only difference in this bulb is they are eliminating the electrodes and using a different plasma. They use a high frequency RF that's tuned to the resonate frequency of the gas. Sort of like a microwave does for water, but this is more focused. The gas resonates and becomes a plasma. Then it starts throwing off photons. Your efficiency is limited by how efficiently you can make your RF circuit and amplifier and how focused you can place the RF. I imagine they are quoting the theoretical efficiency but they probably haven't achieved it yet.
  • Re:Dual purpose? (Score:4, Informative)

    by maroberts ( 15852 ) on Saturday March 22, 2008 @06:05PM (#22832134) Homepage Journal
    Answer is (probably) you'd need more of them to heat your house than standard bulbs. This is more efficient at converting energy into light, so it actually produces less heat than a light bulb. It may get to 6000K, but only at a very small point, so the amount of heat produced is quite small. A big radiator full of hot water will be more effective in terms of heat output. A radiator has huge size but a lower output per unit volume, whereas this has a very small volume but a high temperature.

    It also says 6000K at its center; I'm not sure whether it transmits that heat to the casing or not.
  • full spectrum? (Score:5, Informative)

    by Councilor Hart ( 673770 ) on Saturday March 22, 2008 @06:09PM (#22832158)
    Full spectrum with an Ar plasma at 6000K ~= 0.5 eV? Yes, you can get a lot of light out of it and it looks white, but I wouldn't call it a full spectrum. There are mostly peaks in the region 900-1500 (I don't have a spectra right in front of me right now, so from memory). But I could be wrong of course.
  • by poopdeville ( 841677 ) on Saturday March 22, 2008 @06:14PM (#22832184)
    In light physics, temperature and color temperature are the same thing. Color temperature refers to the temperature at which an ideal black body radiator will emit such a spectrum. This unit is obviously a temperature.

    Moreover, this lamp appears to be a high bandwidth lamp -- "full spectrum" as they said. This implies that it does not depend on the absorbsion and emission characteristics of specific atoms. Lamps like these -- fluorescents, high efficiency sodium lamps, and the like -- emit light at discrete wavelengths. High bandwidth lamps depend on incandescence to produce light. Indeed, color temperature doesn't make sense for these kinds of lamps -- no black body radiator will emit discrete spectra. (There's a "corrected" color temperature unit for these lamps used in the lighting trade)

    The point is: these lamps get hot. They reach about 6000K.
  • by epilido ( 959870 ) * on Saturday March 22, 2008 @06:15PM (#22832190)
    per your link...... LED-based [] lighting is safer and far more efficient than the Luxim device. Hmm the efficiencies listed state 100 lumen's per watt the parent shows 140l/W seems like leds are not far more efficient. I realize that the article taht you linked doesn't have the most up to date stats on leds and that the recent led bulbs are better that the eiki link but not that much better.... And I am not sure where safer comes from
  • Re:Dual purpose? (Score:3, Informative)

    by Zaatxe ( 939368 ) on Saturday March 22, 2008 @06:21PM (#22832222)
    With an operating temperature of 6000k how many do I need to heat my house?

    That won't work, because the temperature it reaches has nothing to do with the amount of heat it emmits. Besides, if it's almost 10 times as efficient as ordinary bulbs, you would have 10 times as much light to get the same heat. You would get warm, but I doubt you would able to sleep with that much light.
  • Re:Commercial use (Score:4, Informative)

    by poopdeville ( 841677 ) on Saturday March 22, 2008 @06:25PM (#22832234)
    This is color temperature. Color temperature has absolutely nothing to do with the temperature that a bulb operates.

    Oh lord.

    What do you think color temperature is? It is the temperature at which an ideal black body radiator emits a given light spectrum. It most certainly has to do with the temperature at which an incandescent bulb operates. The hotter the bulb gets, the higher the color temperature. And moreover, the smaller the light emitter becomes, the closer color temperature and operating temperature become.

