I have two binary pairs of planets in a planetary system. All of the planets are habitable, and similar in mass and composition to earth. Each pair is identical, or nearly so. The planets are tidally locked, and if you stand on the point closest to the other planet about 10% of the sky is obscured by it. One pair is closer to the sun, along an orbit somewhere in between earth's and venus's, while the other is between earth's and Mars's orbit. These planets orbit a sun just like ours.

How would this affect technological development in general? How would it affect the development of technology? Would worlds make areas for transmitting messages and information? You can see the other planet with your naked eye, with a weak telescope you can probably make out more details, and with powerful telescopes you can see the more distant binary pair.

Note - All planets have human intelligent life (if you can call humans intelligent) developing at similar rates. Also, the different planets would not have languages in common in the beginning.

  • $\begingroup$ Do both planets have intelligent life on them? Is one of these planets intended to have human beings on them? $\endgroup$
    – Avernium
    Feb 17, 2016 at 20:48
  • $\begingroup$ Oh! I forgot to say that! Yes @Avernium $\endgroup$ Feb 17, 2016 at 20:55
  • $\begingroup$ Do both planets have the same species of intelligent life? $\endgroup$
    – Avernium
    Feb 17, 2016 at 21:00
  • $\begingroup$ I just edited about five minutes ago. Take a look. $\endgroup$ Feb 17, 2016 at 21:04
  • 1
    $\begingroup$ With the edits that place life on both worlds, you might actually be a duplicate of this question. $\endgroup$
    – Avernium
    Feb 17, 2016 at 21:04

3 Answers 3


If this were the case for our society, we'd have a much larger space program.

As far as I can tell the primary reason more people are not interested in space travel today is that they simply can't see the point.

If we had an entire other habitable planet staring us in the face you can bet we'd be doing everything we could to get there and exploit its resources, claim its land, and get the glory of being the first.

  • $\begingroup$ I edited the question quite a bit, so your question only covers a minor portion now. Sorry. $\endgroup$ Feb 17, 2016 at 21:11

I have read suggestions that tidal locking of the Moon actually delayed the development of science, since the regular, unchanging patterns of features on the Moon were interpreted as reflections of the Earth from the perfectly mirrored surface to the Moon (as a celestial body free of the corrupting influence of matter, the Moon was considered perfect sphere of 100% reflectivity circling the Earth in a perfectly circular orbit...). A Moon which revolved around its own axis wold show an obviously different face all the time, changing how ancients thought of celestial bodies.

It is quite possible that the body in the sky could be misinterpreted as well (a perfect mirror reflecting the shape and events of this world), although that is less probable with a very active world overhead.

Since there is a visible world overhead, that will drive intense speculation as to its nature and providence, and it is very likely that science and technology will be driven towards exploring these worlds. The fallout of that will be advances in mathematics, map making, optics and perhaps building construction (as initially the people will think of building tall towers to the other world). While not exactly on topic, this will probably also lead to some pretty intense wars of religion/philosophy as various sides of the debate try to impose their views (and things like tower building will be quite resource intensive, so the "anti-tower"/world overhead is an illusion factions will have more of an incentive to stop the project).

One other thing which will drive technological development is the belief that there are other beings on the other world. This is a likely belief even without visible evidence of life on the other world (consider virtually nothing built by humans is visible to the naked eye beyond LEO,particularly during the day when no artificial lighting is on), Philosophers were writing about beings living on the Moon and planets as far back as "Micromégas", a 1752 short story by Voltaire, and "True History", written in the 2nd century AD by Lucian of Samosata could be considered the first SF tale ever.

This could lead to advances in communications technology as the people's of the various worlds attempt to communicate with each other, but also of military technology in response to the belief that the beings from other worlds might be hostile. An interesting side effect might be anti air weapons might be developed long before the actual development of powered flight as ancient civilizations attempt to protect themselves from essentially an angelic attack from space.

If sufficiently paranoid, long distance exploration could also be kicked off early in attempts to discover if the "angels" have already arrived on your world. Biological science might also be kick started in order to "prove" that particular species are either pure beings from this planet or alien beings from the other world (think of the early science of classification and the understanding of the relationships between species in the 1700's happening in Ancient Greece to get an idea).

  • $\begingroup$ Great answer! +1. It's worth noting that you probably meant providence, not provenience. $\endgroup$ Feb 18, 2016 at 12:48
  • $\begingroup$ Fixed that. Darned autocorrect. $\endgroup$
    – Thucydides
    Feb 19, 2016 at 0:41
  • $\begingroup$ Although it may be partially true, it might make them wonder about the planets' origin. $\endgroup$ Feb 19, 2016 at 0:45

For most of history there would be no difference other than how culture forms.

  • Philosophers would probably posit that life on these other planets was not only possible, but evident by their color and atmosphere.
  • Scientists might gain valuable insight into their own worlds weather patterns, atmospheric makeup, and other such facts based on their observation of the worlds' twin.
  • Religions might form deifying or vilifying the other world (Much like Earth's cultures deify/vilify the moon).

How would this affect technological development in general?

From the start it would definitely drive interest in optics, and efforts to increase lens effectiveness and magnification would have much more motivation. They'll need more and more powerful lenses and telescopes in order to gleam as much information about the other planet as they can through sight alone. This would reveal man-made structures which would betray the existence of intelligent life on the other planet. This would further increase interest and desire for knowledge and communication.

Then as soon as one of the worlds develop electricity, and the surface starts to light up, the worlds would get driven into a research and development frenzy, trying to catch up to their counterpart and out-do them. I wouldn't be surprised to see elaborate light shows to try and impress or communicate with the other world. Rate of discovery and interest in technological innovation would both increase drastically. The next important moment in history would then be when they both develop the capability of sending/receiving signals.

As soon as they're capable of communicating with each other, either through lasers, microwaves, radio, or what have you, that's when the political games will start.

Tensions will be high between the two planets. The leading governments will establish secure lines of communication in order to have political discussions involving the two planets relationship. Whether these talks go well or poorly depends on the personality and character of the delegates from each planet.

In an ideal, peaceful situation both worlds would aid the other and seek to develop interplanetary travel in order to establish trading routes, inter-world tourism, and cultural exchange.

If someone blunders or slights the other, there may be a rat race to develop interplanetary travel -- or interplanetary weapons -- in order to achieve military dominance and control of the planet-system.

Would worlds make areas for transmitting messages and information?

Like I mentioned in the previous section, governments would probably attempt to restrict communication between the worlds in order to limit any possible social or political blunders. As such there might be communication rooms set up in the capitol(s) in order to facilitate discussion (Like an audio-conferencing United Nations).

  • $\begingroup$ In addition to the wonderful answers by those who replied to this question $\endgroup$
    – Redmega
    Feb 17, 2016 at 23:40
  • $\begingroup$ Great answer, all though it will probably be obvious for a while before electric lighting, wouldn't it? After all telescopes powerful enough would probably be able to pick out large cities. $\endgroup$ Feb 18, 2016 at 1:21
  • $\begingroup$ Ah, didn't realize they were that close. Good point. I'll edit the answer after class to reflect that. I meant to include a blurb about optics but the subject of optics was pretty well covered in the other question. $\endgroup$
    – Redmega
    Feb 18, 2016 at 1:22
  • $\begingroup$ Telescopes and communication without the ability to travel might lead to some interesting "Radio Free America" situations with nations on one planet using flashes or light patterns to tell the other planet about all the lies their government is telling them. Or missionaries trying to convert people. $\endgroup$
    – Zan Lynx
    Feb 19, 2016 at 2:10

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