Re:The Best Way yet to Talk to Aliens, If They’re out There ...
by tjradcliffe on Tuesday January 20, 2015 @02:33PM
(#8918936)
To get a sense of available band-width, old-style TV was 512 x 480 interlaced, so 30 full frames per second, three colours, with about 6 bit resolution per colour, or about 0.5 MB/s. Wikipedia is about 23 GB (text only, including markup). So about 12 hours to transmit the whole thing. Much larger with images, of course.
[I did the calculation this way because back in about 1990 I had the brilliant idea of a satellite that broadcast the sum total of human knowledge to everyone on Earth, and figured out that a single TV channel could basically handle it on a 24 hour cycle, based on what we knew then. Which just goes to show how stupid brilliant ideas can look a short time later...]
While writing this I though of algorithm that might work better to maximize amount of civilizations you reach. This would require a relatively stable space transmitter, or series of coordinated ground transmitters:
1. Pick a set of stars S that potentially can support advanced civilization and are located closely in a region of space (so you do not have to reposition telescope a lot).
2. Start sending signals primer signals to stars. For signal S[x], temporal difference between S[x] and S[x+1] would a set amount shorter than temporal distance between S[x-1] and S[x]. Primer signals are short and cheap, transmitting entire Wikipedia should take way longer (Weeks, months, maybe years?).
3. Once time between primer signals reaches some threshold start transmitting data set.
Idea is that this will give advanced civilization potentially listening a chance to prepare to receive full transmission, while avoiding costly repeats of big data set.