    In this case, it would be physically impossible for a light of any sort to give off that much energy and only consume the amount of electricity available to even a street light.

    Temperature isn't energy. Temperature is energy density. For a given amount of energy, the smaller the emitter is, the hotter it will be.

    My space heater uses 1500watts and requires I believe 12amps to operate and it would never be able to get anywhere near 6000k even if it were to ignite.

    And? The heat emitter is huge. Scale it down to about a 10th its size and run 1500W through it. It will glow a nice bright white before melting.
  • Re:full spectrum? (Score:4, Informative)

    by Councilor Hart ( 673770 ) on Saturday March 22, 2008 @06:32PM (#22832262)
    argh, I am so used to these numbers I don't pay attention to the units anymore.
    That is 900-1500 nm.
    Another few tidbits:
    Ar plasma: white
    Ar + H2 plasma: red
    Ar + O2 plasma: purple-like
    Ar + N2 plasma: greenish
    Ar + too much current through the copper cathodes: priceless... (lots of copper sparks actually)
  • by asc99c ( 938635 ) on Saturday March 22, 2008 @06:37PM (#22832296)
    1) It scales down a bit at least. I'm pretty they were marketing it last year for projector bulbs at around 150W. Not sure whether it scales further down than that.

    2) 6000K is very close to sunlight so yeah it's a nice warm sunny light - should in theory be nicer than incandescent light anyway.

    3) No - it's a noble gas (unreactive) and naturally present in the atmosphere, making up nearly 1% of it in fact.

    4 and 5) Dunno. I was just searching for the projector bulb version and couldn't find any actually for sale, which given that it was announced half a year ago isn't great going :(
  • Re:Commercial use (Score:3, Informative)

    by rs79 ( 71822 ) <> on Saturday March 22, 2008 @06:39PM (#22832306) Homepage
    Um, folks? All this 3000K and 6000K talk does not mean temperature, it's the color of the light. 5000K is white, or at least the color of equitorial sunlight at noon in the equator, 2700k is tellowish soft light, 7500K is the color of noon in Norway.

    It's the color of a body of iron at those temperatures in Kelvin. This has nothing to do with the temperature of the bulb, that is a 7500 degree Kelvin 4 foot fluorescent bulb may be 7500K *in color* but it's barely 80 degrees F in operation. Although degrees Kelvin measures heat like Celsius and Farenheight, it also means "color" becaise of the black body of iron thing.

    I'm guessing this lamp is hot but it aint in the thousands of degreesm kelvin or otherwise althouhg I'm quite sure it's a 6000K bulk or whatever.

    140 lumens per watt is good but not earth shattering - this is what (high pressure) sodium lamps do already - and are the most efficient bulbs mankind makes. So this is as good but no better than the best we have now. What is good about it is it's small, most plasma lamps aren't.

    I'd be interested in knowing what happens to the amount of light per watt as the bulb is made smaller and larger.

    Sadly TFV did bad^H^H^Hhorrible things to my machine and there was no FA to read but I'm sure if it's really feasable I'll hear about it soon enough. Not like with those sulfur microwave lamps from a few years back that had similar claims.

  • Re:Light pollution (Score:3, Informative)

    by tomhudson ( 43916 ) <barbara.hudson@[ ... m ['bar' in gap]> on Saturday March 22, 2008 @06:40PM (#22832314) Journal

    It's times like these that I wish we'd hurry our dumb asses up and build huge observatories on the dark side of the moon.

    The only "Dark Side of the Moon" I know of is from Pink Floyd. How do you plan to fit a huge observatory on a cd?

