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Arecibo Observatory Collapsed

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Re: Arecibo Observatory Collapsed

#231

Post by voldacar »

mumblemumble wrote: post #97
skuhn wrote: post #59

Earlier quoted context omitted.

I agree that the impact of Arecibo and these kinds of installations is actually very outsized relative to the number of FTE employees who directly work on it. The larger scientific community are the ones who booked time on the telescope after all. My point is that politically none of that matters. No one is getting elected because people got to book telescope time for their research. The incentives are not correctly…

> So the F-35 makes jobs... I wonder about that. It's been a while since I studied, but the phrase "deadweight loss" looms large in what I remember of the one economics class I took in college. So I wouldn't be surprised if the program is actually a net negative for job creation. Only that doesn't matter, either, because the point is not to create more jobs; the point is to influence job creation in a way that benefi…

Unless the actual physical F35 planes end up delivering some kind of value to their purchasers (let's face it, they basically won't), funding the F35 is a lot like breaking Bastiat's window. It's a case of the seen vs the unseen, which is why so few are equipped to complain about it

Re: Arecibo Observatory Collapsed

#232

Post by vxNsr »

NovemberWhiskey wrote: post #131
vxNsr wrote: post #123

Earlier quoted context omitted.

PR residents are actively against the idea mainly because they don't pay fed taxes. only reason democrats are for the idea is because they believe it'll give them another two reliable seats in the senate.

PR residents voted in favor of statehood in a referendum[0] in the most recent election cycle. 52.34% voted in favor, based on a turnout of 52%. [0] https://en.wikipedia.org/wiki/2020_Puerto_Rican_status_refer...

well that's new.... I was there back in 2017 and everyone I spoke to was very against it, and I remember when I looked up the stats they also showed the majority weren't for it. Still looks like it's a close issue, statehood is a big deal and affects everyone dramatically, kinda feel like it should have overwhelming support, not 51% of 52% of ppl... that's actually only 26% of eligible voters voting for it.

Re: Arecibo Observatory Collapsed

#233

Post by vxNsr »

fweespeech wrote: post #171
vxNsr wrote: post #123

Earlier quoted context omitted.

PR residents are actively against the idea mainly because they don't pay fed taxes. only reason democrats are for the idea is because they believe it'll give them another two reliable seats in the senate.

https://www.vox.com/policy-and-politics/2017/10/4/16385658/p... . > Puerto Rico is a US territory and not a state, so its residents don’t pay federal income tax unless they work for the US government. Even so, workers there pay the majority of federal taxes that Americans on the mainland pay — payroll taxes, social security taxes, business taxes, gift taxes, estate taxes and so on. https://en.wikipedia.org/wiki/List_…

Your argument basically boils down to: well they do pay some tax so they can pay more anyways... not a great argument.

Re: Arecibo Observatory Collapsed

#234

Post by NovemberWhiskey »

vxNsr wrote: post #232
NovemberWhiskey wrote: post #131

Earlier quoted context omitted.

PR residents voted in favor of statehood in a referendum[0] in the most recent election cycle. 52.34% voted in favor, based on a turnout of 52%. [0] https://en.wikipedia.org/wiki/2020_Puerto_Rican_status_refer...

well that's new.... I was there back in 2017 and everyone I spoke to was very against it, and I remember when I looked up the stats they also showed the majority weren't for it. Still looks like it's a close issue, statehood is a big deal and affects everyone dramatically, kinda feel like it should have overwhelming support, not 51% of 52% of ppl... that's actually only 26% of eligible voters voting for it.

Would you believe, almost exactly the same proportion of the U.S. electorate that voted for Donald Trump in 2016?

Re: Arecibo Observatory Collapsed

#235

Post by packetslave »

olsonjeffery wrote: post #76
dmurray wrote: post #41

Earlier quoted context omitted.

Well, there was a bit of incompetence. The auxiliary cable was almost certainly installed incorrectly and the failure mode that occurred (cable slipped out of its socket) would not have happened if best practices were followed. But it was installed on the cheap: if they'd had more money they would likely have paid for more diligent engineers. After all, they built it pretty well the first time round. So at some level…

>Well, there was a bit of incompetence. Where? What evidence do you have for such a claim? >The auxiliary cable was almost certainly installed incorrectly Are you almost certain? How do you know? What stopped you from being completely certain? >and the failure mode that occurred (cable slipped out of its socket) would not have happened if best practices were followed. Are you a radio observatory specialist? Please sh…

why are you so angry?

Re: Arecibo Observatory Collapsed

#236

Post by est31 »

NikolaeVarius wrote: post #228
est31 wrote: post #88

I've wondered about the exact time of the collapse. Apparently there is a seismic observatory only tens of meters away from the telescope dish. The station code is AOPR [0]. After retrieving the mseed data from the web API using curl, and installing obspy from pip, I could plot the events. This is the result: [1]. You can see two "events". One at Nov 30, 23:12 UTC, and a second, larger one at Dec 1st, 11:52 UTC. Upon…

According to this Scott Manley video there was an earthquake in the Dominican Republic that may have been responsible for the break. Timing matches up. Trying to find his source https://www.youtube.com/watch?v=vchDbyIRP44

In the video he shows a screenshot from facebook while mentioning the earthquake. I dug it up, seems to be this post: https://www.facebook.com/redsismicadepuertorico/photos/a.101...

