This answer explores what we can learn from alien starships in orbit around Earth. But what if the aliens went a step further: They send a shuttle down. Humanity dispatched interceptor aircraft, but they were shot down easily. The shuttle landed in a major city, and alien ground troops started to search buildings, killing everyone who was stupid enough to resist. Then, they took off again. They did not take anything or anyone.

My questions are:

  1. What can we learn about the aliens from this encounter?
  2. How can we prepare for a second attack?
  • 2
    $\begingroup$ This is the epitome of story-based questions. Tell us your story and we'll tell you what can be learned from it. You explain nothing. Nothing about your aliens, their technology, their behavior or reasoning. Nothing about what the humans can or do observe or capture. You tell us nothing, and ask us to explain what humans could learn and how they could prepare for another attack. What worldbuilding rule are you asking about, because it looks like you're not asking about one or even trying to build a world. VTC. $\endgroup$ Nov 28 '20 at 5:16
  • $\begingroup$ I wonder what the rationale is for reopening: the OP hasn't addressed JBH's astute criticism, and he's still asking too many questions. (Of course, you can't prepare until you learn, but those are two quite different questions.) $\endgroup$
    – elemtilas
    Nov 29 '20 at 3:37

Hopefully, answers to questions:

This is pretty open-ended, so it needs to be pretty generic.

How do they move? What equipment did they use, and what did it do? Do they breathe our air? Do they prepare for violent opposition? What dangers did they avoid or ignore? If they can't be harmed, why repel attacks? Do they leave chemical or biological residue? How did their weapons kill? Did they communicate visually? Defend against poisons/biologicals? While searching, what did they spend time looking at/in? How did they function as a team or individuals (did behavior towards one influence others)? Did they attack armed people, or only those seeking to harm them?What about those who were merely in the way? Did they respond to attempts to communicate? Did they respond differently to animals? Can we deduce the power/output of their shuttle and devices? Were they looking, or scanning for things?

  • $\begingroup$ Nice to see someone thinking through the questions that can reasonably be asked about the alien attack. Well done! $\endgroup$
    – a4android
    Nov 28 '20 at 6:15

The question describes a raid, not an attack

Raids have specific purposes. We can eliminate some of those purposes based upon the description.

  • demoralize, confuse or exhaust the enemy
  • ransack, pillage or plunder
  • destroy specific goods or installations of military or economic value
  • free POWs
  • capture enemy soldiers for interrogation
  • to kill or capture specific key persons
  • to gather intelligence.

We can make a pretty good guess about the alien objectives of the raid. We lack enough data for real insight on their goals or strategies they plan to use to achieve those goals. But we do learn some things:

  1. Some of the capabilities, speed, size, and (in)vulnerabilities of their ground troops.

  2. Some of the capabilities of their air power, and a space-to-ground and ground-to-space flight profile.

  3. Warning time available for future raids/attacks, and threatened area based upon first detection.

Getting into somewhat more fanciful guesswork:

  1. If the purpose of the raid was to make a (political) statement ["you are defenseless against us"], then it's quite possible that the aliens want us alive, not exterminated.

    Since we have something they apparently want, this suggests the possibility of negotiations.

  2. Since the aliens did not kill seemingly unresisting humans, this suggest several possible tactical alternatives to protect the population. The great thinkers should start looking for ways to resist without seeming to.

    Since the Western strategies of war generally try to avoid cities (they are big force-eating traps), the generals must reverse their thinking -- cities full of "non"-resisting civilians may be the best way to conserve combat power and skilled fighters while the Earth builds it's force capable of throwing off the yoke of the aliens.

  3. If the purpose of the raid was to acquire or confirm information, then it implies that the aliens are not (practically) clairvoyant or all-observing. They may be vulnerable to deception.


probably just to give a message or a warning or display their power in general

it can also be use in Gunboat Diplomacy

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generally to counter it is to build better weapons and increase the defense, and conscript and drill the resident into militia since the alien can land into big city which has lots of civilian, and since they dont take any valuable without any warning or contact can be mean they may think human is worthless or inferior technologically and physically, which probably not far away for them to eradicate human if they want to.

oh yeah one thing for sure, this alien aggressive action clearly mean war or want to pick a fight.

  1. They are bad of ass.

  2. It was not an attack, because we would be mush. They had a mission and we got in the way.

  3. We can prepare for a second "attack" by busting out our best manners, listening and watching more and shooting less.

  4. Events show that we are mind-numbingly stupid, and so we would do well to review the events that happened. The fact that nothing was taken does not mean that these aliens did not accomplish what they wanted to do. We would do very well to reconstruct exactly what the aliens did do without jumping to conclusions about their goals or purpose.


I think I'll go with the (nearly) opposite of Willk's answer.

  1. They are (somewhat) bad of ass.
  2. Unfortunately for them, we are more bad of ass. After all, Kinetic Weapons Are Just Better.
  3. Unfortunately for us, we are only slightly more bad of ass. As a result, we can prepare for a second attack by busting out our best troops, listening and watching more, and shooting first.
  4. Events show that we are mind-numbingly stupid when it comes to dealing with alien invasions. As a result, we would do well to review the events that happened. That way, we can do a better job of exterminating them before they exterminate us.

Simple, lure in a squad of said aliens into a predesignated location, they get there, and a full-on army confronts them, and prevents their escape. Then we capture the aliens using stun technology and study their behavior, weaponry, equipment, physiology, etc. Then armed with the knowledge of all their weaknesses and such, we take them out.

Not to mention, replicate their armor and weaponry to use against them

Basically, Xcom them

  • 1
    $\begingroup$ This only works if the aliens are at a comparable technological level as humanity. If the aliens have the firepower to vaporize a full-on army in a second, are immune to stun weapons, and their armour & weaponry requires technology millennia ahead of us our ability to replicate them will be zero, then it might not work. $\endgroup$
    – a4android
    Nov 28 '20 at 6:28

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