Inspired by a brief comment converstaion found here.

I would like to investigate the design and development of an alien species whose technological development did not include an understanding of light. Let us assume that the species is entirely blind, and only has the capacity to interact with their surroundings through other senses: sound, smell, pressure, thermal, taste, etc.

For them, they would never "see" light and would (ostensibly) develop without an interest in light. There would never be a moment when they look up and see stars and be inspired by the idea, "what's out there?" However, through audial experiments they could develop the idea that "there's nothing above me that I can detect... I wonder what's up there?"

They would also not devleop visually-oriented writing, but would need to rely on audio or braille for recording knowledge. I'm willing to accept without proof the idea that they can achieve our own skills in handwriting in ways that do not require eyesight.

Remember, though, no dependency on light. No development of radar, radio, light bulbs, microwave ovens, etc.

The goal is to land on their moon. Please assume similar challenges to NASA in the early 60s.

My goal is to establish a plausible explanation for how an alien species could attain space flight without a comprehension of light.

Question: Is it possible for a species (in this case blind) to develop the technology necessary to land on their own moon without a comprehension of light?

How I'll judge the best answer

  1. "It's impossible" is a legitimate answer, but it must be backed up with a lot more than a sentence or two of reasoning demonstrating why a moon shot is impossible without an understanding of light. You can't just claim it (no lazy answers, please!) you need to demonstrate how an understanding of light is unavoidable.

  2. If it can be done, an answer must have at least three examples of how interrelated technology could be accomplished without an understanding of light. For example: how to achieve the same process of doping semiconductors without the use of optical photolithography.

  3. If it can be done, an answer must consider all the major components of basic spaceflight: control, propulsion, life support, data aquisition (tough), and communication (very tough).

  4. I am willing to allow any design of the aliens so long as (a) they are utterly incapable of naturally detecting light and (b) they are not godlike. My voice can't carry to the moon, neither can an alien's telepathy. The alien characteristics you're depending on to circumvent the need for technological enhancements must be reasonably believable as a fact of natural adaptation/evolution and not simply a superpowered band-aid.

Finally: A reminder about what "Primarily Opinion-Based" (POB) means at Worldbuilding.SE

Stack exchange defines POB as:

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.

Regrettably, we can't change this text, but if you believe in it, then no question about magic can be asked because no answerer has facts, references, or specific expertise to draw from.[citation needed] Consequently, here at WB.SE we've had to reverse the meaning.

POB means the OP is responsible for providing enough information to reasonably judge which answer will be best. The OP cannot select a best answer simply as a matter of the OP's opinion. Thus, if the OP provides background about his/her magic system such that answers can be judged against it, then it is inappropriate to close the question as POB.

Given this explanation, if you believe my conditions for the best answer are insufficient to judge which answer is best, please let me know and I will further scope the question. After all, we're here to have fun with fiction, right?

  • $\begingroup$ Without the ability to comprehend light (or any other electromagnetic radiation), or without the ability to perceive it directly? $\endgroup$
    – Alexander
    Jul 18, 2018 at 0:23
  • $\begingroup$ @Alexander, You've brought up a good distinction. With the intelligence to supposedly get to their moon, they have the intellectual capacity to comprehend light, but do they nonetheless? Can you think of a way that they could comprehend light without ever having experienced it? $\endgroup$
    – JBH
    Jul 18, 2018 at 3:02
  • $\begingroup$ If their senses are as good as blind man's, and their world has open sky, they would quickly understand the concept of solar radiation. However, moving from this concept to creating tactile imaging may be impossibly difficult advancement. $\endgroup$
    – Alexander
    Jul 18, 2018 at 6:51
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    $\begingroup$ Following on from Alexander, they will be able to "feel" heat radiated via infrared light from hot objects, in the same way we can. We don't use our eyes for that. Whilst it's an even more limited experience into the spectrum than ours, they'll know it exists and with enough experimentation will discover the rest of it. At that point they could build sensors to translate their sky into a medium they can perceive, and produce radio and other wireless communication. $\endgroup$
    – Kyyshak
    Jul 18, 2018 at 10:00

2 Answers 2


I would find it hard to believe that they would even be aware of their moon without light. Sound, pressure, etc. require a medium to travel through. Because space is a vacuum, none of those would be able to indicate the presence of their moon. If the aliens determined that there was a moon, it would be through the gravitational effects, e.g. tides. But even from there things are difficult.

