[HN Gopher] Livermore's centennial light, the world's longest-bu...
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Livermore's centennial light, the world's longest-burning light
bulb
Author : tentacleuno
Score : 39 points
Date : 2021-11-01 15:15 UTC (7 hours ago)
(HTM) web link (www.centennialbulb.org)
(TXT) w3m dump (www.centennialbulb.org)
| mattowen_uk wrote:
| As it's not directly explained on the link, I'll ask here...
| How/Why is it still burning?
|
| I have light bulbs in my house that blow after only a few months
| use, and normally only blow when I turn them on, if this bulb was
| power cycled, would it blow?
| devindotcom wrote:
| As I understand it the issue with ordinary incandescents is
| that the alternating heat and cold from being used eventually
| causes the glue attaching the glass to the metal part to crack,
| which lets air into the bulb (ordinarily a vacuum/inert gas).
| The next time you turn it on, the air causes the filament to
| burn, causing the characteristic flare-up and scorch.
| MisterTea wrote:
| Er, that glue only holds the glass bulb in the socket. The
| atmosphere contained within is completely glass sealed.
|
| What happens is the filament sputters away (like evaporation)
| and becomes thinner over time. It eventually becomes so thin
| it breaks from thermal shock when turned on. The dark spot on
| dead bulbs in the evaporated tungsten.
|
| Fun fact: In theater a blown bulb can ruin a production so
| some of the more critical lamps are dimmed instead of power
| cycled to avoid blowing a lamp.
| devindotcom wrote:
| Really? I was under the impression that the glass isn't a
| fully enclosed "bulb" so to speak, but is cut off at one
| end to accommodate the rest of the necessary hardware, and
| glue completes the seal. Perhaps you're right. I can't seem
| to find a diagram or anything that shows this, though.
| MisterTea wrote:
| If you examine a clear incandescent bulb, you will see
| that the support for the filament is hollow and has a
| tube inside extending down. This little "straw" is the
| point of connection for evacuation where the air is
| removed and then back-filled with argon. The argon coaxes
| the tungsten back onto the filament preventing rapid
| sputtering which would happen in a pure vacuum. After the
| argon the little tube is heated until it hits melting
| point and crimped off for a near perfect hermetic seal.
| The argon pressure is still well below atmosphere so the
| bulb is still considered under "vacuum" compared to
| atmosphere.
| xenadu02 wrote:
| The leads are inserted through a glob of hot glass, along
| with a glass tube. The bulb's open base is heated to make
| it soft, the blob containing the leads with attached
| filament are inserted, then the base is welded to the
| lead blob. Last the tube is used to evacuate the bulb
| and/or inject inert gasses. While under this vacuum the
| tube is melted and smashed closed, permanently sealing
| the bulb. Attachment of the base comes later.
| giantrobot wrote:
| Besides the other great answers, there's also survivorship
| bias. This bulb wasn't necessarily _designed_ to last a hundred
| years. It 's just an outlier that _has_ lasted that long. We
| wouldn 't give a shit about it had it burned out fifty years
| ago. We don't talk about other bulbs (today) that lasted fifty
| years even though that's an extremely impressive number itself.
| If the Internet was around fifty years ago we might have half a
| dozen webcams pointing to the "Half Century Bulbs" and being
| fascinated with them lasting fifty years and wondering if any
| will get to a hundred years.
| BitwiseFool wrote:
| The flip-side of it being the world's longest lasting light-
| bulb is that _every other_ light-bulb made alongside it has
| burnt out by now.
|
| Its longevity is most likely due to a unique confluence of
| factors, not simply because of a robust design produced
| before the concept of planned obsolesce, as is often alluded
| to whenever the subject is brought up. I also suspect its
| longevity is helped by all the delicate care and attention it
| has been given since people realized that it has been running
| for so long. It has a dedicated power supply, it is under-
| powered, and great care has been taken not to damage it.
| Normal lightbulbs never get such a luxury.
|
| It is certainly possible a newer lightbulb has already been
| produced that will burn for twice as long as the Centennial
| Light. We just won't live long enough to see it.
