(Disclaimer: I tried this question earlier in the scifi site as well as real science sites, and was told should be on topic here)

I'm writing a speculative story about aliens coming to earth - and just wanted to bounce a couple of ideas for scientific accuracy (or at least lack of obvious impossibility).This is set in the near future (~2050s)- and it's more of a comic story so the details need not be exact. If the alien ship jumps into the solar system (i.e. after super light flight) about ~2 Million Kilometers from earth - what would pick it up first? I guess at certain point of time all big observatories will - how long might that take? Also - another point is communication between the aliens being picked up by one guy (however not by the governments). It's something like this - there is a network of satellites used for providing internet connection - and the communication between the alien crafts caused interference with this in some areas (maybe due to the same frequencies? Ka band?) which our guy was able to pick up, isolate and decode...however no official space agency did. Is that possible?

I don't have much background in radio communication - so apologies if these questions sound very amateurish... Appreciate any and all help!

Cheers. Wizkid

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    $\begingroup$ Why don't you try to seperate your questions out se we can read them, and make sure that every question you have is marked by a question mark, I think "Also - another point is communication between the aliens being picked up by one guy (however not by the governments)." should have a question mark, right? Anyone, this also might need to be two questions it's hard for me to tell. $\endgroup$
    – DonyorM
    Oct 16, 2014 at 5:08
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    $\begingroup$ My first question would be why are the aliens using radio frequencies to communicate at all? especially if there is only one ship? $\endgroup$
    – bowlturner
    Oct 16, 2014 at 11:16
  • $\begingroup$ Why was this question posted a second time? $\endgroup$
    – HDE 226868
    Oct 25, 2014 at 19:45
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    $\begingroup$ @HDE226868 Because the question you link to was migrated from Amateur Radio, where this was also posted. $\endgroup$
    – user
    Oct 29, 2014 at 9:51

4 Answers 4


I remember seeing this question on the Astronomy forum. Yup, this seems like a better location for it, though the skills required to answer do tend to cross over. Hopefully you'll get what you are looking for. Here's my attempt:

2 million kilometers is really not far in astronomical terms, the earth moves about 2.5 million km a day, so if they appeared directly in front of us, we'd crash into them shortly. ;) But depending upon the size of the ship, and how many of them there were, it still might be very difficult to detect. Check out NASA's Near Earth Asteroid Tracking program for solid information on the size, position and count of objects we are currently tracking. But for something, say, the size of a medium-sized city, I'd put it much further out to be safe. Perhaps 50 million km or more.

If literally one guy discovers this before anyone else, then this guy is looking at something no one else is. The scenario you brought up seems unlikely since there would probably be a million people or more using that.

Not to write this for you, but I would recommend something like a graduate student writing a program to predict weather patterns on Saturn by studying electrical interference in the radio spectrum. He would probably initially throw out his data because an intelligent pattern would mean interference (See third paragraph here on Penzias and Wilson's discovery of the Cosmic Microwave Background) Eventually he would look into the source of the interfering signal (but it would likely take days), and back to your regularly scheduled program.

There are thousands of grad students working on very specific areas of the sky in very specific bands for very specific purposes, and they are the only ones (or in many cases part of a small team) who are performing that one task in all the world, so your premise is plausible.

  • $\begingroup$ One possible wrinkle... If it has any kind of power systems, such as engines or life support, the ship will almost certainly be emitting some kind of thermal signature in the infrared range, which would probably be quite apparent to anyone looking (more so than asteroids). I don't know who would be likely to be looking. This is independant of visual or radio detections. $\endgroup$ Oct 16, 2014 at 7:32
  • $\begingroup$ @CalebHines only if people are looking in the infrared rather than just the visible $\endgroup$ Oct 16, 2014 at 9:13
  • $\begingroup$ @ratchetfreak But we do: cnn.com/2009/TECH/space/12/14/wise.spacecraft.launch (News article: "NASA launches infrared telescope to scan entire sky") $\endgroup$ Oct 16, 2014 at 13:12
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    $\begingroup$ For an example of just how easy this heat signature might be to pick up on, see this answer: worldbuilding.stackexchange.com/questions/672/… $\endgroup$ Oct 16, 2014 at 13:12
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    $\begingroup$ @MBurke That's exactly what astronomers do every single day, for at least the last 100 years -- Pluto was discovered in 1930 by using this technique. en.wikipedia.org/wiki/Blink_comparator Modern software does the work that the old "blink comparator" did, but it's the same principle and would indeed, as you suggest, make finding the sudden appearance of a hot object very simple. Assuming, of course, someone happens to look in the right direction in the first place... $\endgroup$
    – Kromey
    Oct 16, 2014 at 16:34

I know that this question is pretty much off-topic and might be better asked in the sci-fi stackexchange, but I can't resist answering because it's a little nerdy.

