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Ask Slashdot: After We're Gone, the Last Electrical Device Still Working? 403

Leomania writes: After watching a post-apocalyptic Sci-Fi short on YouTube (there are quite a few) and then having our robot vacuum take off and start working the room, I just wondered what would be the last electric/electronic device still functioning if humans were suddenly gone. I don't mean sitting there with no power but would work if the power came back on; rather, something continuously powered, doing the task it was designed for. Are we talking a few years, decades, or far longer?
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Ask Slashdot: After We're Gone, the Last Electrical Device Still Working?

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  • by turkeydance ( 1266624 ) on Wednesday May 13, 2015 @05:15AM (#49679803)
    one perspective.
    • Exactly what I was going to say... the AI that exterminates mankind will keep working indefinitely.

  • satellites (Score:5, Insightful)

    by Anonymous Coward on Wednesday May 13, 2015 @05:19AM (#49679819)

    Probably satellites would last the longest, with maybe Pioneer or Voyager probes for however the RT batteries last.

    • by AmiMoJo ( 196126 ) <mojo@worl[ ]net ['d3.' in gap]> on Wednesday May 13, 2015 @05:35AM (#49679909) Homepage

      A Nokia 3310 will outlast them all.

      • Only if it's sitting on its charger... It only had a week's worth of battery. Which is massive by today's standards, but still.

        • by Lumpy ( 12016 )

          God I miss the days of good cellphones. My Nokia N82 was epic in battery life. Back when Nokia made the absolute best cellphones in the solar system.

          • There is no reason your phone couldn't last a week now. Just need a battery pack the size of a deck of cards attached to it.
      • Re:satellites (Score:5, Informative)

        by Antique Geekmeister ( 740220 ) on Wednesday May 13, 2015 @08:08AM (#49680483)

        The Volkswagen Beetle from the Woody Allen movie, "Sleeper"

                http://www.tin.org/bin/man.cgi... [tin.org]

        More realistically, some chemical batteries, such as good lead-acid batteries in cool, dry climates will retain a slight charge for years. But they all have a notable self-discharge rate of at least a few percent a month. The notable exception among battery technologies seems to be this:

                http://en.wikipedia.org/wiki/O... [wikipedia.org]

        That device has been running off its battery, at an extremely low rate, since 1840. The bell is much softer now, but it shows no signs of failing.

    • Re:satellites (Score:4, Informative)

      by hackertourist ( 2202674 ) <.ln.tensmx. .ta. .tsiruotrekcah.> on Wednesday May 13, 2015 @07:19AM (#49680225)

      The Voyager RTGs are decaying, NASA expects output power to drop below the point where it can keep a single instrument going around 2025.
      The Pioneers are already long past the point where they can't send a strong enough signal to be detected.
      The latest nuclear power plants for the US Navy have been designed to run without refueling for the life of the ship. That's 50 years for aircraft carriers, so the USS Gerald R Ford (CVN 78) is capable of functioning until 2065. Now I don't know how stable a nuclear power plant is when left on its own, but potentially this'll live much longer than the Voyagers.

      • One should be very wary of the distinction between "run without refueling" and "run without regular maintenance". Even assuming that the reactor's fuel would last, the ancillary equipment associated with the reactor's operation (coolant pumps and such) and electricity generation (steam turbines) certainly wouldn't be expected to operate unattended and unmaintained for months, let alone years.

        That said, the fifty-year planned lifespan of the Nimitz-class includes, if I'm not mistaken, a mid-life refuellin

        • Re:satellites (Score:5, Insightful)

          by dj245 ( 732906 ) on Wednesday May 13, 2015 @11:33AM (#49682129) Homepage

          One should be very wary of the distinction between "run without refueling" and "run without regular maintenance". Even assuming that the reactor's fuel would last, the ancillary equipment associated with the reactor's operation (coolant pumps and such) and electricity generation (steam turbines) certainly wouldn't be expected to operate unattended and unmaintained for months, let alone years.

          That said, the fifty-year planned lifespan of the Nimitz-class includes, if I'm not mistaken, a mid-life refuelling and complex overhaul (RCOH). To be fair, the reactor's fuel would likely last longer than the planned 20-25 years if the carrier weren't actively steaming--but I wouldn't trust the other parts to last anywhere near so long.

          As a steam turbine engineer, I am fairly confident that, given a well maintained system to start with, the first failure would probably be in a stuck steam control valve. Over time, oxides build up on the valve stem, which would cause it to become stuck at some point. This would probably take 3-6 years. When that happened, the instrumentation control loop (need more steam, open valve, need less steam, close valve) would have a hiccup since it would ask for more or less demand and the valve wouldn't move. Valves stuck-open have historically caused many turbine overspeeds and resulting disasters.

