Re: OT: Aliens in the heavans (was Re: seti@home)
On Tue, 2002-03-05 at 17:19, Gary Hennigan wrote:
> "Ron Johnson" <ron.l.johnson@cox.net> writes:
> > On Tue, 2002-03-05 at 14:13, Gary Turner wrote:
> > > I've been running setiathome on my winboxes and am considering adding my
> > > linbox to the mix. So, the question is what is the appropriate
> > > directory to unpack and run this little bippy? How does the graphical
> > > mode do?
> >
> > Have you looked at http://www.distributed.net? Instead of scanning
> > the sky for aliens broadcasting into the heavens, it tries to brute-
> > crack an RC5-64 cypher.
> >
> > P.S. - If we expect _others_ to broadcast, why don't we broadcast
> > in all directions around the globe, hoping that someone else hears
> > us?
>
> Hate to tell ya this but we broadcast straight out to the heavens
> constantly. That's how we uplink to satellites. You realize that the
> radio signals we send out to those birds aren't exactly like a laser
> beam, right? Even the narrowest-beam radio-frequency broadcast, aimed
> with extreme accuracy at the intended satellite, is going to "spill"
> quite a bit out to space. Think about satellite TV systems. One bird
> in space can cover a lot of ground on the Earth's surface. Same
> prinicipal in the opposite direction.
Yes, yes, all those TV, radio stations, satelite uplink stations
(the vast majority all of which are in the Northern Hemisphere)
are radiating outwards.
However, since you know full well the, well, astronomical,
distances involved, and given that radiation strength drops as
a cubic (since waves go out in 3 dimentions) function as distance
increases, I have a question:
If most stars need telescopes (even the Hubble) to see them,
and they radiate jillions^3 of watts on energy, and still look
like pin-pricks, how could the signal from a 50,000 watt radio
station, or a 250,000 watt TV station (both of whose signals
are absorbed somewhat by the air) reach an antennae 20 light
years away, while passing through all that background noise?
Since I've been wrong more than once, please tell me what I'm
missing.
> Not only that, but there's probably a lot of omni-directional antennas
> in use for surface-to-surface broadcasts as well. This means they send
> as much signal straight up as they do to surface targets. I'm
> simplifying it a lot (mainly because it's been so long since I studied
> this stuff), but suffice it to say we "leak" a *LOT* of radio signal
> out into space. It's safe to assume that any other civilizations out
> there, with of the same technological means, do the same and I'm sure
> that's what SETI is targeted at finding.
>
> There are plenty of reasons to question the worth of the SETI project,
What are they?
> just not on the grounds that an alien civilization would have to
> intentionally broadcast a signal to us for us to detect it.
Not to US, but just out in _EVERY_ direction, since that alien civ
doesn't know in what direction the receiving civ is.
> Of course if you're being sarcastic then I just wasted too much time
> replying, and you need to use smileys! :)
Well, no, not sarcastic, just of a different religion. I prefer to
waste my cycles trying to brute-force crack a 64-bit cypher. Since
it's been going for ~3 years now, any rational person should deduce
that brute-force cracking RC5-64 is a BIG waste of time...
--
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| Ron Johnson, Jr. Home: ron.l.johnson@cox.net |
| Jefferson, LA USA http://ronandheather.dhs.org:81 |
| |
| 484,246 sq mi are needed for 6 billion people to live, 4 !
! persons per lot, in lots that are 60'x150'. |
! That is ~ California, Texas and Missouri. !
! Alternatively, France, Spain and The United Kingdom. |
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