Alfke.PASA@Xerox.ARPA (08/08/85)
From: Peter Alfke <Alfke.pasa@Xerox.ARPA> Dave Newman (Newman.pasa@Xerox) writes: >Any alien in the solar system will notice us on Earth!!! ... >It is very easy to see that something is >happening on Earth if you look at a night-time picture of North >America; you can identify most of the major population centers by >the size and approximate location of the blob of light that sits >there. From a low orbit (i.e. a LandSat satellite, from which we get those pretty pictures) only. From the distance of the moon, such features are invisible. In fact, ALL signs of civilization (except for radio emissions, of which enough has already been said) are invisible. --Peter Alfke
gmp@rayssd.UUCP (Gregory M. Paris) (08/11/85)
> >Any alien in the solar system will notice us on Earth!!! ... > > From a low orbit (i.e. a LandSat satellite, from which we get those > pretty pictures) only. From the distance of the moon, such features are > invisible. In fact, ALL signs of civilization (except for radio > emissions, of which enough has already been said) are invisible. This talk about low orbits is just nonsense. If aliens are going to bother to come all this way to visit our star system, I'm pretty sure they'll take just a little more time to investigate the planets (and probably larger moons as well). More likely, spacefaring aliens are headed toward the galactic hub. There the star densities are much higher, providing richer "ground" for whatever it is they're looking for. -- ++---------------------------------------------------------------------------++ || Greg Paris {allegra,linus,raybed2,ccice5,brunix}!rayssd!gmp || ++---------------------------------------------------------------------------++