How smart are SETI@homers?

"Rich" wrote in message
...

Snip

Or is this like Economics where you can get everything wrong for your
entire professional career and still get paid. And if an economist does
get something right one sunny day, it's Nobel prize work for sure.


(While not 100% germane to the above discussion, I just can't resist this
opening)

And if you laid all the economists in the world, end-to end, head-to-toe,
they still couldn't reach a conclusion! :-)

(O.K. - Back on topic)
--
StratR

Rich wrote:

To make your analogy more similar to the situation with SETI you'd have
to use bigfoot or perhaps the Lock Ness Monster.

Now, no matter how many nessie photos are shown to be fake, no matter
how many sonar surveys come up empty, no matter how many fish surveys
show too few fish to feed a breeding population of animals of Nessie's
purported size, the searches continue, with better and better equipment,
and they continue to come up empty.

At what point would an intelligent observer call it quits?

With SETI, we seem doomed to a similar situation.

There is one more problem: microwave beams have to be narrow
to provide enough energy density for distant receivers.
Stars and planets are in constant motion, so unless the ET
aims the beam at us for a long time, we will hear only a few
beeps. It will be difficult to tell if this was a signal from
the ET or a sophisticated prank. Science cannot deal with such
erratic data -- it needs artifacts which can be studied in
many ways for a long time. Even if we get megabytes of data
from a single ET, we cannot determine its veracity and we
cannot ask questions unless they understand our language.

A reusable flyby probe is a more reliable SETI method. The
probe can explore extrasolar planets and tell us a lot about
evolution of extraterrestrial life. It flies at about 0.2% of
the speed of light and takes advantage of gravity assist.
It flies so close to a star that gravity deflects its
trajectory by a large angle and guides it towards next star
flyby.

Andrew Nowicki wrote:

A reusable flyby probe is a more reliable SETI method. The
probe can explore extrasolar planets and tell us a lot about
evolution of extraterrestrial life. It flies at about 0.2% of
the speed of light and takes advantage of gravity assist.
It flies so close to a star that gravity deflects its
trajectory by a large angle and guides it towards next star
flyby.


While I can see where you are coming from I think there is one fly in your
ointment:-

How long would your probe take to get to the nearest star ( not ours ) and
how long would the findings take to get back here and then if no ET found
the time to get to next suitable system?

What would be the cost of dev and launch and monitoring of said probe?

Who would fund it?

Would you not be putting all your eggs in one basket ( target sun system ) ?

--
Mark
Iligitimi Non Carborundum!
Twixt hill and high water, N.Wales, UK
onfxvgpnvfr-ng-tzk-qbg-pb-hx

Andrew Nowicki wrote:

SETI@homers ignore their
failures and have little if any interest in
modifying their search method.

What failure?

Worse yet, they
seem to believe that some extraterrestrial
civilizations have been sending powerful
microwave beams toward the Earth for millions
of years. Why would the extraterrestrial tax
payers support such an effort?

Why should potential extraterrestial civilizations have a tax system, or
currency at all?

What the SETI@home system has shown us, is that there are no earth-like(in
terms of electromagnetic broadcast) inhabited system within a distance of
about 400 light years. There are no alien civilisations deliberately
beaming messages aimed at us within about 5000 light years.

This means we know with reasonable certainty that the local 0.000000001
percent of our galaxy does not contain an earthlike civilisation at this
moment in time.

And people consider that as *proof* that extraterrestrial life doesnt
exist?????

Thats like looking at a square inch of the tarmac in your driveway, and
basing on the shorage of whales visible in your sample the conclusive proof
that whales can not possibly exist!

In infinite wisdom Marvin answered:
What the SETI@home system has shown us, is that there are no earth-like(in
terms of electromagnetic broadcast) inhabited system within a distance of
about 400 light years. There are no alien civilisations deliberately
beaming messages aimed at us within about 5000 light years.

This means we know with reasonable certainty that the local 0.000000001
percent of our galaxy does not contain an earthlike civilisation at this
moment in time.

And people consider that as *proof* that extraterrestrial life doesnt
exist?????

Interesting. So far you are the only one to use the word "proof".

You can't respond to what others post so you invent arguments you think
you can rebut.

Let me ask you this. Whether ET civilizations exist or not, what do you
think our changes of detecting them are?

Say we search for 10,000 years, do you think this will increase our
chances?

Thats like looking at a square inch of the tarmac in your driveway, and
basing on the shorage of whales visible in your sample the conclusive proof
that whales can not possibly exist!

You can tilt at all the windmills you feel it necessary to construct,
but if you ask me, you should feel really stupid for doing so.

