5 ms·
A possible chink is that civilizations just don't do that -- carpet colonize the whole galaxy, or fill it with their probes to the extent that we seem them all
by shrimp_emoji 6y ago
A possible chink is that civilizations just don't do that -- carpet colonize the whole galaxy, or fill it with their probes to the extent that we seem them all over the place. The Fermi paradox relies on material (probes, colonies) and light (signals).
With the material explained away, the lack signals is much easier to explain in that we haven't listened long and we can only hear very loud signals. (Or maybe advanced civs don't use light and use gravity waves or tachyon beams or whatever, but you don't even need to go that far.) The only way we hear a signal is if it's:
1. loud (high energy) and aimed directly at us, like a tight beam
2. EXTREMELY LOUD and aimed everywhere, isotropically
1 is unlikely since they'd have to know where we are; 2 is unlikely since you're talking about an insane level of energy. If it's the case that civs don't seem to be making Dyson spheres or harvesting whole galaxies for energy, being able to throw around that kind of power is prohibitively expensive. In both these cases, the inverse square law applies (for every unit x of distance, the light's x² less bright). Ironically, that means we're more likely to detect signals from an improbably close civilization (like 4 light years next door, in Alpha Centuari), than from farther away -- and even then, by a chance sweep of an umodulated asteroid scanning beam[0] or something, if we happened to be paying attention at the time.
0: https://en.wikipedia.org/wiki/BLC1 https://en.wikipedia.org/wiki/BLC1
- jrumbut 6y agoDo you know if about any simulations of what it would look like if there were alien radio operators? If there were 50 other Earths scattered around the galaxy (ones that have been broadcasting like us but for longer) should the first television have imnediately picked up interstellar "I Love Lucy" or would it be faint anomalies from SETI? Somewhere in between?
- 7thaccount 6y agoThe milky way is 100,000 light years across and I love Lucy is what, 60-70 years old? I would say we've reached a very small portion of the milky way
- giantrobot 6y agoThe inverse square law says no [0]. Even relatively high powered transmitters aren't detectable for an Arecibo-class antenna more than a few AU from Earth. If you want a signal detected light years away you need it to be highly directional. An isotropic radiator emitting enough power to be detected light years away is called a star. So any SETI signals we might detect would almost certainly need to be intentional. That doesn't mean they would need to be responses to something we've broadcast just the sender was aiming their transmitter towards the solar system and sent a signal. [0] https://web.archive.org/web/20140719094337/http://www.computing.edu.au/~bvk/astronomy/HET608/essay/ https://web.archive.org/web/20140719094337/http://www.comput...
- gfxgirl 6y ago> A possible chink is that civilizations just don't do that -- carpet colonize the whole galaxy, or fill it with their probes to the extent that we seem them all over the place This assumes that there are gazillons of alien civs yet somehow they all come to the same decision. That's much less likely than gazillions of alien civs all make different decisions and it only takes a single one to make the replicating probs or try to colonize.