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"But present day human civilization on earth would in fact be entirely invisible to a human-level civilization even one star over." Really? I find that surpris
by p_zakharov 10y ago
"But present day human civilization on earth would in fact be entirely invisible to a human-level civilization even one star over."
Really? I find that surprising. On a related note:
http://www.lightyear.fm/ http://www.lightyear.fm/
- joe_the_user 10y agoRadio energy dissipates by square of the distance to a location - essentially as a transmission expands, the same amount of energy is spread evenly around a sphere of increasing area. Area of a sphere centered at the sun and encompassing the nearest star is vast.
- p_zakharov 10y agoOh yeah, true that, I thought the signal would be faint several light years out for omnidirectional signals, like FM radio and TV, I just didn't think it would be undetectable. I mean I assume that Contact was pretty scientifically tenable and that had aliens sending back transmissions of Adolf Hitler on television and that was over a much greater distance, but I'm willing to change this belief. This, BTW, is why I am strongly in favor of optical SETI.
- deleted 10y ago[deleted]
- goodcanadian 10y agoI'm too lazy to google a source right now, but actually, yes, we could detect Earth out to a few tens of lightyears. Not far in the scale of things, and the only thing we'd really be able to detect are the most powerful radars, but it is theoretically possible to detect ourselves at nearby stars.