  1. It is impractical to provide worldwide internet using satellites, unless latency really is not an issue (and it generally is). This is pretty much due to the fact that in order to be most useful the satellites would want to be geostationary, and the Clarke Belt is about 35,000km away from the Earth. Because of the speed of light, this means a 0.2 second round-trip time for signals from earth-to-satellite-to-earth - and much longer if it's earth-to-satellite1-to-satellite2-to-earth.
  2. Moving to the realms of fiction for a moment, it would be quite likely that any culture that developed superluminal travel, would also be highly likely to have developed superluminal communications technology (similar to the oft-used 'sub-space' communications often used in sci-fi stories). Since this is not actually real (as far as we know! Yet!!), you could ascribe to this technology any properties, such as having it interfere with our technology when it is used. But conversely, it would be difficult for us to detect directly since we don't possess that technology itself. We could probably only detect its use because of the side-effects it has on our own technology. You could use this as a plot device, and it could explain pretty much everything you describe in the question. Since it's fiction (and science fiction, at that!), all you have to do is invent some technologies, and work out ways for it to fit the story.
  3. Because of the vastness of the skies, it is wholly possible that one man or woman could find something before an organisation or government. Radio amateurs do tend to have highly-directional antennas pointed in the general direction of the sky, and it could be that one guy (or gal)'s equipment suffered problems whenever his/her antenna was pointed at one exact spot in the sky - and he could take that information to his/her local radio club, where other people later experiment and try and find the same thing.

It would probably be worth visiting a radio club to get a feeling for the general atmosphere at such places, and to see the kind of things that people discuss.

I know the question is generally off-topic for this forum, but apologies again for being unable to resist answering it :)


Let's assume that super light speed is possible (against the claims of main stream science).

Assuming this, let's ask about the consequential scientific/reality-check issues.

One has to ask how much energy would be needed to stop an object travelling at the speed of light or higher speeds. If the stopping distance is anything less then a few million light years, then the amount of energy discharged would be so enormous that it would surely blast our entire solar system into deep space at ultra high velocity. But all of this depends on the same $ E = m \cdot c^2 $ that prevents super light speed and since we are ignoring this we will ignore its consequences here too.

Let's say the vessel has used some sort of wormhole to achieve a gentle jaunt across a vast distance in a short period of time while the crew review their devious plans. Opening up a wormhole in our local neighbourhood would certainly produce an earth-shattering amount of energy, but let's ignore this too and say that the amount of energy generated is not earth-shattering. At a distance of 2 million kilometers the most likely first detection would follow when satellites stop functioning as they are irradiated by resulting energy or thrown out of orbit - this is assuming the absence of an intense flash of energy in the optical spectrum that was detectable across earth by the naked eye.

Well, you did ask for a reality check. So let's ignore all of this and arrive at the scenario of minor locallized disruption to internet communictions following an undetected arrival. While it is possible that our guy could be the first and only to detect an anomalous signal, it is difficult to understand why he would recognize its significance rather than writing it off as something he did not understand. Further, assuming that he has the know how to isolate the signal, for me personally, it simply defies credulity that he could decode and understand such a signal. Indeed, any alien race with such advanced, god-like technology would surely employ unbreakable encryption in their communications and be able to move amongst us undetected.

So that's my reality check. On the plus side, none of these issues need be a problem if the story is good.


What would be the first thing to notice? Assuming the correct hemisphere and on the dark side, the LSST will add a time dimension to astronomy, tracking tens of billions of visible objects every few days. It will be a public database, with alerts noting things of interest. A that's new! notice might be followed publicly by a great many people, both with telescopes and just watching the web and chatting.

This would be a great thing to detail in a first-contact story. It could be seen within the week (next pass) of appearing, or it could appear on the day side and not get tracked for a few months (if it's in the outer system and doesn't move with the Earth as it moves to the other side of the sun) and make a ruckus with everyone speculating where it came from without necessitating a sudden FTL appearance.

With the new bright spots on the eastmost strip, they will generally be comets and results of asteroid collisions that change what's charted, and largely automatically processed. There might be some conspiracy-theory sub-plot concerning the disposition of one particular new bright spot near Saturn's orbit. Then it's found to be in circular solar orbit, not an incoming comet...


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