In a Mass Effect series, Reapers are an army of living machines that harvests all advanced intelligent civilizations in cycles of tens of thousand years. The Prothean race, which are the most advanced civilization in the galaxy, wants to trick Reapers that some potential races are less advanced than they really are in order to give them head start for the next cycle.

If Protheans want to make humans look primitive, what would be the most humane way to do it, with least amount of killing?

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    $\begingroup$ Hello, and welcome to this site! Could we have some precisions on what your races consider to be "primitive" and how they mesure it? If they are superpowered aliens, maybe we already look primitive to them... $\endgroup$
    – PatJ
    Jan 25 '17 at 0:09
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    $\begingroup$ It really depends a lot on how much time and focus the Reapers are willing to spend trying to uncover advanced civilizations, and how advanced they themselves are, meaning, e. g. how sensitive their sensors (or whatever) are, whether they take samples (individuals, machines, information) from the other civilization to check for signs of hidden technology, etc. Knowing there's such a thing as Reapers around would be a huge plus for any civilization, in any case. $\endgroup$
    – pablodf76
    Jan 25 '17 at 1:04
  • $\begingroup$ I'm voting "unclear what is being asked" unless we get a better definition of "sufficiently advanced." $\endgroup$
    – SRM
    Jan 25 '17 at 1:31
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    $\begingroup$ Define primitive. $\endgroup$
    – jamesqf
    Jan 25 '17 at 4:23
  • $\begingroup$ @SRM The OP doesn't use the phrase "sufficiently advanced". Why ask for it to be defined? Oh yes! The question seems clear enough to me. A simple deception really, it may be difficult to implement though. $\endgroup$
    – a4android
    Jan 25 '17 at 5:54

By taking Mass Effect as a reference you can also have the technological level that triggers the annihilation.

In the game, as the Reapers destroy humans and other sentient species, they also avoid the Yahg and let them survive for the next cycle. The Yahg technological level is described as:

When Parnack was discovered by Citadel Council surveyors in 2125 CE, the yahg were a pre-spaceflight civilization with technology equivalent to that of 20th century Earth.

So two elements seem important here:

  • pre-space flight
  • 20th human century-like

Long range: As @Twelfth and @JDługosz explained you need to protect yourself against long range detection. However 20th human century-like doesn't imply no emission at all but a lower energy level and bad quality and speed.

In addition to other answers about reducing the EM radiation I suggest to send fake signals. Indeed, as the Reapers might decode the video and audio signals from earth, you can send very bad quality images and audio picturing a way less developed world.

You should also stop all probes sent in outer space from emitting and if possible destroy them.

Fly-by: If the Reapers decide to check by them-self and to go closer to Earth the situation becomes a bit more complicated. You need to get rid of all spaceflight technology proofs, including satellite, scraps, moon landers, rovers and probes on other planets ... (And definitely get rid of the EM shield if you built it)

As they can take pictures of the ground you need to cover and disguise all technological advanced buildings and sites. Using the same kind of trick of Ghost armies could be very useful (without forgetting taking in account the scanning technology level of the Reapers).

Agents: If the Reapers send agents on the ground to check ... I can't see other solution than actually downgrading your technology. Difficult to figure out how to remove everything on Earth related to modern technology, including waste (if we could we would already have solved a big part of our ecological problems).

If you can achieve that, time capsule with blueprints and instructions to rebuild our technology could be handy once the Reaper have left.

