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Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
-- Science teaches us to trust. - sw
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From: Corvid <bl@ckbirds.org
Newsgroups: sci.electronics.design
Subject: Re: Arecibo shutdown
Date: Thu, 19 Nov 2020 18:04:53 -0800
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On 11/19/2020 02:56 PM, Steve Wilson wrote:
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
I followed links from there to a much bigger and shinier radio telescope
in China, apparently finished and ready, but nobody wants to work there.
-- Science teaches us to trust. - sw
Claude Bernard is a piece of shit.
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
Steve Wilson wrote:
z.
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
They only did a tiny amount of that.
Though they did once transmit a
signal for the LGM towards M13 back in the Carl Sagan days.
** Reply expected, any day now.
On 20/11/2020 04:28, Phil Allison wrote:
Steve Wilson wrote: z.
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to
-be- decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
They only did a tiny amount of that. Though they did once transmit a
signal for the LGM towards M13 back in the Carl Sagan days.
https://en.wikipedia.org/wiki/Arecibo_message
Probably not a good choice since although there are plenty of stars
there the stellar dynamics make solar systems less likely.
Recent work includes some impressive radar imaging and ranging of the
Near Earth Asteroids. Arecibo does its radar imaging with impressive
results. They can transmit and receive with a very narrow time gating.
https://www.nasa.gov/feature/jpl/arecibo-radar-returns-with-asteroid-ph
aethon-images
https://www.naic.edu/~pradar/press/2017YE5.php
Their collimated radar beam is quite wide though but the timing gate
to resolve surface detail is very narrow. The second link is very
pretty.
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Martin Brown wrote:
================
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
They only did a tiny amount of that.
** What about Ellie Arroway ?
Though they did once transmit a
signal for the LGM towards M13 back in the Carl Sagan days.
** Reply expected, any day now.
Taking potshots at nearby F,G,K type stars is a much better bet iff we
want to be noticed as non-thermal radiation. For the period where we
had high power radars and analogue TV we were obvious to anyone
looking for interesting signals with a sensitive enough radio
telescope.
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if was
also a stationary dish. Why did we put it in Puerto Rico?
Steve Wilson wrote:
z.
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
..... Phil
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if was
also a stationary dish. Why did we put it in Puerto Rico?
Tom Del Rosso <fizzbintuesday@that-google-mail-domain.com> wrote:
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if was
also a stationary dish. Why did we put it in Puerto Rico?
Probably, cost. It\'s built into a natural cavity in the ground. I believe
the new Chinese instrument is constructed similarly.
An aside: Over what distance could two Arecibo-like instruments communicate if
A) they knew where to look and what to look for
B) they knew only where to look, but not what to look for
C) They knew not where to look and not what to look for
D) they knew not where to look, but did know what to look for
The answers doubtless depend on time allocated to the search.
Let\'s assume 50 years, the approximate life of the instrument.
I\'ve done a little web-surfing and found no explicit discussions.
The answers might have some bearing on Fermi\'s paradox.
Thanks for reading and any insights,
bob prohaska
Tom Del Rosso <fizzbintuesday@that-google-mail-domain.com> wrote:
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if was
also a stationary dish. Why did we put it in Puerto Rico?
Probably, cost. It\'s built into a natural cavity in the ground. I believe
the new Chinese instrument is constructed similarly.
An aside: Over what distance could two Arecibo-like instruments communicate if
A) they knew where to look and what to look for
B) they knew only where to look, but not what to look for
C) They knew not where to look and not what to look for
D) they knew not where to look, but did know what to look for
The answers doubtless depend on time allocated to the search.
Let\'s assume 50 years, the approximate life of the instrument.
I\'ve done a little web-surfing and found no explicit discussions.
The answers might have some bearing on Fermi\'s paradox.
Thanks for reading and any insights,
bob prohaska
On 20/11/2020 11:10, Phil Allison wrote:
Martin Brown wrote:
================
Arecibo has reached EOL.
https://arstechnica.com/science/2020/11/famed-arecibo-observatory-to-be-
decommissioned-in-wake-of-cable-breaks/
** So who is listening for \"little green men\" now ?
They only did a tiny amount of that.
