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 closer inspection, the first event is actually multiple smaller ones, not sure if they are related to the collapse at all. The second event is clearly one discrete thing though. The image was uploaded to twitter at 11:56 UTC, so minutes within the collapse being recorded on the seismograph. You can still see the dust in the air.
Pretty cool that all this data is out there, in the open, just a curl request away.
[1]: Note on some of the screenshots I've preprocessed the data with a lowpass filter st.filter("lowpass", freq=0.1, corners=2) to make it look nicer, while in others I haven't. I'm just an interested person, not doing this on a scientific level. https://imgur.com/a/FjrbWWa
Thanks! I mainly just googled together this stuff in a matter of 1-2 hours. So it was an afternoon project :). But maybe I'll write it into a nice format. It wasn't trivial because the WWW interfaces only show earthquakes but this event was likely only registered by one station and had too low magnitude to be registered by others, and was thus filtered out.
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
> 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 :).
There is a small difference of 3 minutes, but the NSF wording has an "approximately". I guess their priority was to get an initial report out and not precisely determine when it collapsed. I think that a final report on the incident will contain the 12:52 figure instead of the 12:55 one.
Anyways, that's just splitting hairs. Glad that nobody got hurt. This incident is obviously a tragedy.
Do you happen to know of some sources where I can find more API access to data and information like this? I'd love to be able to pull seismic data, weather data, ambient light data (as examples) or any other kind of data from all over the world just for fun.
Any hints on finding seismic data from elsewhere in the world? There was a small event in South America yesterday I'd love to hit with data sciency stuff.
Raspberry Shake (citizen science seismometer network) may be interesting to you. I haven't used it myself, so I'm not sure if it's real time: https://raspberryshake.org/data-center/
Reason 1: because they were afraid of it failing catastrophically just like what happened this morning. One person was on site (director of telescope operations Angel), but imagine what would have happened if a work crew was up in the structure working on cables during such a failure.
Reason 2: They are not going to build a new one. NSF has tried to get rid of AO for a long time now.
I'd like to know more about why "NSF has tried to get rid of AO for a long time now." Anybody knows something interesting and specific? What I was able to find was the Washington Post 2007 article, where it's mentioned that:
"states with major observatories, such as New Mexico and West Virginia, have senators famous for their power over purse strings, some of whom are already gearing up to fight proposed cuts. By contrast, Puerto Rico, a commonwealth of the United States, has no senators. And its representative in the House" "does not have a vote."
and "The cash crunch stems from a "senior review" completed last November at NSF." and
""The ambitions of the astronomy community for new things was far outstripping the capacity of the federal budget to cover them," said Wayne van Citters, NSF's astronomy division director, who organized the independent review"
Well sure, but a hypothetical new structure is also going to require cables, just hopefully a more reliable construction. So why not keep the dish for now, and consider rebuilding the cables in a more modern fashion, and with redundant cables?
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 ago. But they didn't have the funding.
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.
This was basically a whole building suspended into the air. Science or magic? Amazing engineering to be sure (but maybe not built with maintenance and security in mind)
Are there not unmanned solutions to the problem? Drones with flying abrasive chopsaws? Literally strap a Dewalt circular saw onto a big enough drone with the power button taped down? Use a drone to attach a dynamite to the cable? It seems weird to me that the government can figure out how to remotely bomb a town but can't figure out how to remotely do a little snippy snip snip on a cable.
Flying buzzsaws seems unlikely to work, but I don't think snipping the old cables would even be the hard[est] part. Installing new cables would almost certainly require workers to be present on the center platform, and it obviously wasn't safe for anybody to be there.
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.
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.
I assumed that in 2020 we have unmanned solutions to taking something down, and then rebuilding would be done with proper engineering as if it were a new radio telescope but the dish is already built for you.
No robot currently exists that can replace even a tiny fraction of the tasks a 16 year old teenager with a hard-hat and steel toed boots can do at a construction site.
Think of a house of cards. Now think of being required to replace a middle layer without disturbing the cards above it. Also, each card weighs forty tons and, on falling, will kill some or all of the people working on the repair job and take out enough structure to make the whole thing a writeoff anyway.
The thing that was hanging suspended above the dish was weighing 900 tons. I don't know how it could be that heavy (it's probably pretty big), but that sounds too heavy for any helicopter or drone to lift - even if it only had to hold 1/100th of the weight of it while the cable was being replaced.
The answer is that they almost certainly built it with almost nothing hanging in the center, and without the dish below it. Once the basic platform was in place, then they hoisted up all of the components to build out the 900 ton platform (actually, that took years and years as equipment was added to upgrade it).
So, in essence, doing a replacement of all of the cables would need to start by essentially disassembling the thing completely and then rebuilding it.
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 closer inspection, the first event is actually multiple smaller ones, not sure if they are related to the collapse at all. The second event is clearly one discrete thing though. The image was uploaded to twitter at 11:56 UTC, so minutes within the collapse being recorded on the seismograph. You can still see the dust in the air.
Pretty cool that all this data is out there, in the open, just a curl request away.
[0]: https://www.fdsn.org/networks/detail/PR/
[1]: Note on some of the screenshots I've preprocessed the data with a lowpass filter st.filter("lowpass", freq=0.1, corners=2) to make it look nicer, while in others I haven't. I'm just an interested person, not doing this on a scientific level. https://imgur.com/a/FjrbWWa