> The Puerto Rico Seismic Network (PRSN) is saddened to learn about the collapse at the Arecibo Radiotelescope Observatory this morning of December 1st, 2020. PRSN’s seismic station AOPR, located within the premises of the observatory, detected the timing of the failure. This seismic station has been a long collaboration between PRSN and the Arecibo Observatory. Here we publish the seismic record of AOPR at the time of collapse, which coincidentally occurred during the passage of seismic waves through Puerto Rico from a Dominican Republic earthquake of M4.0 that occurred at 07:51 AM AST. The figure below shows 07:52:42 AM AST (11:52:42 UTC) as the exact time of collapse at the AOPR seismic station, denoted by a sharp impulsive signal, right after the arrival of the S wave of the earthquake. It is a sad day for Science and a tragedy to lose such an important, iconic, valuable, and unique scientific instrument and allowed so many scientific advances and discoveries to humanity.

That facebook post is waaaay better than what I as a layman was able to come up in the post above. We made both posts at the same time though, so I couldn't know any better.

Also thanks for posting the link to the video, it's precisely the kind of breakdown I like :).

Re: Arecibo Observatory Collapsed

#237

Post by knaq »

ajford wrote: post #149
z2 wrote: post #100

Earlier quoted context omitted.

Not to defend incompetence, but could the design have made it a bit unwieldy with the 900 (US) ton receiver housing the array of focusing lenses/mirrors? Is it common enough to suspend something that massive from so few points? The only comparison I know is the FAST which opted to actively deform the dish itself for focusing rather than suspend such a heavy receiver.

The original platform didn't include the Gregorian dome. The auxiliary cables were added in the mid 90s during a major upgrade that included the dome, adding a considerable amount of weight. The choices were made based on funding and ability. The main platform, towers, and reflector was designed and constructed in 1960, long before our computing capabilities could have even conceived of being able to accurately defor…

In lots of telescope designs, the sensor is behind the dish. The part in front of the dish is only a reflector. Done that way, weight of a transmitter doesn't matter.

Re: Arecibo Observatory Collapsed

#238

Post by kaikai »

dheera wrote: post #229
petschge wrote: post #220

Earlier quoted context omitted.

The cables were (originally) redundant. There are actually replacement cables on the way from Germany right now. But after the one main cable failed earlier this year they noticed that all cables are MUCH weaker than previously thought. So there was (even before the collapse) no way of replacing the existing cables with the replacements. And yes that probably implies that they should have swapped out all cables years…

> no way of replacing How did they build the cables in the first place? Couldn't they just snip the cables with a helicopter or unmanned drone with a flying chopsaw and string new ones as if it was a brand new construction? Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something.

Being unable to fix something you’re able to build isn’t unusual to anyone who has built a large and complicated structure. They had two different engineering firms look at it, and neither of them saw a safe path forward. It’s possible that repairing it was physically possible, but would have put people in harms way while they were, for example, detaching cables on an already unstable structure.

Re: Arecibo Observatory Collapsed

#239

Post by paledot »

dheera wrote: post #229
petschge wrote: post #220

Earlier quoted context omitted.

The cables were (originally) redundant. There are actually replacement cables on the way from Germany right now. But after the one main cable failed earlier this year they noticed that all cables are MUCH weaker than previously thought. So there was (even before the collapse) no way of replacing the existing cables with the replacements. And yes that probably implies that they should have swapped out all cables years…

> no way of replacing How did they build the cables in the first place? Couldn't they just snip the cables with a helicopter or unmanned drone with a flying chopsaw and string new ones as if it was a brand new construction? Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something.

The dish is nothing but aluminum sheeting with holes in it. The vast majority of the cost and complexity are in the instrument cluster and the towers. There's not much of value left to repair at this point.

As for replacing cables, anyone who has rebuilt a RAID array will tell you that hardware is most likely to fail when it's under stress, like when you have workers in the towers setting the footings for the new ultra-safe cables. It's not just dangerous because they don't know when it'll give way, it's dangerous because messing with it was likely to trigger a collapse like what we just saw.

Re: Arecibo Observatory Collapsed

#240

Post by dredmorbius »

paledot wrote: post #239
dheera wrote: post #229

Earlier quoted context omitted.

> no way of replacing How did they build the cables in the first place? Couldn't they just snip the cables with a helicopter or unmanned drone with a flying chopsaw and string new ones as if it was a brand new construction? Basically I'm not understanding how it is impossible to replace something but it is evidently possible to build that something.

The dish is nothing but aluminum sheeting with holes in it. The vast majority of the cost and complexity are in the instrument cluster and the towers. There's not much of value left to repair at this point. As for replacing cables, anyone who has rebuilt a RAID array will tell you that hardware is most likely to fail when it's under stress, like when you have workers in the towers setting the footings for the new ult…

The location itself, both in terms of terrain and extant infrastructure and personnel also has value. Without the dish to support it, that's also a writeoff.

Still likely not a compelling case for rebuilding, however.

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