I came to SE WB while I was researching about space radiators for my sci-fi. I don't remember where exactly I found an answer to my question (Maybe? Idr) but I stunned with this site. You all looks like amazing.

I'm trying make this story as accurate as possible, start it years ago as way to teach some simple concepts to my children and the thing grow up since then:

In the year 2240 Humankind is in a time of reasonable peace and prosperity, the last giant calamity was depression in 2030-2050. After it, our species developed fusion nuclear reactors, organized political institutions in city-states and an unified global Parliament, built space elevators and a geostationary ring like the sequence in final chapter of The Fountains of Paradise in c. 2100. Then they moved all industry to orbit, built efficient space stations by the ring, similar with O'Neill cylinders, inhabited like small towns. Some of those stations release from the ring after disagreements with Earth government and call themselves as Wanderers.

Plans to terraform and colonize Mars and Venus are put in action and the Martian colonization starts before they even complete a decent atmosphere. Between years 2120 and 2240 the red planet population is raised from 50 persons to 960 million inhabitants. They built a geostationary ring and space elevators near/on Mars too.

Spaceships still use fission nuclear reactors since miniaturization of fusion reactors has made slow progress. With promising new fusion reactors comes the development of the constant acceleration drives. By 2240, space mining has cleared almost all asteroids in near earth orbit. Wanderers move more and more away from Earth and after Mars and are base themselves in the asteroid belt and separate into several clans. Some clans have their stations orbiting major asteroids (Psyche, Juno, Hygiea...) while Earth rule in others (Ceres and Vesta) and giant space mining companies own others (Pallas, Nemesis and small others).

Everything is going fine, building the narrative and writing well are more of a challenge (in Portuguese! To English is another long road) than building all the background, but one detail still bother me: years ago I read about quantum entanglement I thought was possible use to communication FTL. Shortly after that, I figured out that it really doesn't. I am looking for different options and the only one that seems possible is wormholes.

This bring one new set of challenges: how build a wormhole is main one. This Kurzgesagt video give some glimpses. I hear about Clarke's The Light of Other Days but still can't look for and not sure if worth in this purpose.

Building a gravitational well and establishing the wormhole with negative matter made in vacuum still seems ok in the scenario. However with some questions, lets say, engineering questions I would like some help:

1. What would be the size of wormhole to information only? This answer of Galactus Renan its a good start.

2.Once you have the one stable gravitation well opened with two mouths, how you would split it? Or in the other way, how you would take each mouth to their designated point?

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    $\begingroup$ Mm... Science based. That's a challenge. I'm thinking you are asking for a few PhD's worth of analysis to actually answer your questions. You might find some useful info on arxiv.org $\endgroup$
    – puppetsock
    Commented Mar 13, 2020 at 13:23
  • $\begingroup$ Maybe you could edit down your question to just the stuff that is relevant to your question? $\endgroup$
    – puppetsock
    Commented Mar 13, 2020 at 13:25
  • $\begingroup$ @puppetsock Describe some of achievements is an easy way to those ones will answer take a glimpse of technology level. I no found any satisfatory answer in other sources to it. Seems something need some sort of creativity to imagine. One worldbuilder's job. ;) $\endgroup$ Commented Mar 13, 2020 at 13:43
  • $\begingroup$ There are no asteroids in near earth orbit. Moreover, there are no known asteroids that orbit Earth at all. $\endgroup$
    – Anixx
    Commented Mar 13, 2020 at 17:05
  • $\begingroup$ @Anixx really?. Are you sure? $\endgroup$ Commented Mar 13, 2020 at 17:17

2 Answers 2


Galactus Renan here :D

  1. What would be the size of wormhole to information only?

If you only wish to pass information through, then any size you do - you could point lasers at it, and the light should come out on the other side. That way you could use light pulses to communicate in binary, computer language - or quantum computer language if you can do quantum things with the photons.

Aiming the lasers from the sender to the receiver should be really complex, but any society capable of creating wormholes in the first place would be far more advanced than us when it comes to computing and engineering anyway. I think it's doable.

I don't know how wormhole mass scales with size, but a wormhole with the mass of an asteroid or small planet could be placed around a star. It would orbit the star like anything else, and even if it is the size of, say, a basketball, you could still shoot lasers through it.

2.Once you have the one stable gravitation well opened with two mouths, how you would split it? Or in the other way, how you would take each mouth to their designated point?

If each mouth has gravity of its own, all you need to do is to pull it away - with gravity!

The sun orbits around the core of the Milky Way. As it goes, it drags the planets along. Just the same - a wormhole will orbit something. You just have to move that something.

Now sure, moving a star around may cause mayhem. Planets might escape or fall into the star as you move planetary and star masses around. But hey, you can't make an omelet without some interstellar destruction.

For ideas on how to move a star, here is more Kurzgesagt love: How to Move the Sun: Stellar Engines.

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    $\begingroup$ An one meter wide wormhole would have a Jupiter mass. So, suppose (just suppose before start to read it) that total of negative mass scales the width like square cube law. One nanometer wide wormhole (10^-9m) then needs only 1/10^27 Jupiter mass. Enough to pass light, and only 2 kg of negative mass. I m almost sure this calc is going wrong but need read the paper first. $\endgroup$ Commented Mar 13, 2020 at 16:40

I can't answer question number 2, but I believe the answer to question 1 is pretty easy.

The size of a wormhole that needs to carry information only is only a few inches or less.

The fiber optic cables that carry most of the entire internet are surprisingly thin (I work at an internet company, and those things get accidentally cut by backhoes at least once a year). The ones across the ocean are the only a few inches thick, and most of that is shielding. And that's with today's technology, one can only imagine the future.

Now, this is assuming that you either run a fiber cable through the wormhole, or perhaps it is a vacuum and straight so you can just use it as a fiber cable without much change. You'd probably still need to drop some signal boosters in there along the path though, even in the future.

Edit: There is some concern in the comment that even a few inches is a heavy enough wormhole to destroy the Earth. I say it's worth it to get streaming Netflix on Pluto, BUT, let's push the envelope a little. Let's say that over the next couple centuries we get really good at shooting a laser in a really straight line (low dispersion rate). Then we don't need signal boosters, or even the cable. The wormhole itself acts as a long range fiber cable.

In which case, it only needs to be about 650 nano meters wide (something like .000026 inches). The wavelength of red light. That way you send multiple signals down the line at the same time using different colors, and manage a pretty great level of data transfer.

So we maybe only destroy Florida? I'm not sure what the conversion rate here is, might be worth it.

  • $\begingroup$ The room to data need be enough to photons, the problem is all structure around: the negative matter most probably will block, the gravitational well need something to keep this gravity. Renan's answer linked says to an one-meter wide wormhole need something like Jupiter mass. $\endgroup$ Commented Mar 13, 2020 at 15:39
  • $\begingroup$ To harvest negative matter will need use space vacuum and to build everything seems impossible in surface. My initial plan is to something small enough to spaceships can carry, and be instaled in space stations but more than the masses, the total of energy and the fields seems a lot hard. A 650 nanometers wide in that previous calc will means 521.403 kg of negative matter. $\endgroup$ Commented Mar 13, 2020 at 18:26

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