https://en.wikipedia.org/wiki/KIC_8462852 summarizes situation. I think there now is a decent chance (>10%) the explanation for this is, there are mega awesome space aliens hanging out near the star KIC 8462852. Basically because nobody can think of any alternative explanations that seem plausible. At least I can't. If this really is little green men, they're using something like 20% of the entire power produced by their star. Which means, wow. In comparison, the Earth intercepts 5*10^(-10) of the sun's power. So, herein, let's do some elementary calculations related to: Do those aliens know about us? And what might they do about it? One can also ask, if so, then what *are* they going to do about it? Sure hope they don't dislike us. If they for some reason wanted to destroy humanity, they might be able to. So, first of all, if they were going to spot us by telescope, then one could imagine at best (?) they have a telescope with aperture the size of the solar system (radius 5*10^15 meter), looking at us in UV light (wavelength=200 nm=2*10^(-7) meter), and, e.g, to detect life on earth they detect the ozone layer indicating free oxygen. At worst one might imagine they have a telescope only 1000 meters in diameter checking us out. Assume diffraction limited optics. They are 1400 lightyears = 2.3*10^19 meters away. Earth-sun distance is 1.5*10^11 meter. Earth diameter is 1.3*10^7 meter. To see earth as distinct from sun, they need [ 5*10^15 * 1.5*10^11 ] / [ 2*10^(-7) * 2.3*10^19] big. To see features on Earth itself, they need [ 5*10^15 * 1.3*10^7 ] / [ 2*10^(-7) * 2.3*10^19] big. To directly see, say, a city like ancient Rome, now using 500 nm light, they'd need [ 5*10^15 * 10^3 ] / [ 5*10^(-7) * 2.3*10^19] big. Those are best case for the aliens using telescopes. Worst case, they'd need: [ 10^3 * 1.5*10^11 ] / [ 2*10^(-7) * 2.3*10^19] big and [ 10^3 * 1.3*10^7 ] / [ 2*10^(-7) * 2.3*10^19] big. for the first two tasks. So clearly the aliens should already know Earth exists. They might not yet have noticed it contains life -- that depends how hard they tried to find out. If they tried hard to look at us, then they'd know. If they then tried even harder to look at us, they might even be able to already know Earth has intelligent life. They also could have sent out probes which would somehow have reported that information back to them -- depending how old they are. Now in about 1300 years the aliens will first be able to receive radio transmissions from Earth. Furthermore, we could starting soon make an intentional effort to beam signals at them, in which case they might receive them in 1400 years. Suppose we beamed 100 megawatts of signal power at them using earthwide network of linked radio telescopes (effective aperture 2*10^6 meter) using 1mm wavelength and kept doing it for years. That seems about the most noticeable thing we could do within the next 10-20 years. If so, then I believe we would be able to make ourselves both (a) distinguishable from the sun, and (b) detectable even by current earth based radio telescopes (if aimed at us from there). The detection problem then would be comparable to us receiving signals from current spaceprobes in the outer solar system. I do not know if that'd be enough to make them notice us, but it'd have a decent chance of working. We could then send them whatever at bitrates comparable to outer solar system spaceprobes sending us data. And they, 1400 years later, could send us return mail, if so reaching us an additional 1400 years later. It helped in these estimates to be able to assume those aliens are tremendously advanced. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)