The modern theory of gravity was developed in large part due to astronomical observations, which require light. While there have been some experiments on earth, gravity requires such massive objects to be noticeable that it is unlikely that they would be able to work out that the tides are a result of a massive object in orbit. It would be basically impossible for them to characterize that large object. They would not know it's shape or size. Unless they have some amazing scientists, (In my opinion, well beyond anything Earth has ever seen) they likely would not even know its mass.

However, if they were able to work out the law of gravity, and trusted their science enough to determine orbital mechanics, and made some opportunistic assumptions, they might be able to make a pilotable spacecraft to their moon. It would be incredibly hard, however. First, they would have no communications. This especially complicates things because it means that all probes and test spacecraft would have to return in one piece in order for there to be any useful information (No learning from mistakes). They would have to navigate by gravity and perhaps the magnetic field of their planet. If their math is amazingly accurate, I think this could be done with very accurate accelerometers. Landing would be nearly impossible, because they wouldn't know the radius of the moon. The gravitational field of a solid sphere depends only on its mass, not on its size.

There are so many things that can go wrong in this trip, that it almost certainly won't happen. Most of their knowledge of where they are and thus, how they need to fly the spacecraft would be calculated from their readings and controls. If the sensors are ever so slightly off (I don't know how much), they won't be able to navigate. Ditto if any of their equations or physical constants are off. Crashing into the surface of the moon would be a very serious possibility. There is also the fact that they wouldn't know how fast the moon is rotating, and so they may hit the surface moving a couple thousand miles per hour sideways relative to it.

I'll finish by stating that it is unlikely that this species would have such a huge desire to visit the moon. Without telescopes and such, they would have no idea if there is anything of worth. It would be incredibly risky. It would take an effort dwarfing all Earth space programs. It would require genius Earth has never seen. It might just be possible, but I don't think it would ever happen.

Edit: I think that it would be impossible for a species to reach this level of scientific and engineering achievement without discovering light. All of the problems that I detailed above are much more abstract, less interesting, and less pertinent than ones that would lead to the discovery, and from there, the manipulation of light and other EM waves. Why is it hotter during the day? How do plants get energy? Why don't they grow well indoors? Why do oscillations in circuits sometimes cause similar oscillations in other, disconnected circuits? Why does heat transfer from hot objects in ways that can't be fully explained by convection and conduction? A species that lacks the curiosity to ask these questions or lacks the intelligence to answer them would not be willing and able to do what it needed to reach the moon.

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    $\begingroup$ +1 just for points in edit - basic observation of the immediate environment will lead to knowledge of light. $\endgroup$ Jul 18, 2018 at 4:10
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    $\begingroup$ The most likely scenario would probably actually be the nightside of a hot, tidelocked world with a somewhat thick atmosphere. So there's no day and all the "plants" are really fungi. $\endgroup$
    – majestas32
    Jul 18, 2018 at 16:11
  • $\begingroup$ @Majestas32 That would make the situation more likely, but still not entirely believable. For example, landing on the moon would certainly require some sort of computers and other electronics, and they would run up against EM interference at some point developing those. $\endgroup$ Jul 18, 2018 at 17:58
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    $\begingroup$ Yes. They will have to somehow discover EM radiation $\endgroup$
    – majestas32
    Jul 18, 2018 at 17:59

It's impossible.

Being blind isn't the problem. It's the ban on interacting with the entire electromagnetic spectrum. We can't see radio waves but we can still use them.

By banning (unreasonable I feel), the race has no means of communication through a vacuum. This means you can't monitor probes unless the probes return and the probes are virtually blind in space. The only way to detect something is to crash into it which isn't an ideal method for space exploration.

  • $\begingroup$ Before I edit the question (because I agree that it's unreasonable, but another user suggested it's unreasonable to assume that aliens who came to Earth would automatically know how to deal with radio waves), let me ask the question: Can you think of no method at all other than photonic to communicate over distance? It was once believed Tachyons (those mystical little critters) all jumped state at the same time throughout the universe. Has that been discredited? Is there nothing else we can possibly imagine? $\endgroup$
    – JBH
    Jul 17, 2018 at 23:53
  • $\begingroup$ Gravity waves maybe? If they could detect those little bad boys maybe you have a chance. Otherwise I agree, removing all parts of the electromagnetic spectrum is a little strict. Not to mention, testing rockets would be extremely difficult without this too... $\endgroup$
    – Jonnyboy
    Jul 18, 2018 at 7:32
  • $\begingroup$ IR radiation is how spaceships don't approach the temperature of their engines. If there is a full ban on EM that seems like more of a killer than being out of communication or even direction finding. $\endgroup$
    – user25818
    Jul 18, 2018 at 15:00

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