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Arecibo Observatory Collapsed

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Re: Arecibo Observatory Collapsed

#21

Post by Rooster61 »

Macha wrote: post #19
Rooster61 wrote: post #18

So, one thing that isn't clear to me. They were already planning to decommission the structure, so was this a planned collapse, or did this happen literally right after their announcement by coincidence? If its the latter, I'm very glad they made the call to not try to fix this thing. It would have been so much more tragic had someone been up on the sub-reflector/instrument assembly. Good call by the powers that be t…

My understanding is the fact that this was possible (even likely) was why they decided not to attempt repairs. Basically, the second cable should not have snapped if it was still at design strength, so its failure put the strength of the others (and hence the entire structure) in doubt.

I might not have been clear in my comment. I understand why they didn't go up and repair it. I just wasn't sure if if they decided to go ahead and demo it or if it fell under its own weight just a week or so after they decided to not try to fix it.

That much isn't clear from the articles I have been able to find through a quick google.

Re: Arecibo Observatory Collapsed

#22

Post by javajosh »

VLM wrote: post #14
est31 wrote: post #4

I've heard that radio astronomy was greatly supported by the military because it can be used to monitor for incoming ICBMs. I guess if Arecibo were still used for such purposes, they wouldn't have let it fall into disrepair. How is such monitoring conducted in this day and age?

It went thru the journalist filter a million times until unrecognizable. The first answer is ICBMs are, now a days, mostly an IR optical thing. The flightpath of most Russia to US ICBMs would never have passed over the observatory, obviously, but it was a major radar technology research site in the early years.

>The first answer is ICBMs are, now a days, mostly an IR optical thing.

Source? This seems unlikely since ground-based visual tracking would be obscured by e.g. clouds. Is ICBM tracking all space-based and visual? (I can see why IR is useful to detect the initial boost, but it would also seem rather useless to track a small, passive object in freefall).

Re: Arecibo Observatory Collapsed

#23

Post by rjmunro »

Is this picture real? I don't get why there isn't any evidence of bits of cables still hanging from at least one of the towers or any other kind of wreckage. It looks more like someone has photoshopped all the cables out of of an old photo.

Re: Arecibo Observatory Collapsed

#24

Post by Macha »

Rooster61 wrote: post #21
Macha wrote: post #19

Earlier quoted context omitted.

My understanding is the fact that this was possible (even likely) was why they decided not to attempt repairs. Basically, the second cable should not have snapped if it was still at design strength, so its failure put the strength of the others (and hence the entire structure) in doubt.

I might not have been clear in my comment. I understand why they didn't go up and repair it. I just wasn't sure if if they decided to go ahead and demo it or if it fell under its own weight just a week or so after they decided to not try to fix it. That much isn't clear from the articles I have been able to find through a quick google.

Every article I've found indicates it was an unintentional collapse, but they're mostly sourced to the unidentified "officials and locals" from the AP report, which may just be the original tweet and replies.

EDIT: NSF confirms it was an unplanned collapse that happened overnight: https://twitter.com/NSF/status/1333772980539691008

Re: Arecibo Observatory Collapsed

#25

Post by est31 »

VLM wrote: post #14
est31 wrote: post #4

I've heard that radio astronomy was greatly supported by the military because it can be used to monitor for incoming ICBMs. I guess if Arecibo were still used for such purposes, they wouldn't have let it fall into disrepair. How is such monitoring conducted in this day and age?

It went thru the journalist filter a million times until unrecognizable. The first answer is ICBMs are, now a days, mostly an IR optical thing. The flightpath of most Russia to US ICBMs would never have passed over the observatory, obviously, but it was a major radar technology research site in the early years.

Hmm ok I watched the video someone else linked here, apparently the telescope was used to check for facilities in Russia by checking the reflection of radio waves on the moon. Pretty cool stuff.

Re: Arecibo Observatory Collapsed

#26

Post by bayindirh »

rjmunro wrote: post #23

Is this picture real? I don't get why there isn't any evidence of bits of cables still hanging from at least one of the towers or any other kind of wreckage. It looks more like someone has photoshopped all the cables out of of an old photo.

You're right but, it looks like the smoke/dust comes from the anchor points of the cables, so the ground part gave way and all cables were collapsed cleanly.

Another angle is https://twitter.com/adamonzon/status/1333742939005218816/pho...

Also looks like "cable hubs" at the top of support towers are gone too.

Re: Arecibo Observatory Collapsed

#27

Post by [deleted] »

rjmunro wrote: post #23

Is this picture real? I don't get why there isn't any evidence of bits of cables still hanging from at least one of the towers or any other kind of wreckage. It looks more like someone has photoshopped all the cables out of of an old photo.

[deleted]

Re: Arecibo Observatory Collapsed

#30

Post by Arubis »

m000 wrote: post #16

"Too big to fail" apparently doesn't apply for science projects. To put this in perspective, at the cost of a single F-35A, Arecibo could be running for ~7y with funding at 2011 levels.

And, unlike an F-35A, Arecibo has (sigh, _had_) a history of accomplishing its design goals.

RIP.

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