  • Black Body Radiation (Score:3, Informative)

    by sd.fhasldff ( 833645 ) on Saturday March 22, 2008 @06:41PM (#22832316)
    OK, so plasma is not very close to an ideal black body, but regardless you still get some wide spectrum emissions with a peak near that of a corresponding black body. In this case (6000 Kelvin), that's a pretty nice white.
  • Re:full spectrum? (Score:4, Informative)

    by Sycraft-fu ( 314770 ) on Saturday March 22, 2008 @06:41PM (#22832318)
    Full spectrum doesn't necessarily mean perfectly smooth. There are "full spectrum" CCFLs too. As far as I can tell it just means that the white is pretty neutral, and that the spectrum is close to, or 100%, covered. So while this light might not be totally smooth, if it covers 100% of the spectrum, it is full spectrum. Also, the peaks might be something that could be mitigated to some extent with a filter. There are incandescents that do this. The bulb has a bluish tint to it because there is a colour filter on the glass. The net effect is to give a more natural spectrum since incandescents are so heavy in the red-yellow area normally.
  • Re:Commercial use (Score:3, Informative)

    by Anonymous Coward on Saturday March 22, 2008 @06:50PM (#22832360)
    Actually, lighting is only about 1% of total electricity consumption. So switching bulbs to more efficient designs make sweet blue all difference in the greater scheme of things.

    Lighting at 8.8%. []

    Lighting at 22%. []

  • Re:Commercial use (Score:3, Informative)

    by JohnFluxx ( 413620 ) on Saturday March 22, 2008 @06:56PM (#22832408)
    The post that you are referring to talked about incandescent bulbs and the light bulb in the article. Both of those do operate at a temperature of several thousands of degrees, very close to the temperature color that it emits.
  • What the Spec says (Score:5, Informative)

    by peccary ( 161168 ) on Saturday March 22, 2008 @07:07PM (#22832466)
    According to the product specifications available from Luxim, the actual operating temperature of the surface of the light bulb must be actively cooled to below 850C, and it is recommended that the temperature remain above 650C.

    There must be two dozen posts here already blathering about 6000K and nobody bothered to go read the company's official documentation? Here's their website [], here are a whole bunch of specs and videos [], now go read something before speculating.

  • by DougBTX ( 1260312 ) on Saturday March 22, 2008 @07:15PM (#22832502)
    In this case, they really do mean 6000K. See: [] It sounds like this thing gives off a black body spectrum, and operates at the same temperature as the surface of the sun. The sun gives off (almost) a black body spectrum too, so they have similar colours. This is probably how your colour chart above is defined, and why you talk about "colour temperature" in the first place: it's the colour of a black body at that temperature.
  • Minor information (Score:5, Informative)

    by dr2chase ( 653338 ) on Saturday March 22, 2008 @07:16PM (#22832504) Homepage
    Latest LEDs available (now) go as high as about 90 lumens/watt (Luxeon Rebel, at 350mA, if properly heat sinked). I read, somewhere, that Nichia has demoed an LED at 130 lumens/watt.

    However, their light, much like the light of this light, looks an awful lot like the light from a welder. You have to be careful about the pursuit of the almighty lumen -- it's a human-tweaked measure, not a physical measure, and lights score best by dumping all of their light into green. We probably don't want our homes to be lit by exclusively green light.

    One thing to note is that there is wide spectrum (true 6000K, this new light), wide spectrum (white LEDs, a relatively smooth blob in the optical frequencies), and wide spectrum (a strategically chosen selection single frequencies, in fluorescent lights). This new bulb should produce very nice looking like, but it might benefit from some of the same phosphors used in white LEDs to down-convert the higher frequencies.

    Properly run LEDs are claimed to have lifetimes in the range of 70,000 to 100,000 hours of use, and are not affected by rapid cycling (in fact, the recommended method for dimming them is to switch them on and off very quickly).

  • Re:Light pollution (Score:5, Informative)

    by icebrain ( 944107 ) on Saturday March 22, 2008 @07:38PM (#22832632)

    It's times like these that I wish we'd hurry our dumb asses up and build huge observatories on the far side of the moon.
    Fixed that for you. Of course, the real benefit isn't for light pollution (though that's easy enough to take care of when there's no air), since no "side" of the moon is in perpetual darkness. You have about a 336-hour day.

