In X-Men: Days of Future Past I see several things about absence of metal that I am a bit skeptical about.

For example, Magneto is being held under the Pentagon and there should be no metal whatsoever hundreds of meters around him. But how do they provide lighting and electricity to power the security and comm systems down there? It is 1973, were there technologies to deliver energy without using metal back then?

Another example were Trask's sentinels, made of "modern polymers", without metal. What about their CPUs and other computing hardware?

So, the the question is, were there technologies back in 1973 that would allow the creation of metal-less underground prison cell and giant robots?

EDIT1: as an additional question, maybe the details about the technology are mentioned somewhere in the universe?

  • You can create an electrical circuit with water-filled glass tubes.
    – Valorum
    Apr 23, 2015 at 7:51
  • There are also elctrically conductive rubbers and polymers.
    – Joe L.
    Apr 23, 2015 at 11:56
  • Not all metals respond to Magnetism.
    – Oldcat
    May 22, 2015 at 18:05

3 Answers 3


Although it's in no way based on what we see in the film, this answer on Worldbuilding:SE would suggest that it's certainly possible to create viable electrical circuits without using metal. This could theoretically include lighting, audio communications and even surveillance equipment although video monitoring is probably a bit of a stretch.

These technologies (carbon wiring, arc-lighting, etc) were freely available in the 1970s so it's reasonable to assume that where there's a need, clever scientist chappies would have found a way.

  • While you (I assume) asked the question on Electrical Engineering, it seems to be considered off-topic there; it might be worth posting that question over on Worldbuilding, where the theoretical/hypothetical is (often) better received, and answers are (often) fastidiously accurate as regards the science/technology. Apr 26, 2015 at 23:45
  • @DavidThomas - Actually I'm pretty happy with the response I got there. Although some purists seem unhappy with the way I've couched the question, the mods and high-rep users have come through with some excellent suggestions. I may re-ask it on WB or I may not. Beyond answering the question to my own satisfaction (Is it possible with 70's tech? Yes it is) I'm not going to make it my life's work to find all the possible answers.
    – Valorum
    Apr 26, 2015 at 23:50
  • That's entirely fair, I wasn't intending to be critical of your chosen venue, just intending to provide a potential alternative. I'm not a user of Electrical Engineering, so I'm not particularly invested on a personal level beyond wanting the question to survive for future reference. Apr 26, 2015 at 23:54
  • @DavidThomas - If it gets zapped, I'll preserve it another way.
    – Valorum
    Apr 27, 2015 at 0:01

There are various ways to "pump" light around; fibre optics, light pipes (mirrors and straight runs; the mirror material can be nonmagnetic metals), lasers into diffuser material.

semi-conductor material, microwave excitation of gases in a silvered glass enclosure, radioactive excitation (think tritium).

As to anachronistic technologies, you have in the very same film examples of jet engine and robotics technologies we still do not possess, so it's a moot point.

Edit: (supposedly a history of fibre optics and precursors) http://www.jeffhecht.com/chron.html

States earliest laser 1960's http://opticalengineering.spiedigitallibrary.org/article.aspx?articleid=1096436


Assuming of course that Magneto is limited to manipulation of magnetic (ferrous) material, the minimal use of copper wiring needed for traditional lighting and glass breakage sensors would not be enough for Magneto to use. Notice that the guards even use plastic guns with what appears to be copper slugs.

For comparison, X2 showed that Magneto needs a certain amount of iron to be present to be able to feel it and manipulate it. The typical amount of iron in a human body did not cut it. So the plan involved injecting one of the guards with enough liquid iron so that Magneto could rip it out and form it into a usable weapon to escape.

In short, the cell was carefully constructed to have minimal if at all magnetically useful metal.

  • I think maybe you're referring to the "too much iron in your blood" scene in X-2.
    – phantom42
    May 22, 2015 at 17:49
  • Fixed @Phantom42
    – user16696
    May 22, 2015 at 18:52
  • They would not be using copper slugs in their guns
    – Valorum
    May 29, 2020 at 7:44

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