The year is 2015 A.D. the entire Earth stood still as humanity witness the arrival of an UFO.

A spherical object 10km in diameter is accompanied by 3 earth-sized planets, seemingly in orbit around it.¹

Not only have the alients not initiated communication nor responded to our hails, but it was completely undetected until it appeared suddenly 6 months out.

My question is how should humanity react to an uninvited guest from extraterrestrial origin? With so much at stakes and so little time left, should we be proactive or reactive? will Earth becomes its moon regardless of effort? (ETA 6 months, intention unclear, tech unspecified, propulsion speculative, confirmed it's alien)

Note 1: it's important to the story that the 10km probe "own" the 3 Earth-sized objects, as this opens up the idea that it might take our Earth, too! So another issue is how would we tell this is the case and that the tiny probe even exists, rather than just seeing a triangle of 3 masses orbiting a mutual center of gravity?

  • $\begingroup$ If this probe is directly causing the objects to orbit, then its technology is so far beyond us there's nothing we can do. If this probe is causing the orbits by gravity, then it's actually a magnetar and we're screwed before it even comes near the Solar System. $\endgroup$ – Frostfyre Jul 25 '15 at 4:14
  • $\begingroup$ @Frostfyre a magnetar don't sneak up on us and is there any way to kill time like put up resistance to dissuade the alien? $\endgroup$ – user6760 Jul 25 '15 at 4:36
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    $\begingroup$ I saw a documentary on this once. Don't send out helicopters with strange light shows. It doesn't work. $\endgroup$ – corsiKa Jul 25 '15 at 6:26
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    $\begingroup$ Voting to close: idea generation, and the question seems to lack basic research regarding sense of scale and space detection technologies. $\endgroup$ – o.m. Jul 25 '15 at 7:01
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    $\begingroup$ "probe with an estimated diameter of 10km draws near" size given. I don't see anything in your comments elaborating on that. We somehow just know that, and then spot 3 spheres 4000mi in radius using a telescope that must have been told where to aim before it saw that, and impliy that we didn't know about that via other instruments already. Eluding radar is not the most perplexing, or even a serious question. $\endgroup$ – JDługosz Jul 25 '15 at 9:28

What can the central object be?

  1. Black hole surround by an constructed shell.
  2. Artificially constructed neutron star -- 20 km diameter is smallest naturally occurring neutron star.
  3. Artificial construct generating an intense gravitational field or equivalent to bind the 3 planets.
  4. Something else even more incomprehensible to us.

Only case 1 sounds like something we could even plan on doing, assuming we just happened to find a primordial black hole. Once again, the central diameter is too small for a black hole from a star. The naked singularity is smaller, but it is below the event horizon and nothing could be constructed and visible existing inside the horizon. So you need a primordial black hole smaller than 10km. To keep the 3 planets in orbit, it still need to fairly massive. Just getting close to the earth will cause lots of problems for us.

The technology to build the shell able to withstand the tidal forces is yet again magic level. Also any inhabitants would be ripped up by tidal forces unless they are artificial or protected by gravity control or suchlike.

I don't carry on a conversation with ants. I ignore them or destroy them as I please. The ants have no say in the matter. Now, an entomologist might be interested in studying the ants, someone else might want an ant farm. But in no case do the ants have any influence in the outcome. Should the ants bite or get into my food, I am more likely to destroy them than otherwise.

Just getting here from another star star implies technology well beyond our current level. Doing so in style bringing along 3 planets and something beyond our understanding at the core ups the game by a huge amount. The aliens are far, far beyond our technology.

If the aliens are for some reason friendly, they will study us, contact us, etc. as they see fit. If they are hostile, we are completely toast. If they are indifferent, it would be best not to annoy them.

The winning strategy is to lay low and respond politely if they initiate contact. Maybe we should try to be on our best behavior, knock off the local wars, etc. to look like a cute puppy instead of a mad dog that should just be put out of its misery.


The comments thread is getting a bit unwieldly for answers with links so I'm putting this into the answer format, even if it is really a comment. I questioned the question as (a) too broad when it comes to human reaction and (b) not consistent with 2015 detection technology.

Say an object with 10 km diameter comes from deep space into the solar system, orbited by three planet-sized objects (call them 10,000 km diameter).

  • Detecting the triple planet should be about as difficult as detecting Pluto and Charon from Earth. Pluto was initially discovered by looking at disturbances of other planets. Current surveys use telescopes. No radar involved, so the lack of a radar signature of the probe is not detected.
  • Once the unusual triple planet is detected (Pluto has just two big ones) people on Earth might direct their attention there. Here is a picture of Pluto from Earth. This is what Hubble tells us about Pluto.
  • The three bodies would be expected to orbit around their common center of gravity. Some scientists might ask why they didn't crash into each other long ago, but the average guy on the street wouldn't understand the question.
  • Pluto has plenty of moons, so a short glimpse of the alien probe should be dismissed as something like that.

So we wouldn't expect detailed data from those strange worlds until we get a probe into the area. The probe would carry a limited set of sensors and rush by with in a single high-speed pass, all predetermined when the mission was designed.

At best we'd get ambiguous readings from the scientific sensors, and we'd debate for decades if they warrant the expense of a new mission to look closer. Perhaps there will be a History Channel episode. Sceptics would call for another planetary science mission, instead of wasting money on a weird alien hunt.

Summary: Earth doesn't stand still, because Earth doesn't really notice anything weird with 2015 tech.

  • $\begingroup$ Maybe the new horizons probe just happened to be in the area and noticed the alien probe, so they pointed the Hubble to try and investigate the unexpected change in trajectory. Yeah, you're right the question was pretty far fetched this way too. $\endgroup$ – Gary Walker Jul 25 '15 at 10:27

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