The setting: an alien crew has a shuttle landed on Earth in the 1980's. Their main ship is extremely damaged and beyond reach somewhere in the Milky Way. Their shuttle cannot escape Earth's atmosphere. They are in an unpopulated forested area to avoid encountering the locals, which would be both a galactic crime and unsafe. Earth's gravity is uncomfortable but livable. They leave their shuttle only in EVA suits after decontamination.

The crew has begun transmitting a distress signal, hoping it reaches a stealth satellite belonging to the galactic republic that Humanity doesn't know about. Humanity is seen as a primitive pre-FTL race and as such their solar system is analogous to a nature preserve. Nobody will come save the stranded aliens if they don't make contact. This galactic republic has done some research and common Human languages are in the catalog for the crew's universal translators.

Reptilians secretly in control of Earth's governments have intercepted the distress signal emitted by the shuttle, jammed it with satellites, and sent their men-in-black agents to capture (or eliminate) the marooned alien crew.

There is a human from the distant future of a parallel universe who notices the agents moving in on the shuttle. He has access to extremely advanced technology, has drones and a heavy mech suit designed for research and exploration of any environment. He is not aware of the galactic republic and knows nothing about the stranded aliens other than what his drones have revealed with their reconnaissance. He wants to warn them about the agents who are approaching them. How does he do this?

EDIT: some clarifications were requested. In the future man's parallel universe, there was no galactic republic, and in fact there were no aliens at all as far as they knew. All of his equipment was designed for the scientific study of parallel universes after it was discovered how to traverse them. The primary purpose of his drones are for scientific observation, to gather data from a multitude of angles, so they aren't really equipped to interface with alien machinery. The man also has a full-body EVA outfit worn within the outer mech suit that features a form of optic camouflage, allowing him to study things up close. The man cannot return to his home world at this time.

Since the alien shuttle began transmitting shortly after landing, I would give it only a matter of days before the Reptilians closed in on their location. Once their agents are in the forest, hours. Neither the aliens nor the future man are aware that the distress signal is being jammed. The future man's suit wouldn't have enough Delta V to escape Earth's orbit and disable all the jamming satellites anyway.


closed as off-topic by sphennings, L.Dutch, Vylix, Slarty, Mołot Nov 26 '17 at 10:47

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  • $\begingroup$ You're asking how people should ask in a scenario. Such questions aren't about building a world and as such are off topic for this site. $\endgroup$ – sphennings Nov 25 '17 at 14:22
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    $\begingroup$ @sphennings The question is about how to communicate with aliens who happen to be in danger. The OP has given the context for why he wants and needs a strategy for alien communication given the situational constraints and parameters of his scenario. Alien communication is an element of worldbuilding. $\endgroup$ – a4android Nov 26 '17 at 3:30
  • $\begingroup$ @a4android "How do aliens communicate?" would be on topic but pretty POB. "How would you alert an alien crew that they are in danger?" is asking how a person could solve a problem given the constraints of a world. The question is asking about the actions of an individual. Such questions are explicitly off topic for this site. $\endgroup$ – sphennings Nov 26 '17 at 3:45
  • $\begingroup$ I enjoyed the scenario, but it was legitimately over-complicated. There are like four layers of sci-fi scenarios engaged here (Galactic Republic, reptilians in charge of Earth, person from future, person from parallel universe). I would prefer a simplified setup and a better description of expected technology levels. $\endgroup$ – kingledion Nov 26 '17 at 5:48
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    $\begingroup$ @sphennings That constitutes a strategy to do something which is a worldbuilding element that is welcomed here. $\endgroup$ – a4android Nov 26 '17 at 5:57

Attack them.

Should get the message across. Don't hurt them of course, just a warning shot.

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    $\begingroup$ That's... actually not a terrible idea. Maybe if they refused to listen he could force their hand... some of the aliens would definitely not trust him after that, but I could see some of them realizing it was a warning shot to alert them to the real danger. Interesting twist... $\endgroup$ – Dakacha Nov 25 '17 at 12:07
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    $\begingroup$ They never have to know who did it, just a bullet hitting the hull near one of them, they'll be careful afterwards. $\endgroup$ – DonQuiKong Nov 25 '17 at 12:13

He supposes that this race is highly advanced and just speaks to them using natural language. And since "galactic republic has done some research and common Human languages are in the catalog for the crew's universal translators", they understand him.

  • $\begingroup$ Devil's advocate: he doesn't know that they would understand him, and it would probably take the translator a few sentences to recognize the language. There is also the decent possibility that some of the crew would attack him on sight. $\endgroup$ – Dakacha Nov 25 '17 at 6:25
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    $\begingroup$ Well, he has drones to deliver the warning. He already uses them to watch the crew, and knows they are sentient, so it's worth the effort. In the worst case, drone itself will be such warning. $\endgroup$ – ZuOverture Nov 25 '17 at 6:29
  • $\begingroup$ I like the train of thought, but devil's advocate again: the drones are primarily for scientific observation. In fact, the future man's entire suit was designed for scientific study of parallel universes after they developed the technology to traverse them. The drones have a degree of autonomous AI, but do you think they would have some form of audiovisual output without first interfacing with some kind of speaker/display? I'm not saying it's out of the question, just wondering what form of communication they would have under those circumstances. $\endgroup$ – Dakacha Nov 25 '17 at 7:38
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    $\begingroup$ Those advocates ) Anyways, drones have scientific equipment which can be used in an alternative way, not necessarily envisioned by it's designers. With spectroscopy lasers, for example, they can engrave messages on different surfaces. With relatively fast kinetic actuators (manipulators) or other oscillating volumes (plasma arcs and combustion engines come to mind) they can create modulated acoustic waves, i.e. reproduce sounds. Drone can write on sand or clay with his own movement traces. Swarm drones can build a visual image with themselves. Possibilities are endless. $\endgroup$ – ZuOverture Nov 25 '17 at 8:24
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    $\begingroup$ Given that he's from a parallel universe, does he speak any of the languages of the planet in this universe? $\endgroup$ – celtschk Nov 25 '17 at 14:39

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