**Â Â What about Ellie Arroway ?
The last time they thought they saw an artificial signal it was almost
certainly a geostationary satellite sat in a sidelobe. Confirmation
observations with other instruments didn\'t see the same thing. eg.
https://www.seti.org/signals-nearby-star-system
Can\'t blame them for trying every now and then. Receivers have got a lot
more sensitive than when I was in that game. They have pretty much kept
up with the weakening signals from the Voyager probes. Now operating as
the fastest and most distant man made objects from the Earth
Though they did once transmit a
signal for the LGM towards M13 back in the Carl Sagan days.
 ** Reply expected, any day now.
Give or take 44.4k years for a round trip. Good publicity at the time
but it would have to be someone serendipitously on the line of sight
path to M13 that replied for us to see it today (and at most 20ly away).
Taking potshots at nearby F,G,K type stars is a much better bet iff we
want to be noticed as non-thermal radiation. For the period where we had
high power radars and analogue TV we were obvious to anyone looking for
interesting signals with a sensitive enough radio telescope.
Martin Brown wrote:
Taking potshots at nearby F,G,K type stars is a much better bet iff we
want to be noticed as non-thermal radiation. For the period where we
had high power radars and analogue TV we were obvious to anyone
looking for interesting signals with a sensitive enough radio
telescope.
The change to digital TV will be misinterpretted somewhere, someday, as
the end of our civilisation, when in fact it was the beginning of a new
era of reruns from TV\'s golden age.
On 11/20/2020 1:38 PM, bob prohaska wrote:
Tom Del Rosso <fizzbintuesday@that-google-mail-domain.com> wrote:
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if was
also a stationary dish. Why did we put it in Puerto Rico?
Probably, cost. It\'s built into a natural cavity in the ground. I believe
the new Chinese instrument is constructed similarly.
An aside: Over what distance could two Arecibo-like instruments communicate if
A) they knew where to look and what to look for
B) they knew only where to look, but not what to look for
C) They knew not where to look and not what to look for
D) they knew not where to look, but did know what to look for
The answers doubtless depend on time allocated to the search.
Let\'s assume 50 years, the approximate life of the instrument.
I\'ve done a little web-surfing and found no explicit discussions.
The answers might have some bearing on Fermi\'s paradox.
Thanks for reading and any insights,
bob prohaska
25 light years out and 25 light years back, assuming you got an
immediate reply?
Then number of star systems within 25 light years isn\'t large. I think
it may be indirectly confirmed there\'s no advanced technological
civilizations on any of \'em we would have heard them by now.
https://en.wikipedia.org/wiki/List_of_star_systems_within_20%E2%80%9325_light-years
\"Horowitz and Sagan (1993), reporting the
results of a five year all-sky survey, concluded
that there are no Kardashev (1964) Type I civilizations (isotropically
transmitting ?10^13 W) within 25 light-years of the Sun, no Type II
within 2500 light years....and those bounds should be tightened
considerably in the coming years\"
https://academic.oup.com/astrogeo/article-pdf/38/4/24/600459/38-4-24.pdf
On 11/20/2020 7:53 AM, Tom Del Rosso wrote:
Martin Brown wrote:
Taking potshots at nearby F,G,K type stars is a much better bet iff
we want to be noticed as non-thermal radiation. For the period
where we had high power radars and analogue TV we were obvious to
anyone looking for interesting signals with a sensitive enough radio
telescope.
The change to digital TV will be misinterpretted somewhere, someday,
as the end of our civilisation, when in fact it was the beginning of
a new era of reruns from TV\'s golden age.
If the Galaxy is the size of one of Trump\'s mansions humanity has
effectively searched a postage-stamp sized area in one of the toilet
bowls for other residents
On Friday, November 20, 2020 at 8:01:11 AM UTC-5, Tom Del Rosso wrote:
Martin Brown wrote:
It is a shame to lose a grand old instrument even if it could only
look at a fraction of the sky around the zenith it was a *very* big
dish.
Something farther from the equator could scan a lot more sky even if
was also a stationary dish. Why did we put it in Puerto Rico?
Really? How does that work exactly?