I'm currently exploring a setting where humans have managed to create traversable wormholes with one critical flaw - something in the wormhole both kills multi-cellular life and destroys electronic systems. The exact cause is unknown, the probes sent in are otherwise undamaged and even a mechanical pencil left in a maintenance hatch survived the trip unscathed.

(If it helps I'm leaning towards the idea that while inside a wormhole everything develops nigh infinite magnetic permeability, erasing all electrical and electrochemical data)

It was this mechanical pencil that inspired the idea of building a probe that utilised a mechanical computer rather than an electronic one. My mind immediately went 'steampunk' but steampunk stories are 'steampunk stories' which was not the intention when exploring this concept (though I'm more than happy to borrow the technology, if not the themes). Not to mention otherwise the tech level is set to today, it's more a revival of technology rather than an alternate path of technological development.

So my question is this, are there any examples of what amounts to a modern version of Babbage's Analytical Engine available today?

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    $\begingroup$ If you are thinking that it erases data rather than actually destroys components, could you instead use an analogue computer where the probe's logic and instructions are a physical part of its construction? $\endgroup$ Commented Aug 24, 2015 at 13:58
  • $\begingroup$ How would you know the pencil worked? You never get a probe back to analyze it, to figure out why they never return. $\endgroup$
    – JDługosz
    Commented Feb 17, 2016 at 3:30

4 Answers 4


You can make a computer out of almost anything though how long such a computer can run and how complex the programs on it can be vary. You can make computers out of falling dominos,knex or billiard balls if you're so inclined though they can only run very simple, very short programs.

For more serious computers gears are a good choice but you can also use optical computers, depending on the rules about what breaks you may be able to use rod logic computers,DNA computers, droplet computer or chemical computing.

Computers can be built to use fluidics instead of electronics.

In fact depending on how your computers break you could even have something like a simple fluidics computer which re-writes the magnetic storage of a more complex electronic computer which can then read from some more-durable non-electronic but dense storage medium.

Computer science is no more about actual specific computers than astronomy is about telescopes, you can build something to do computing out of almost anything if you're determined enough.

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    $\begingroup$ You can also make a computer out of rocks. $\endgroup$
    – Frostfyre
    Commented Aug 24, 2015 at 12:48
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    $\begingroup$ I like the idea of an unaffected but slower technology being used to rewrite and reboot the faster conventional electronics on the other side. Neat. $\endgroup$ Commented Aug 24, 2015 at 14:03
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    $\begingroup$ @Whelkaholism That's not so far off what actually happens in older normal desktop computers. The BIOS (basic input/output system) is a little bit like a miniature computer which knows how to start up the rest of the system. If your CMOS battery died your computer could no longer boot. $\endgroup$
    – Murphy
    Commented Aug 24, 2015 at 14:18
  • $\begingroup$ Indeed, but it would be FAR COOLER if the BIOS was a tiny box of gears, wouldn't it? :) Or better still a full on tiny Heath Robinson device. $\endgroup$ Commented Aug 24, 2015 at 14:53
  • $\begingroup$ Or you could make it out of magma and orthoclase!! dwarffortresswiki.org/index.php/v0.31:Computing $\endgroup$
    – Nanban Jim
    Commented Sep 25, 2015 at 23:56

In this case you probably wouldn't want a full computer. Far too complex. Some thing more like a very fancy clock work toy would be easier.

Your description of the worm hole makes it sound like old film would work as a recording media.

A simple probe could be a camera with a simple mechanical timer and a spring to "jump" the camera back through the worm hole.

Take a look at some of the complex clocks and especially for your interest the chimes and alarms that have been made over the years.


The ultimate Babbage machine was described by K Eric Drexler in his 1987 book "Engines of Creation". This was a "rod logic" device about the size of a bacterium, and Drexler talks about it here: http://www.halcyon.com/nanojbl/NanoConProc/nanocon2.html

to give you an idea of where Drexler thought this could go:

  1. Computers from Molecular Mechanical Components These computing devices are smaller than the transistors that were commonly in use in computers a couple of years ago by a factor of 104 in linear dimension, which means 1012 in volume. Thus a device of the capability of a single chip microprocessor, like the Z80 or Motorola 68000 made with 3 micron technology, could be put into a volume of 1/1000th of a cubic micron.

For random access memory, you should get nanosecond access times with 5 cubic nanometers per bit, or allowing for overhead, a density of about 1020 bits per cubic centimeter. That's more information in a cubic centimeter than people have written down since they started making marks on papyrus.

Tape memory gives you another factor of 100 in memory density. Bits would be stored by the presence of a bulky or less bulky side group on a polymer chain, such as polyethylene. To read the tape, you would mechanically probe it to find out how bulky the side group was. The write operation would involve chemical transformation. A reasonable length for such a tape is several microns; a reasonable spooling speed is like a meter per second. To get from one end of the tape to the other is thus a matter of microseconds. We're talking here about tape systems that are far faster than present day hard drives.

Estimates of power dissipation are relatively fuzzy. Making a gigahertz clock assumption and assuming a dissipation of 50kT per bit of a 32-bit word per cycle, we're talking of power dissipation in nanowatts. For a single device in good thermal contact with its environment that's a temperature rise of less than a thousandth of a degree Kelvin.

Thus a large computer can be small on the scale of a mammalian cell, giving some plausibility if you also assume some other hardware and a lot of software development, to the notion of cell repair systems. Also, yesterday I estimated the computational capacity that you could get in one cubic centimeter using this crude mechanical technology - more computational power in a desk top than exists in the world today.

There are a number of papers that discuss this and related topics. If you write to the Foresight Institute [Box 61058, Palo Alto, CA 94306] and send \$5, you can get a packet of papers that describes these things in more technical detail. For a donation of \$25, you can subscribe to the Foresight Institute newsletter "Foresight Update."

[For more up-to-date information, see the Foresight Institute home page. See also Chapter 12 of Nanosystems.]

So if you have the technology to make wormholes, I suspect making bacterium sized supercomputers wouldn't be a really big deal either. If such a device can be made "self aware" is a different question altogether.


(If it helps I'm leaning towards the idea that while inside a wormhole everything develops nigh infinite magnetic permeability, erasing all electrical and electrochemical data)

If that's the case, then have mechanical energy and data storage, but electronic logic.

Punch cards are mechanical, and should survive the wormhole just fine. Heck, CDs are technically mechanical storage too. Those ones-and-zeros are stored as little bumps on the surface of the disc.

Mechanical energy storage is easy. Wind-up spring. Us that to unfurl solar panels, and have them bootstrap the rest of the probe.


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