  • $\begingroup$ Bzzt. Long-range detection is irrelevant. There are species that the Reapers know about but let live (at least, the question says so and docs elsewhere imply that ... I don't know the game world directly). So who knows what constitutes a threat to the Reapers? Only the OP can answer. $\endgroup$
    – SRM
    Jan 25 '17 at 6:41
  • $\begingroup$ @SRM I would guess it's not so much long range detection of your civilisation, but rather long range detection of your civilisation as sufficently advanced as to have to be destroyed. A society that seems to be at mid 20th century technology would be ignored by the Reapers. $\endgroup$
    – Sarriesfan
    Jan 25 '17 at 12:12
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    $\begingroup$ Continuously telecast political debates and opinion shows from pundits on every possible band. When the aliens decode it to work out the technology level, they'll write us off as obvious morons. $\endgroup$
    – nzaman
    Jan 25 '17 at 13:18
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    $\begingroup$ @Sarriesfan Would it? David Weber's book "Off Armageddon Reef" has aliens who extinguish other species capable of creating a right angle piece of metal. That's a lot further back than just 20th century. $\endgroup$
    – SRM
    Jan 25 '17 at 15:31
  • $\begingroup$ Why do you need that much broadcast EM in a technically advanced society? Broadcast is inefficient: as I believe someone said, if your TV broadcasts are reaching the stars, you're losing money. Internet can be (and largely is) run on optical fiber. If you really need cell, build your towers with directional antenna that don't beam energy upwards. And so on. $\endgroup$
    – jamesqf
    Jan 25 '17 at 18:47

I'm familiar with the Mass effect series to some degree, but there isn't much for specifics on what constitutes an advanced civilization...there is actually a good chance 21st century earth is still primitive at best.

Since Mass Effect relies heavily on element-0 (good ol eezo), I would suggest that the detection of element 0 and the usage of it would constitute detecting an advanced race (simply put, you don't use eezo you are not suficiently advanced). Shielding or hiding all traces of a civilizations would simply be hiding the use of element 0.

Since we're talking todays world and not fictitious eezo, I would suggest the most likely method the Reapers would use to detect advanced civilization would be to detect the EM radiation coming from each planet. We create quite a bit of this today and send EM radiation in all directions from our planet. Masking these EM signals becomes the simplest way of keeping us looking primitive...a electric field encasing Earth that either blocks outgoing EM radiation, or at very least scrambles it so badly that it looks like background radiation would be your most likely route.

If you don't like this answer, you'll need to define " all advanced intelligent civilizations" and " look primitive" much further.


How primitive do you need to go? If you need to go back to a pre-spaceflight society, you'd need to eliminate all spaceflight. Which would for most people on the planet mean no more GPS navigation or foreign television and that's about it.

If you need to go back to a pre-electrical society, you'd need to start killing most of the urban and suburban population as without electricity there'd be no way for cities the size we have now. This gets worse if you need to go so far as to eliminate internal combustion engines. If you have time, this could possibly be achieved by a temporary ban put in place on having children. By enforcing this only on urbanites and strictly enforcing a ban on more than 2 children on farmers, urban populations would dwindle.

Go back to a pre-metal society and you'd have to effectively reduce the number of people to a stone age society level of a few tens of millions of people worldwide at most (down from a current level of between 7 and 8 billion).

Pretty much the only way to achieve that is through "active measures", probably a virulent biological or chemical weapon that rapidly kills the entire population, except a few choice individuals who happen to be immune. And you'd be no different from the others whp're intent to kill all technological civilisations...

So everything depends on how primitive you need to go.


Long-range detection: reduce E-M emissions and spectroscopic evidence of industrialization.

A super advanced technology could appear as no technology: people live in seemingly primitive dwellings among nature, but all their needs are met with biotech and nanotech, without having to work hard or rely on natural weather etc.

A planet might develop advanced biotechnology and not have steel. Their industrial revolution is based on designer species of animals and microorganiems. That leads to nanotechnology a couple hundred years later, while never looking like what the invadors presume advanced technology should entail.


Do the Protheans have the technology to Mask, block or deflect EM Radiation? ie Radio signals? Kind of like and scrambling/in-cription of radio data like the Military sincgars radio system.

Why would the Protheans not just create a radio signal camouflage field. Why: 1. No casualties, 2. No contact needed with the Terrans, And 3. in nature the best camo system means the best chance of survival for those of us species who are a bit lower on the food chain. Cover and Conceal of our civilization.

To date Humanity as sent only one object out of our home system, Right. I think we might be really easy to hide now.



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