| jbay808 wrote:
| "Survivorship bias" is a favourite go-to for contrarians, but
| it's not a strong effect and when you see something
| surprising way out at the tail end of a distribution,
| attributing it to survivorship bias is a lost opportunity to
| learn something important. When something survives 2x longer
| than expected, it might be survivorship bias. When it
| survives 10x, 100x, or 1000x longer than expected, you should
| probably look closer and see what material or operational
| differences might be responsible, because there's going to be
| something worth learning.
|
| Even if what you learn is just that _any_ incandescent
| lightbulb can have a greatly extended life if you run it at
| below-spec brightness.
| giantrobot wrote:
| When you have an outlier like this bulb you can't make any
| good statistical judgements about it unless it was part of
| a controlled experiment.
|
| This bulb is a sample size of one. We might roughly know
| some details about its original construction and early
| operational life but not enough to really draw conclusions
| from. The only way to get more details about it will be a
| postmortem examination of its physical qualities.
|
| Due to its age we have little knowledge of its specific
| construction details. Were the factory specs followed
| exactly (or even recorded) or was some of the fabrication
| machinery tuned by the operator? Did this bulb end up with
| thicker than normal glass or filament? What was the
| mortality rate of other bulbs in its batch? Does the fire
| station have better (or worse) than typical wiring? Did it
| have bad wiring early in the bulb's life to unintentionally
| under-load it?
|
| Sometimes extreme outliers are just extreme outliers. A
| postmortem examination of the bulb might tell you it had a
| manufacturing _defect_ giving it thicker than typical
| filament that combined with babying it for the past 50
| years extended its life.
|
| Sorry it's not just being contrarian. Outliers are
| outliers. Just because something is an outlier in a
| distribution doesn't automatically mean there's some hidden
| truth of the universe to be revealed.
| kragen wrote:
| > _When something survives 2x longer than expected, it
| might be survivorship bias. When it survives 10x, 100x, or
| 1000x longer than expected, you should probably look
| closer_
|
| You're implicitly assuming a normal distribution or
| something like it, but it's easy for a lognormal
| distribution to span multiple orders of magnitude like
| that, and the Weibull distribution commonly used in
| reliability modeling for this kind of thing can also be
| heavy-tailed if _k_ > 1.
|
| A simple physical example of how this could arise would be
| if the filament diameter of a batch of bulbs was normally
| distributed spanning a factor of 2, resulting in filament
| resistances spanning a factor of 4, resulting in filament
| powers spanning that same factor of 4, resulting in
| filament powers per unit area of filament surface spanning
| a factor of 2 (since the thickest filaments have the lowest
| resistance and thus the highest power at a fixed voltage;
| it'd be 8x instead on a constant-current source), resulting
| in filament Stefan-Boltzmann temperatures varying by about
| 19% (1.19 is the fourth root of 2), which works out to a
| temperature difference of about 200 K for filament
| temperatures of about 1000 K. That's probably (handwaving
| here) enough temperature difference for about an order of
| magnitude difference in vapor pressure, which (handwaving
| wildly at this point) might mean an order of magnitude
| difference in filament evaporation rate.
|
| Also, typically there are hotspots in a filament where it's
| thinner than the rest, which evaporate more rapidly because
| they're hotter, which makes them get thinner faster, making
| them even hotter. So the dominating factor in filament
| lifetime (at a given voltage) might not be how thick it is
| but how smooth it is.
|
| So, you might find out something interesting. Or you might
| just find that this bulb had an unusually thick or smooth
| filament.
|
| (Carbon has 1000x higher vapor pressure than tungsten,
| though, which is relevant here:
| https://www.powerstream.com/vapor-pressure.htm.)
| jbay808 wrote:
| _> You 're implicitly assuming a normal distribution_
|
| I'm not really making that assumption. Instead, I'm
| pointing out that learning this particular bulb survived
| due to "unusually think or smooth filament compared with
| other bulbs" is indeed something interesting you can
| learn by inspecting the survivor, and that might be
| something you can apply for process quality improvement.
