>>> Part 1 of 2...
 
-=> On 02-03-98  13:13, Jack Sargeant said to Ivy Iverson,<=-
-=>"About [1/2] Speculations & fact...,"<=-
-=> On 02-01-98  09:50, Jack Sargeant said to Troy H. Cheek,<=-
-=>"About Speculations...,"<=-
-=> On 27 Jan 98, concerning _Speculations_, Jack Sargeant said to
-=> Charles Daniels in UFO:
 
Hi, Jack;
 
I'm ticked.  I had this reply almost finished, and a power bump came
along and rebooted the computer!   :-<
...
 
 JS> ... A chess game would take longer
 JS> to play than our solar system will last.
 II> True, if it were in another part of the galaxy, however if it were one
 II> of our close neighbors, like Alpha Proxima at 4+ light years, it would
 II> "only" take a little over 8 years to get an answer, (or the next move
 II> in the chess game).
 JS> Well, that would be nice, but somehow, I suspect the grand design of
 JS> things in the universe manages to keep other sentient life just out
 JS> of reach of mankind. We do know that another similar race with similar
 JS> technology is either not interested in us, or is further than 100
 JS> light years away.
 
Where do you get the arbitrary figure of 100 light years?  And for that
matter, what makes you think that it's IMPOSSIBLE for a technology far
more advanced than ours couldn't possibly find a way to travel such
distances within their lifetimes... and for that matter, how long are
THEIR lifetimes?  20 of our years?  50?  100?  200? 500?  Or 1,000???
Different animals native to this planet have different life expectancies.
Some insects only a day or two.  Some birds only a few years, while other
birds can live 150 years or more!  A year-old mouse is ancient, a year-old
elephant is still a baby.  True, the larger an orgganism is the lonter
it lives - as a general rule, however what's the lifespan of a bacteria
so small you need a powerful microscope to see, which keeps dividing as
long as it's viable?
 
 II> At the rate our sociery is deteriotrating, I wonder if we, (the
 II> human race), will still be around in 100 years, let alone 10,000.
 II> :-<
 JS> ...And how far can a radio
 JS> signal travel before the ethers absorb the last weak remainder of
 JS> a broadcast? Our Explorer missions are just now at the outer reaches
 JS> of our own solar system.
 
The hardware has passed the orbit of Pluto, but our radio signals have
traveled over 100 light years away, and our TV signals are over 50 light
years distant!  IF you were 30 light years from Earth and had a large
enough antenna and a sensitive enough receiver, you could be watching
Groucho Marx, "You Bet Your Life" and "I Love Lucy"... and they aren't
re-runs!
 
 II> Yes, and they are using less transmitter power than a flashlight
 II> bulb, and less than a CB (4 watts output).
 JS> Could another civilization tens of thousands of light years away
 JS> still detect our radio emissions?
 II> Yes, if they have radio telescopes equal to ours.
 JS> A distant Pulsar can radiate a signal billions of times stronger than
 JS> the strongest radio signal man has ever broadcast (approx. 200,000
 JS> watts for the strongest radio stations). I don't know what the limits
 JS> are of radio telescopes, but I would guess at about 100,000 watts.
 II> ERROR!  A UHF TV station is limited to one million watts (ERP -
 II> Effective Radiated Power), and there are international broadcast
 II> transmitters, such as the ones used by VOA that exceed that power
 II> level.
 JS> OK by me.
 JS> ...And I doubt if a radio telescope has actually been built that
 JS> can transmit at more than a thousand watts.
 II> Even if the transmitter FEEDING the radio telescope only puts out
 II> 1,000 watts, the antenna has gain, and can focus it into a beam
 II> with the strength, (ERP), of several million watts!
 JS> What is the gain factor of a large dish antenna?
 
The larger the antenna the more the gain.  The largest radiotelescope
antenna on this planet is the one at Aricibo.  Hams have been bouncing
signals off the Moon - and communicating around the world that way -
since the early 1950's, but to do so, they need to have transmitters in
the hundreds of Watts output, fed into very high-gain antenna systems,
giving them ERPs of several tens of thousand watts.  I once knew a fellow
by the name of Virgil Patten, (Ham call: W7KNN), who used the Aricibo
antenna to bounce a signal off the Moon using ONLY 100 MILIWATTS - ONE
TENTH OF A WATT!!!  Does that give you an idea of how much gain a huge
dish can have?  There is a radiotelescope antenna in Canada that is,
IIRC, 100 Meters, (over 300 Ft!), in diameter that was fed by a 1,000
Watt transmitter doing Moonbounce experiments... and with all that gain
on that end of the link, they talked with - and heard - Hams that
could only manage a couple of KW ERP, so would otherwise never
accomplish Moonbounce.  (Thier antenna systems were still impressive, but
not the arrays of 16 or 32 yagis, similar to TV antennas, but containing
200-300 elements each instead of the typical TV deep fringe antennas
containing perhaps 20 elements.)
 
 JS> TV stations that transmit
 JS> to satellites for re-broadcast back to earth certainly don't require
 JS> more than a few thousand watts of focused power. ...Maybe even less
 JS> than a thousand watts.
 
 II> Actually, the ground transmitters which feed "the birds" only use
 II> around 20 watts to the antenna, and IIRC, the transponders in the
 II> "birds" use about 10 watts to cover the entire U.S.  But the dish
 II> antennas that are
 II> used effectively multiply those power levels many times.
 JS> How many times?
 
Often thousands of times.  (See above.)
 
 JS> (A 4 watt CB radio signal can travel about
 JS> 30 miles under perfect conditions, and a few thousand miles under
 JS> "skip" conditions, where the signal can bounce off one of the
 JS> atmospheric layers.
 
About 30 miles max because of the curvature of the Earth!
 
 II> Actually, they are limited by terrain, not distance.  When Sputnik
 II> Jr, the 40-year memorial of the first manmade object in orbit, was
 
 >>> Continued to next message...
 
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