          Depending on exactly how the system was set up, the stuck steam valve should trigger the control system to automatically close a different valve, shutting down the plant. However, it is possible that it would result in a large kaboom as the turbine entered overspeed and the turbine blades liberated.

          As for the last electrical device operating, my money would be on a solar powered yard light. The quality of those devices is generally terrible but the law of averages suggests some of them have to be on the long tail of a MTBF curve.

          • ... as the turbine entered overspeed and the turbine blades liberated.

            See. It's not just software. Turbine blades want to be free too.

  • XKCD answered this (Score:5, Interesting)

    by slart42 ( 694765 ) on Wednesday May 13, 2015 @05:20AM (#49679833)

    A very similar question was in an XKCD "What If?", but only in the printed book version (which has a bunch of extra chapters compared to the blog): "What would be the last artificial light source to glow when all humans were gone".

    IIRC, the conclusion was that it would be status LEDs on space probes or radiation glow from buried nuclear waste.

    • Re: (Score:2, Funny)

      by Anonymous Coward

      Gnu Hurd build server??

    • Re: (Score:3, Insightful)

      by CheeseyDJ ( 800272 )

      IIRC, the conclusion was that it would be status LEDs on space probes or radiation glow from buried nuclear waste.

      Why would space probes have status LEDs? Think about it.

      • by someone1234 ( 830754 ) on Wednesday May 13, 2015 @06:23AM (#49680037)

        Unit testing before launch?

        • Before launch you have connector to which you connect a computer and you can do a self diagnose on the satellite using that connection to the on board system. There is no reason to dedicate leds and leds wiring for that especially that you will need to check for many fail conditions.
          • by necro81 ( 917438 ) on Wednesday May 13, 2015 @07:52AM (#49680363) Journal

            Before launch you have connector to which you connect a computer and you can do a self diagnose on the satellite using that connection to the on board system. There is no reason to dedicate leds and leds wiring for that especially that you will need to check for many fail conditions.

            Having spun a number of boards in my career, I can tell you that it is trivial to add an 0402 LED indicator, just as an indication that the 3.3 V logic rail is powered. And because it was easiest (via inertia) to keep it in than to cut it out (even as a do-not-populate instruction to the board house) that little LED stayed in the design, even though in production no one would ever see it.

            Given the complexity of most satellites, I would be deeply surprised if there wasn't at least one LED on one of those boards.

            • by TheCarp ( 96830 )

              > And because it was easiest (via inertia) to keep it in than to cut it out (even as a do-not-populate
              > instruction to the board house) that little LED stayed in the design, even though in production no one
              > would ever see it.

              And someday down the line, in a situation he never imagined, someone is going to see that LED and be glad it was there. Possibly after its been scrapped, rescued from the scrap heap, and repurposed to replace the fried control in someone's coffee maker....but appreciated none

              • "Hot damn, an LED! We can sell this and eat for a month! Too bad we don't have the technology to actually make these anymore...."

              • That's kind of an interesting point. Let's say 500 years from now humans have warp drive and can zip between stars. Should the Voyagers be collected* and placed in a museum? Should it be left alone as a historical "site?" One could visit it. Get the sense of what ancient man accomplished, sending this tiny thing so far from home. But that would be lost putting it on display at the Smithsonian.

                I argue a "traveling" museum should be built next to Voyager, sharing its journey. School kids could warp in on thei

            • by AikonMGB ( 1013995 ) on Wednesday May 13, 2015 @08:08AM (#49680485) Homepage

              We don't design LEDs into our own boards, and we explicitly remove them from COTS boards that we use. Generally speaking the diffusers on LEDs outgas, meaning a) they are depositing materials on your spacecraft surfaces (bad) and b) could result in a shorting risk (also bad). There may be space-grade LEDs that big-space (think Hubble, JWST, Voyagers, etc.) use but I would be surprised. There's simply no need.

              "Is it plugged in? Is it turned on? Is it on frequency?" solves about 99% of basic device connection issues. An LED will make one very short portion of that slightly shorter, and then only when testing on the bench, since you can't see it as soon as you box it up. As soon as you can talk to a device, you are able to run a long form functional test on it, exercising every part of the design and ensuring everything is working correctly. If it passes, you're good. If it fails, you pull the unit.

              For ground support equipment, yeah sure, throw an LED on every rail and switch output.

  • A nuclear power plant (and its control room)?
    • by Spazmania ( 174582 ) on Wednesday May 13, 2015 @06:49AM (#49680091) Homepage

      Nope. It would scram when the rest of the electric grid collapsed a few days in. The plant has to constantly output power. When the grid fails, the plant automatically goes into safe mode to avoid tearing apart the turbines. Diesel generators then start up to run the plant until grid power returns but they'd only last as long as the fuel.

      Nothing associated with the public electric grid would last long without humans present.