    The real benefit is for radio astronomy. The far side always faces away from earth, which is a giant radio noise source, and the bulk of the moon itself blocks all the signal. It's really the only place where you won't get such interference (a few space probes notwithstanding).
  • Re:Light pollution (Score:5, Informative)

    by Original Replica ( 908688 ) on Saturday March 22, 2008 @07:46PM (#22832698) Journal
    If you had ever spent much time in the countryside, you would know how well you can see by moonlight. I've been out during a full moon on a clear night and been able to play soccer with my friends. Driving requires that we can see dozens to hundreds of yards ahead, so need brighter illumination. We can see just fine outside at night for walking speeds. During the vast majority of our evolution we didn't have artificial light, but we did just fine, we still can.
  • by rcb1974 ( 654474 ) on Saturday March 22, 2008 @08:15PM (#22832870) Homepage
    When I was a student at Cornell, I worked in the Department of Plasma Physics one summer. We got some money from a startup company to do some research on these same types of plasma lamps. I looked at the spectrum of the light these lamps using a spectrometer. Of particular interest to me was the spectrum during the time when the lamp was starting up. I discovered some spectral lines and was able to determine which elements were present inside the bulb (i.e. reverse engineering). I recall there was sulfur, argon, and trace amounts of a other noble gases like krypton. In any case, here are my thoughts on these bulbs.

    The benefits:
    1. Super efficient light (2x as efficient as LEDs)
    2. Gorgeous spectrum. Matches the spectrum of the sun VERY closely. Beautiful white light is emitted and it is extremely intense. I was instructed by my professor to not look directly at the bulb when it was powered on.

    The Drawbacks:
    1. The lamps take about 10 seconds to start up.
    2. After they are powered off, you have to wait about 2 minutes before you can turn them back on again. This is because certain elements inside the bulbs (like sulfur) need to cool down, solidify, and redeposited themselves back onto the interior walls of the quartz bulb.
    3. They must be mounted atop a very large (about 25cm x 25cm x 15cm) magnetron that generates microwaves.
    4. The bulb must be surrounded by a Faraday cage (in this case, a metal screen) so that the microwaves are confined to the area around the bulb only.
    5. The magnetron is bulky, heavy, and noisy
    6. The bulb itself gets VERY hot. They can be a fire hazard.

    They definately have some good applications, like for use in stadiums, airports, etc. However, I think there needs to be more research done to make them usable in homes and automobiles.
  • Re:Commercial use (Score:4, Informative)

    by forand ( 530402 ) on Saturday March 22, 2008 @08:19PM (#22832888) Homepage
    Generally what is discussed is black body emission (yes it sounds odd). You need to get a black body to these temperatures to emit the corresponding light. Now since TFA states that the light is full spectrum then it necessarily needs to be at around 6000K to "look" like 6000K. Lights that do not emit at full spectrum do not need to be at the the temperature but instead need to mimic it to our senses.
  • Temperature (Score:5, Informative)

    by kf6auf ( 719514 ) on Saturday March 22, 2008 @08:32PM (#22832934)
    For any blackbody emitter (incandescent light bulb or this fancy new plasma), the color temperature IS the temperature. It's only for things that don't emit like blackbody radiators (fluorescent and LED) where you have a different color temperature than temperature.
  • by Geoffrey.landis ( 926948 ) on Saturday March 22, 2008 @08:38PM (#22832966) Homepage

    In light physics, temperature and color temperature are the same thing.

    Correction, for a blackbody, in physics, temperature and color temperature are the same thing.

    For an object which is not emitting as a blackbody, "color temperature" means, basically, the temperature that a blackbody would have to be at in order to emit the same color of light, where "color of light" has mostly a lot to do with physics of perception, and not physics of light. For an object that's not a blackbody, "color temperature" is not the same as temperature.

  • Re:Commercial use (Score:3, Informative)

    by puppet10 ( 84610 ) on Saturday March 22, 2008 @09:08PM (#22833120)
    The color of the light is directly related to its temperature if you are generating the light by heating something up (rather than a fluorescent where you are using an atomic or molecular excitation).

