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Arecibo shutdown...

S

Steve Wilson

Guest
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
 
C

Corvid

Guest
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.
 
J

John Doe

Guest
see also...
=?UTF-8?B?8J+QriBDb3dzIGFyZSBOaWNlIPCfkK4=?= <nice@cows.moo>
Banders <snap@mailchute.com>
Corvid <bl@ckbirds.org>
Cows Are Nice <cows@nice.moo>
Cows are nice <moo@cows.org>
Cows are Nice <nice@cows.moo>
dogs <dogs@home.com>
Great Pumpkin <pumpkin@patch.net>
Jose Curvo <jcurvo@mymail.com>
Local Favorite <how2recycle@palomar.info>
Sea <freshness@coast.org>
Standard Poodle <standard@poodle.com>
and others...

--
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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
Organization: The 27 Club
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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.
 
P

Phil Allison

Guest
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
 
M

Martin Brown

Guest
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-phaethon-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.

--
Regards,
Martin Brown
 
P

Phil Allison

Guest
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.
..... Phil
 
S

Steve Wilson

Guest
Martin Brown <\'\'\'newspam\'\'\'@nonad.co.uk> wrote:

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.
+1. Thanks



--
Science teaches us to trust. - sw
 
M

Martin Brown

Guest
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.

** 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.

--
Regards,
Martin Brown
 
T

Tom Del Rosso

Guest
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.
 
T

Tom Del Rosso

Guest
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?
 
R

Rickster C

Guest
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?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209
 
M

Martin Riddle

Guest
On Thu, 19 Nov 2020 20:28:02 -0800 (PST), Phil Allison
<pallison49@gmail.com> 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 ?


..... Phil
No one. Once the little green men found and capruted Jan, they took
a hyperspace jump back to Omicron Persi 8.

Cheers
 
B

bob prohaska

Guest
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




 
B

bitrex

Guest
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>
 
B

bitrex

Guest
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
The reply from even a Type I civilization (which is far more advanced
than ours), that wished to communicate, would not be subtle when it
arrives. The ability of a civilization to pull signals out of the noise
and return the call massively amplified likely scales with the civilization.

If and when a civilization like that picks up our lil signal and they
decide they have something to say in response, when the reply come back
no one\'s going to be mistaking it for anything other than what it is.
 
B

bitrex

Guest
On 11/20/2020 7:47 AM, Martin Brown wrote:
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.

**   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.
Finding other civilizations like our own in say a 100 light year volume
is mostly hopeless over the bulk of the volume. I think the hope is
always that there\'s a least a type I civilization in there that\'s
converted their entire home planet into a launchpad for colonizing their
solar system or nearby stars and has some radio tech that makes ours
look like bugs to pick our signal out of the noise and call back.

But on the scale of the Galaxy 100 light years is also a tiny volume so
it\'s very much a longshot.
 
B

bitrex

Guest
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
 
B

bob prohaska

Guest
bitrex <user@example.net> wrote:
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?
My mistake, communications was a dumb constraint 8-(

Let\'s just suppose we\'re searching for a signal, from somebody with instruments
like ours. No constraint on when they did the sending, could be a billion years
ago. Easy case first, we happen to guess right on which direction to look and
what kind of signal they are sending. How far away could they be and still have
enough \"brightness\" against the background noise to be recognized using 50 years
of receiver data?

Probably there should be a constraint on the baud rate, but I\'m not sure how
to word it. Maybe ten bits with 95% confidence? It does seem intuitive that
fast signals are harder to recognize than slow.....

Thanks for reading,

bob prohaska





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
 
T

Tom Del Rosso

Guest
bitrex wrote:
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
You don\'t like our part of the galaxy? You\'d rather be closer to the
black hole?

BTW Biden has several mansions too; he just didn\'t earn them by building
anything.
 
T

Tom Del Rosso

Guest
Rickster C wrote:
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?
After further consideration I suppose it would be about the same, just
more above the ecliptic and less below..
 
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