      • by Lumpy ( 12016 )

        The nuclear pile still puts out a decent amount of heat after scram, and there are thermocouples down there for emergency power.

    • by necro81 ( 917438 )

      A nuclear power plant (and its control room)?

      I would recommend reading The World Without Us, which examines what would happen to the relics of our civilization if we, humans, suddenly disappeared (i.e., not extinct via war or disease, but just hypothetically got raptured away). Nuclear power plants don't fare so well. In fact, without human attendants to control them, cleanly power them down, and then decommission the plant several decades later, there is every likelihood that some nuclear plants would

  • Satellites (Score:4, Insightful)

    by Gre7g ( 801284 ) <gre7g.lutermanNO@SPAMgmail.com> on Wednesday May 13, 2015 @05:20AM (#49679839) Homepage

    Solar-powered, geosynched satellites will keep going for a while.

    • What about them garden lamps that are solar powered? They charge during the day and give off light at night.

    • My Casio is up to year 8 on the original battery. If my corpse fell where there was plenty of sunshine but not so much dirt as to wash up and bury my wrist I could see it going quite some time more. It's good for 200 meters diving, it should handle exposure for a good long time.

  • WALL-E (Score:5, Funny)

    by ei4anb ( 625481 ) on Wednesday May 13, 2015 @05:22AM (#49679853)
    you should watch WALL-E next, while pondering that question
  • by captainpanic ( 1173915 ) on Wednesday May 13, 2015 @05:25AM (#49679865)

    1. Solar powered parking meters, obviously. Humans may be all gone, but you still gotta pay for your spot downtown.
    But seriously though, these are designed to be robust, and to keep working even if the solar panel gets dirty. I don't see any reason why it would fail at any time.

    2. The other one I can think of are (again, solar powered) satellites in higher orbits. But I am not sure how much damage the solar radiation does to those on the long run.

    3. Wouldn't it be sad if the last electric device to work is one of those crappy solar powered moving plants (made of plastic)?
    One of these: https://www.youtube.com/watch?... [youtube.com]

  • by Cutterman ( 789191 ) on Wednesday May 13, 2015 @05:26AM (#49679867)

    Ray Bradbury asked the same question in 1950.

    http://en.wikipedia.org/wiki/T... [wikipedia.org]

    The Cutter

  • by scsirob ( 246572 ) on Wednesday May 13, 2015 @05:26AM (#49679871)

    These puppies are way out there, running on neclear power. No-one to bug them, nothing to break them.

    • These puppies are way out there, running on neclear power. No-one to bug them, nothing to break them.

      Nothing?

      Because there are not millions of objects hurtling through our universe at any given moment, as we sit here and theorize what large object might have wiped out all life on this planet before?

      The universe is nothing but one big pinball machine. Luck runs out eventually.

    • NASA gives the thermoelectric generators on the Voyagers 10 more years" [nasa.gov].

    • by Lumpy ( 12016 )

      Xleggorp and Zullupt have been tagging that thing every time they make the Kessel run in less than 11 parsecs.

    • by necro81 ( 917438 )
      Given that New Horizons is several decades (Pu-238 half-lives) younger, I would place my bets on it.
  • by tempmpi ( 233132 ) on Wednesday May 13, 2015 @05:27AM (#49679879)

    They are just a piece of wire, often embedded in some kind of ceramic. Without power and stored at a place well protected from the enviroment it would likely last for 100,000 years or more.

    • by necro81 ( 917438 )

      They are just a piece of wire, often embedded in some kind of ceramic. Without power and stored at a place well protected from the enviroment it would likely last for 100,000 years or more.

      I think that the expected lifetime of Ohm's law is roughly the age of the universe.

  • Easy (Score:2, Funny)

    by mwvdlee ( 775178 )

    The last electrical device after humanity ends will be the deathray which the aliens used to blast humanity out of existance.

  • by Chrisq ( 894406 ) on Wednesday May 13, 2015 @05:36AM (#49679915)
    The Oxford Electric Bell [wikipedia.org] has been running since 1840 and will probably carry on for a long time yet
  • by lkcl ( 517947 ) <lkcl@lkcl.net> on Wednesday May 13, 2015 @05:37AM (#49679917) Homepage

    andrew trigdell told me an amazing story back in 1999 about how he helped install Linux 0.99 on a solar-powered data collection computer in antarctica. Linux 0.99 was known to be highly stable, hence why it was chosen. it has a 56k modem which is enough to get the data back, and to check (very slowly) that it's still operational. so i think anything that's designed for long-term with those kinds of harsh remote and inaccessible conditions in mind, powered off of sustainable independent power, would be a good candidate for a device that would still be functioning even decades later.

    • by necro81 ( 917438 )

      so i think anything that's designed for long-term with those kinds of harsh remote and inaccessible conditions in mind, powered off of sustainable independent power, would be a good candidate for a device that would still be functioning even decades later.