    So in the case of an incandescent bulbs the temperature of the tungsten filament is close to the observed color temperature of the light as the filament is close to being a blackbody radiator (although the bulb itself will be cooler since it is not in direct contact with the filament producing the light).

    Since the person in the video explicitly states the full spectrum is daylight-like spectrum is due to the temperature of the plasma in the bulb being around 6000k it is likely (though the person describing in the video may be mistaken - however he is likely better briefed than you or I) that the light is generated from a heating process close to a blackbody radiator although again it is unlikely the bulb envelope itself would be at the 6000K temperature as the plasma would be contained in a small volume within the bulb.
  • by Jesus_666 ( 702802 ) on Saturday March 22, 2008 @09:09PM (#22833128)
    Neither your monitor nor a light bulb with colored plastic wrap are blackbody emitters. Your monitor relies on causing small elements to emit very specific wavelengths of light; having these elements close together allows for mixing. The light bulb emits light from a quite hot filament and then you selectively remove certain wavelengths with the plastic wrap.

    It kind of makes sense to assume that an incandescent light source is hot because, to quote the all-knowing Wikipedia, incandescence is the release of electromagnetic radiation, usually visible radiation, from a body due to its temperature. []
  • by stomv ( 80392 ) on Saturday March 22, 2008 @09:17PM (#22833182) Homepage
    but rather, because we have these rare pieces of real estate called sidewalks, and people who actually use them for walking.
  • Re:Commercial use (Score:3, Informative)

    by J.R. Random ( 801334 ) on Saturday March 22, 2008 @09:19PM (#22833194)

    Um folks, when you're talking about black body radiation the "color temperature" is the temperature. And the glowing object doesn't have to be iron. Glowing argon emits the same way. The video makes it clear that that bitty argon light is 6000 K at the core. I'm sure it's much cooler at the surface of the bulb. With a core temperature of 6000 K most of the energy will be emitted as visible light, not infrared, which of course is the point.

    Fluorescent lights do not produce light via black body radiation so their "color temperature" has nothing to do with their real temperature. Likewise with LEDs.

  • by Jah-Wren Ryel ( 80510 ) on Saturday March 22, 2008 @11:21PM (#22833638)

    because we have these rare pieces of real estate called sidewalks, and people who actually use them for walking.
    Which is often counter-productive because they kill situational awareness. Sure the people walking on the sidewalk can see the ground right in front of them just fine, but what they can't see is 3 feet off to the left or the right where a mugger is standing just beyond the edge of the light waiting for them.

    I'd rather they spent the money on better quality sidewalks and let our eyes do what they were made to do - adjust to the light.
  • by apoc.famine ( 621563 ) <apoc.famine@gmail . c om> on Saturday March 22, 2008 @11:37PM (#22833706) Journal
    As a former astronomer, that is patently obvious. However, humanity goes like moths to the lights. It is really hard to teach the average citizen that cutting the luminosity by 80% but tripling the number of lights will make an area much more safe. There is some bizarre connection between bright and safe, when "uniformly lit" would be far, far more safe, regardless of the brightness.

    I'm reminded of a time in my youth, when I was traveling by car with a group of friends. One road out of town has intense streetlights, spaced some distance apart. The darkness between them is amazing. As I blew down the road, definitely "under the speed limit" should any adult have asked, I came across a large, black dog, midway between two streetlights. I swerved across the road, onto the shoulder, and narrowly missed a mailbox and a tree. My friends behind me in another car had no idea what I was doing, until they also almost hit the dog.