|
| Basically, I'm advocating the point of view that if you
| are trying to _improve_ lightbulb, or say, ball bearing
| quality (rather than just model it), then it 's useful to
| look beyond the fact that the Weibull distribution is
| long-tailed. A wide distribution is a reflection of
| ignorance and thus a learning opportunity; the long tails
| are still _caused by something_. Yes, from a given batch
| of ball bearings, some might last 10x or 100x longer than
| others under the same loading conditions. But if you put
| those super-long-lasting bearings under a microscope, you
| might observe real, important differences compared with
| others from the same batch. The balls might all be
| rounder or more identically-sized compared with their
| cousins. (You can do the inspection before the lifetime
| test if you want to be extra fair).
|
| But it's even more important when you don't expect a
| long-tailed distribution to begin with; for example, if
| you have a linear damage model. In this case, if you
| control for filament diameter, resistance, or brightness,
| and _still_ see that one bulb is a mysterious outlier,
| you might want to inspect the joints or run the gas in
| the bulb through an analyzer to see if there are any
| other surprises.
| thescriptkiddie wrote:
| Incandescent light bulbs have a trade-off between brightness
| and longevity. This bulb specifically appears to be running at
| a fraction of its original designed brightness.
|
| https://www.mercurynews.com/2011/02/03/tests-shine-light-on-...
| biggieshellz wrote:
| The carbon filament has gotten thin enough that it runs at a
| lower temperature and doesn't draw much current (or produce as
| many lumens), so it doesn't wear out as quickly.
| ars wrote:
| The simple reason is that it's not a light bulb, it's a heater.
|
| They are running it at much lower than specified voltage, so
| are generating mostly heat, and almost no light, so the
| filament is not very hot. It's glowing a dull red, not white.
|
| There is a quadratic relationship between temperature; and
| efficiency plus bulb life.
|
| You may have heard of the phoebus cartel - they specified a
| specific bulb life, which directly translates into a particular
| energy efficiency. There's nothing about the manufacture of the
| bulb that they casued to be worse, rather if the bulb lasts too
| long, you just up the temperature and make a more efficient
| bulb (uses less electricity).
|
| You can buy stage bulbs that last barely 10 hours, and run
| extremely hot, and also efficient, and for film that is the
| tradeoff they prefer (I guess they need a lot of light, and
| they don't really keep bulbs for long).
| dvh wrote:
| Every time you increase temperature by 10 degree, it shorten
| the lifespan of electric device by 50%. If you run device that
| was meant to run at 4600degC at 600degC, well you do the
| math...
| arcticbull wrote:
| Modern lightbulbs use thinner filaments that are substantially
| more efficient than the thick one used in this bulb, but they
| don't last as long. Further, this particular bulb never gets
| turn off and back on again which I'm led to believe causes
| wear.
|
| If it were turned off and back on it would likely be fine.
|
| Always a fun segue into the Phoebus Cartel [1] which pushed for
| shorter lifespans for bulbs - including by mandating thinner
| filaments. They did it to keep people on the treadmill but it
| was actually a substantial improvement in energy efficiency.
|
| [1] https://en.wikipedia.org/wiki/Phoebus_cartel
| edb_123 wrote:
| I also do think that the filament thickness has a lot to say
| for longevity. I have a "decor type" large warm glowing light
| bulb with a quite thick and long filament that's been on for
| hours daily and turned on and off multiple times daily for 10
| years now and counting. And yes, it is a real incandescent
| bulb, not LED :)
| CelestialTeapot wrote:
| The same game is still played today with LED bulbs (whether
| there's a cartel behind it or not, I do not pretend to
| know). See: https://www.youtube.com/watch?v=klaJqofCsu4
| kbutler wrote:
| Some factors: - low voltage (below spec)
| - constant on, instead of cycling - strong element
| - backup power - generally a protected environment
| longwave wrote:
| The bulb was accidentally off for nine hours in May 2013 due to
| a faulty UPS - originally installed to ensure the bulb would
| not go out in the case of a power failure - but fortunately it
| did not blow when power was restored.