Proof is for mathematics.

Evidence is for the real world, and unless you are a UFO buff, their
ain't any and there is no reasonable expectation that any SETI search
will generate any. I consider negative evidence as worth having, but
not as an infinite resource sink.

So my question is, what's the point? Don't we have better uses for
our resources?

How much are you willing to spend? How much of your own money have you
spent?

Rich

Andrew Nowicki wrote in message ...
[Railing at SETI in general...] Worse yet, they
seem to believe that some extraterrestrial
civilizations have been sending powerful
microwave beams toward the Earth for millions
of years. Why would the extraterrestrial tax
payers support such an effort?

This is a reasonable question. Why look for a signal that no one is
motivated to send? However, it turns out this signal is not very
expensive to transmit. (see the appendix on beacon construction in the
book SETI 2020.) If you target your beam so it only covers the
targeted solar system, it takes less than 1 watt per system covered.
So for 1 MW of power, costing at current rates about $700,000 per
year, you could hit each of the nearest 1 million stars with a beam
strong enough that we ourselves could detect it. Although building
the transmitter costs somewhat more, it's still on the order of
existing SETI expenditures.

So transmitting need not be a government activity. It could be easily
funded by the SETI Institute, any number of religious missionary
organizations, or any of thousands of wealthy private individuals. We
should keep this in mind should we ever get a message.

Lou Scheffer

Andrew Nowicki wrote in message ...
Rich wrote:
There is one more problem: microwave beams have to be narrow
to provide enough energy density for distant receivers.
Stars and planets are in constant motion, so unless the ET
aims the beam at us for a long time, we will hear only a few
beeps.

This is not a serious problem. The distance to the stars, and their
proper motions, are well enough known (or will be soon, within
decades) that there is no problem predicting where they will be when
the signal gets there. Also it makes sense to make the beam no
smaller than about 10 AU in diameter at the target system (since there
is no guarantee that the telescope is on one of the planets, for
example), so the beam will not fade in and out as a result of the
target planet's motion. So if we receive it once, and it's
deliberate, it should be easy to receive again.

Lou Scheffer

Marvin wrote in message ...
What the SETI@home system has shown us, is that there are no earth-like(in
terms of electromagnetic broadcast) inhabited system within a distance of
about 400 light years. There are no alien civilisations deliberately
beaming messages aimed at us within about 5000 light years.

This is not correct. SETI@home (or any other SETI so far) is not
sensitive enough to detect a civilization radiating like ours from
*any* star, even the nearest. They all need a much stronger signal,
presumably deliberately aimed our way, to have any chance of
detection. So what SETI@home has shown so far is that after a search
of 1/3 of the sky, no one is sending us strong signals and constant
signals in that particular frequency band (perhaps 1/100 of the best
frequencies). So we don't have any sort of a strong negative yet.

Lou Scheffer

Andrew Nowicki wrote:
Worse yet, they seem to believe that some extraterrestrial
civilizations have been sending powerful microwave beams
toward the Earth for millions of years. Why would the
extraterrestrial tax payers support such an effort?

Lou Scheffer wrote:
This is a reasonable question. Why look for a signal that no one is
motivated to send? However, it turns out this signal is not very
expensive to transmit. (see the appendix on beacon construction in the
book SETI 2020.) If you target your beam so it only covers the
targeted solar system, it takes less than 1 watt per system covered.
So for 1 MW of power, costing at current rates about $700,000 per
year, you could hit each of the nearest 1 million stars with a beam
strong enough that we ourselves could detect it. Although building
the transmitter costs somewhat more, it's still on the order of
existing SETI expenditures.

If we treat the Sun as a black body, intensity of its
microwave radiation at 100 GHz is about 10 million times
smaller than intensity of its visible radiation. The total
visible output of the Sun is on the order of 10^17W, so the
total microwave output of the Sun is on the order of 10^10W.

If the ET lives near a sun-like star and beams to us 1 watt
of microwave signals, his star makes so much microwave noise
that we cannot read the signal unless one beep lasts at least
10^10 seconds (about 300 years).

The signal-to-noise ratio improves 3 orders of magnitude
when the ET's microwave transmitter is moved away from
their star. If the ET replaces his microwave transmitter
with a laser and moves it away from his star, the
signal-to-noise ratio improves at least 20 orders of
magnitude, if we ignore the noise made by our Sun and
terrestrial atmosphere. Moving the laser away from the
star creates a problem: we have to guess where it is.
The natural place for the laser is dark side of a
large, conspicuous planet.