    No matter how bright they make those streetlights, until there is *uniform* brightness, there will be danger. I wish I knew how to clearly point this out to people.
  • by gasmasher ( 750585 ) on Sunday March 23, 2008 @12:10AM (#22833846)
    It isn't that expensive. I built a hood for my 75 gallon reef and it has 350 Watts of compact fluorescent light using 2 Fulham Workhorse ballasts. The total cost of the hood was around $350 and the bulbs should be replaced once a year for about $200. That is over 4 watts/gallon and easily supports my cnidarians and clams. The bulb in the article is not suitable for a reef tank with corals, clams, or anemones since the temperature isn't in the 10K range but it should work great in a planted tank.
  • by PhireN ( 916388 ) on Sunday March 23, 2008 @12:46AM (#22834014)
    It managed to overload Firefox 3 beta with infinite popups. First time I've seen a popup in ages.
  • Re:Short answer.... (Score:4, Informative)

    by symbolset ( 646467 ) on Sunday March 23, 2008 @01:52AM (#22834380) Journal

    Apparently Sam is a debian developer of some major projects [].

    If you're interested, the links on the left at that page give some interesting depth of background. He has a long and interesting history.

    Be careful with this stuff. The above link goes to his server and they can be changed at any time. They appear to be harmless at the time I'm writing this though. Some of the content is NSFW.

    He's apparently a big deal [] in IT.

    It's possible his server's been owned, but if somebody did that, they did a remarkably convincing job of integrating the bad into the good.

    I'm torn here. Responsible geek reaches his dotage at the ripe old age of 30? Trolls have decided to reach over into illegal activity? Some combination of the above? I regret I lack the time and tools to look into it further.

    We'll just have to be more careful.

  • Re:Light pollution (Score:1, Informative)

    by Anonymous Coward on Sunday March 23, 2008 @04:30AM (#22834928)
    Two words: Pellet gun.
  • Re:Light pollution (Score:3, Informative)

    by Alioth ( 221270 ) <no@spam> on Sunday March 23, 2008 @06:12AM (#22835208) Journal
    Thing is they aren't more efficient than streetlights. Low pressure sodium, available for decades, is 180 lumens/watt; 40 lumens/watt better than these. If low pressure sodium streetlights are replaced by these it will *decrease* efficiency and *increase* pollution.

    Astronomers prefer low pressure sodium too since they can be easily filtered. Full spectrum lights will be the bane of astronomy.
  • Re:Light pollution (Score:5, Informative)

    by ivan256 ( 17499 ) on Sunday March 23, 2008 @10:51AM (#22836414)
    It's hard to be optimistic about LED efficiency improvements these days. The announcements of improvements made by manufacturers over the last few years have yet to make it to the market, and the units I've purchased in bulk typically don't match the ratings. The last project I built with high-efficiency LEDs required that I throw out about two thirds, and that I test every one individually. Of the ones that passed, several failed within the first 1000 hours of use.

    140 lumens per watt by 2012 would be nice, but I'll believe it when I see it.
  • Re:Short answer.... (Score:1, Informative)

    by Anonymous Coward on Sunday March 23, 2008 @12:33PM (#22836948)
    Nope, I can assure you that Sam is 100% responsible for this. has been hosting that content for several years now.

    The real suckers are those of you who didn't believe me when I warned you about Sam's association with GNAA, trolling, scat porn, and the like, before you elected him to Debian Project Leader.
  • Re:Light pollution (Score:3, Informative)

    by budgenator ( 254554 ) on Sunday March 23, 2008 @01:06PM (#22837148) Journal
    1. long days and long nights mean thermal equilibrium lasts for a long time on the equatorial regions,
    2. polar regions are always day/night so that's a constant
    3. Hubble seems to do ok without an atmosphere
    4. even ground based telescopes like my puny 6 incher need some time to equilibrate thermaly
  • Re:Light pollution (Score:3, Informative)

    by mspohr ( 589790 ) on Sunday March 23, 2008 @01:46PM (#22837410)
    I had a neighbor with an annoying spotlight. I put up a few common red reflectors which gave him a couple of red evil eyes pointing back to his house. Guess what?... the light went off (and stayed off).

God made the integers; all else is the work of Man. -- Kronecker