| TruthWillHurt wrote:
| Before the invention of planned obsolescence...
| GuB-42 wrote:
| It also now has an efficiency of 0.05 lm/watt, 200 times less
| than a standard "planned obsolescence" tungsten filament light
| bulb and 3000 times less than a modern LED bulb.
|
| Planned obsolescence is a thing, but it is often a trade-off,
| not just companies being evil. By making things less durable,
| you can also make them cheaper, lighter, more efficient,... You
| also have to take technological progress into account. Your old
| dishwasher may last for 50+ years but it is heavy, loud, wastes
| water and electricity... So you may prefer a cheaper dishwasher
| that only lasts 10 years because you may want to change it
| later anyways because the energy savings of a new one can make
| keeping the old one not worth it.
|
| There are cases of planned obsolescence that are, in my
| opinion, inexcusable (looking at you smartphone manufacturers)
| but lightbulb longevity is a worthwhile trade-off.
| moab wrote:
| Obligatory on the topic of long-burning bulbs:
| https://www.tildedave.com/byron.html
| pokler wrote:
| It seems weird that Thomas Pynchon's name is nowhere to be
| found on this page or any other context about the source of
| this story (its from Gravity's Rainbow). There are also
| spelling errors.
| LeoPanthera wrote:
| See also: The Oxford Electric Bell, which has "rung" continuously
| since 1840 on the same set of batteries.
|
| https://en.wikipedia.org/wiki/Oxford_Electric_Bell
|
| I used to work in the same building as it. You can't actually
| hear it ringing, it's extremely quiet anyway and it's behind two
| layers of glass.
|
| I made a video of it ringing way back in 2011:
| https://youtu.be/1Dx1-f8xQio
| kragen wrote:
| I really appreciate your video. Thank you for posting it.
| kingcharles wrote:
| Clicked on YouTube link, realized we've met in real life. First
| time that's happened to me on HN.
| LeoPanthera wrote:
| I have no idea who you are. But hi. I no longer live in
| Oxford. Or the UK. :)
| dang wrote:
| Some past threads. Others?
|
| _Centennial Light_ -
| https://news.ycombinator.com/item?id=20427081 - July 2019 (20
| comments)
|
| _This Light Bulb has been burning for 110 Years straight_ -
| https://news.ycombinator.com/item?id=8749576 - Dec 2014 (1
| comment)
|
| _The Centennial Light, a bulb that 's reportedly been burning
| for 113 years_ - https://news.ycombinator.com/item?id=8353200 -
| Sept 2014 (29 comments)
|
| _The lightbulb that 's been burning for almost 110 years_ -
| https://news.ycombinator.com/item?id=2642483 - June 2011 (9
| comments)
| kej wrote:
| The Livermore bulb only has a small part, but this reminded me of
| the story _17776: What Football Will Look Like in the Future_
| [0]. It 's a fun science fiction story that is also a great
| example of web storytelling.
|
| [0] https://www.sbnation.com/a/17776-football
| kingcharles wrote:
| WTF. I DON'T EVEN.
|
| I have no idea what I just experienced. My PC fan spooled up to
| max speed when I clicked on the link and everything went all
| 2001 Entering The Monolith on me. I panicked, but I stuck with
| it.
| kibwen wrote:
| 17776 is the most important speculative fiction that I've read
| in the past decade. Don't be turned off by the eye-melting lo-
| fi hypermedia aesthetic, or the fact that the framing narrative
| is ostensibly about football, hosted on a sports website, and
| written by a sportswriter (all of whose work is brilliant, BTW,
| even if you don't follow sports). As absurdly silly as the
| premise is, it's quietly a thought-provoking treatment on how
| humans adapt to post-scarcity and utopia, and changed how I
| view the human relationship to modern video games.
|
| There's also (the first half of) a sequel, 20020:
| https://www.sbnation.com/secret-base/21410129/20020/
| th0ma5 wrote:
| Made in my hometown of Shelby, Ohio.
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(page generated 2021-11-01 23:02 UTC)