3 ms·
Huh? > Only when the sphere’s thin outer shell had reached the earth—perhaps carrying radio signals from the extraterrestrials’ early history, before their rap
by piker 6y ago
Huh?
> Only when the sphere’s thin outer shell had reached the earth—perhaps carrying radio signals from the extraterrestrials’ early history, before their rapid expansion started. By that point, though, the expanding sphere itself would be nearly upon us!
Wouldn't the problematic portion of the sphere be, by definition, millions of years away from us? Given that radio waves travel at the speed of light, and the alien civilization travels at slightly less than the speed of light, it seems like we should have at least however many million years it took for those aliens to get from producing radio waves to "maxing out" travel.
- T-A 6y agoThe first radio transmission by humans was made in 1895. It took another 74 years for humans to land on the moon. It would be disappointing if our augmented and/or artificial descendants really needed millions more years to reach beyond the solar system.
- piker 6y agoRight, but that was sparse and unlikely to be detected, and the author is talking about the portions of the sphere which travel at near speed of light catching up to earth. If human progress is measured on the scale of reaching near-speed-of-light travel, it is easy to imagine being thousands if not millions of years off.