      It's design is probably robust for decades, but anything out on the ice that sits still for more than a few years is destined to get buried in snow, solar panels and all.

  • Unless.... You expect a targeted strike where the only survivors are liberal art majors. Spin some magnets in some copper wire you get electricity. You can spin it with a water wheel, wind turbine, combustion engine, or steam power.

    You reverse the process and you can make a motor.
    Place some resistance you get heat and light. ...
    This dystopia future just isn't practical unless there is some lead time where science and engineering has been some how removed from our cultures.

  • Sounds like a question for Randall's "What If" series.

    Fascinating question though. I should imagine one of the voyager probes perhaps, or a solar powered beacon on a hill somewhere. A lot of stuff on Earth is very dependent on regular maintenance so I wouldn't imagine much stuff still working fifty years from the hypothetical extinction event.

  • Whatever it is, I think it will be inside a mountain. Maybe there should be an digital computer version of the 10,000 year clock [longnow.org] (mechanical not electrical) or something like the Svalbard Global Seed Vault [regjeringen.no].
  • by Coisiche ( 2000870 ) on Wednesday May 13, 2015 @06:09AM (#49680003)

    It's actually on an adjacent planet rather than Earth, but Opportunity seems like it will just keep going.

    xkcd joke [xkcd.com] about it.

  • by Anonymous Coward

    The little LED on my pink Floyd pulse album will still be flashing long after we are all gone.

  • Ironically?

    Given the way things are going, probably the Opportunity Mars Rover...

  • I doubt the ones that immediately occur to me will be the winners. However, there are smoke detectors guaranteed to work for over a decade, and there is a pacemaker with a minimum lifespan of 14 years. Some digital watches are also 10+ years. Tadiran batteries are supposedly good for 40 years in some applications (remote monitoring devices?)
  • It has been ringing continuously since 1840, and will probably continue for a long time.

    Read all about it here: http://www.atlasobscura.com/pl... [atlasobscura.com]

  • The power goes out permanently about 15 minutes after human input stops. That is the planning interval in the large electrical grids. No humans results in emergency shutdown of all power-plants a few minutes later and that is it.

  • I would assume it would be a simple device connected to a fully solar electric living space. If the solar panels and tech behind them keep functioning, the simplest of devices (maybe even a phone connected to an outlet) would have the most longevity.
  • The Wikipedia [slashdot.org] explains:

    The Oxford Electric Bell or Clarendon Dry Pile is an experimental electric bell that was set up in 1840 and which has run almost continuously ever since, apart from occasional short interruptions caused by high humidity.

    [...] The Oxford Electric Bell does not demonstrate perpetual motion. The bell will eventually stop when the dry piles have distributed their charges equally if the clapper does not wear out first.

  • The power output of RTGs declines over time, but according to Wikipedia Americium-241 has a half-life of 432 years and is an experimental replacement/alternative to Pu-238 RTGs.

    Since shielding and weight requirements are a non-factor for terrestrial RTGs, it wouldn't surprise me if there was some secret bunker someplace with a huge (1-2kW) RTG in place as a kind of emergency power source capable of powering a control system or something to bring up other power systems.

  • Walt Disney's head freezer is designed to keep running indefinitely.
  • Kind of mundane, but they're built to get installed in the middle of nowhere and keep working.

  • by moeinvt ( 851793 ) on Wednesday May 13, 2015 @08:08AM (#49680481)

    With moderate use, those things last forever.

  • A wind turbine or water turbine could continue for decades. Since part of the power generated is fed back to coils within the turbine they both use and create electricity. I do wonder how much of a windmill farm can survive one good tornado.
  • A solar powered electric fence charger is designed for neglect. The fence itself will be useless, weeds will ground it fairly quickly, and anybody who maintains them knows a fence won't last a year unmaintained, but the solar powered charger will keep ticking as long as the battery lasts, and will probably keep trying even after the battery fails. The cheap little solar powered yard lights also should keep working for quite a while, at least the ones that aren't DOA when they are purchased.

    But all devices

  • and protein from the sea.

    I am 'box' !

  • The last device still working definitely won't be anything made by Apple. The battery life in Apple devices is abysmal.
  • RTGs in lighthouses (Score:4, Interesting)

    by Phronesis ( 175966 ) on Wednesday May 13, 2015 @09:58AM (#49681297)
    The former Soviet Union built hundreds of automated lighthouses in remote locations powered by radioisotope thermoelectric generators. Those use 90Sr, which has a half-life of 30 years so they can go for many decades. They were installed in the 1970s-90s, so most of them are around one half-life out. They could well continue operating for several decades, but some small solar-powered devices might well outlast them if they aren't damaged too badly by weather over the years.

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