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Hmm... If there was an earth 2, with the exact same properties, and a population of human lookalikes at the exact same level of tech as us, how far away would t
by klmadfejno 6y ago
Hmm... If there was an earth 2, with the exact same properties, and a population of human lookalikes at the exact same level of tech as us, how far away would they need to be for us to have not detected them by now assuming we rolled a 10 for our perception check?
- jjk166 6y agoThe Very Large Array (VLA) could pick up a broadcast from a geostationary communications satellite at a distance of 0.14 lightyears. The planned Square Kilometer Array (SKA) would be able to pick up the same signal within 500 lightyears. A radio telescope with detectors on opposite sides of the earth could pick such signals up from 2000 light years away. The nearest 2000 lightyears make up 0.16% of the milky way galaxy.
- klmadfejno 6y agoHmm that's an interesting way to think of it. At 0.16%, assuming uniform distribution of detectable aliens and none detected in that range, that would estimate an upper bound of 625 alien species in the milky way. That does feel kind of lonely.
- jjk166 6y agoThat would be 625 species with radio technology at approximately the same level as ours. Presumably as technology progresses, their transmitters and receivers improve whereas the distance over which they communicate stays relatively constant and thus their output power should decrease. It's also possible a more advanced civilization uses other communication methods, for example optical fiber might render satellite communications totally obsolete. Further the 0.16% is the fraction of the galactic disk area, not stars. Also note that the 0.16% is the region we could sweep with a theoretical telescope that we might be able to build in the near future, not the region we've actually surveyed thus far.