Drone Footage of Arecibo Observatory Collapse • Hacker News Board

Re: Drone Footage of Arecibo Observatory Collapse

#21

Post by ljp_206 » Thu, Dec 03, 2020, 5:55 PM UTC

blhack wrote: post #17

Is there any chance at all that this gets rebuilt? Is anybody even putting the costs requirements together to do it, or is this just a total loss? This is so unbelievably sad to see. It reminds me of seeing Notre Dame burning last year.

IIRC it was a total loss by the time the first cable broke. With the collapse, at least the structure is now safe to approach and begin scrapping/full deconstruction.

Re: Drone Footage of Arecibo Observatory Collapse

#22

Post by madengr » Thu, Dec 03, 2020, 5:57 PM UTC

bob1029 wrote: post #12

lgrebe wrote: post #6

Why were they filming? As in why was the drone in place and looking at a close-up of the cable?

This is quite the coincidence. The drone operator seemed prepared for exactly what was coming.

There's that saying about the "flap of a butterfly's" wings initiating a hurricane. In this case it's the prop wash from a drone.

Re: Drone Footage of Arecibo Observatory Collapse

#23

Post by madengr » Thu, Dec 03, 2020, 5:59 PM UTC

woeirua wrote: post #11

Is the loss of Arecibo a big blow to the scientific community? I was of the impression that Arecibo was long past it's heyday and in general that large arrays of smaller receivers were now considered superior.

China has one that's bigger.

Re: Drone Footage of Arecibo Observatory Collapse

#24

Post by jeffbee » Thu, Dec 03, 2020, 6:03 PM UTC

NikolaeVarius wrote: post #18

I wonder whats going on with the cable when it fails. It seems to be snapping/frays at first, but then it seems like it was pulled out of its base

Why not both? At first a few strands of one cable are snapping. Then the remaining strands break altogether. Then the remaining cables also break. Finally, one of the towers fails because it's designed to take a vertical load and suddenly it is supporting a net horizontal load.

Re: Drone Footage of Arecibo Observatory Collapse

#25

Post by sp332 » Thu, Dec 03, 2020, 6:03 PM UTC

blhack wrote: post #17

Is there any chance at all that this gets rebuilt? Is anybody even putting the costs requirements together to do it, or is this just a total loss? This is so unbelievably sad to see. It reminds me of seeing Notre Dame burning last year.

They barely had funding to do maintenance. There's no money to build a whole new one. The NSF is under contract to return the site to its original natural state. (I can't find a recent source for this but it's mentioned in https://www.scientificamerican.com/article/search-for-alien-... )

Re: Drone Footage of Arecibo Observatory Collapse

#26

Post by Jaruzel » Thu, Dec 03, 2020, 6:03 PM UTC

sasvari wrote: post #3

direct link to the video: http://players.brightcove.net/679256133001/EkLWnGuil_default...

Copy of video on YouTube: https://www.youtube.com/watch?v=RU6YYTp72To

Re: Drone Footage of Arecibo Observatory Collapse

#27

Post by briancp » Thu, Dec 03, 2020, 6:03 PM UTC

Posted this in another thread, but there’s some neat photos from the 60s of the telescope under construction here: https://www.naic.edu/history_gal/historicgal.html

Beyond the scientific value, it is (was) just a neat feat of engineering getting this built in the middle of the jungle.

Re: Drone Footage of Arecibo Observatory Collapse

#28

Post by lambda_obrien » Thu, Dec 03, 2020, 6:04 PM UTC

_verandaguy wrote: post #16

spenczar5 wrote: post #15

Earlier quoted context omitted.

I work at UW astronomy. It’s mostly symbolic. The main capability loss is that Arecibo was able to transmit, which is unique at its size. As an example, that was useful to rescue the ISEE-3 explorer when it passed through a comet trail in the 1980s. Only Arecibo was powerful enough to blast a radio message through the comet trail. (PDF reference: https://ipnpr.jpl.nasa.gov/progress_report/42-84/84T.PDF ) Arecibo was…

Asking as a non-astronomer: my understanding is that other telescopes in this class are synthetic/multiple aperture, and not single-aperture like Arecibo (with a small number of exceptions, like FAST). Is there any science you can do on extremely-large single-aperture telescopes that you can't do on comparable synthetic/multiple aperture telescopes?

Arecibo was initially built to excite plasma balls in the atmosphere to study them, and was also used for other transmitter uses that required a super powerful transmitter, initially designed for that plasma use.

Re: Drone Footage of Arecibo Observatory Collapse

#29

Post by sp332 » Thu, Dec 03, 2020, 6:06 PM UTC

NikolaeVarius wrote: post #18

I wonder whats going on with the cable when it fails. It seems to be snapping/frays at first, but then it seems like it was pulled out of its base

The anchor is made by unraveling the strands, covering them in concrete, and wedging the solid block in a cone-shaped opening so it can't pull out. One of the other cables also failed at its anchor, which is really not supposed to happen, so maybe something similar happened here. One or two strands managed to pull out of the block individually, leaving enough room for the rest to pull out in one piece?

Re: Drone Footage of Arecibo Observatory Collapse

#30

Post by ilamont » Thu, Dec 03, 2020, 6:06 PM UTC

The instrument platform was listed at 900 tons. The maximum takeoff weight of a Boeing 787 is just over 500,000 pounds, or 250 tons ... is it fair to say the instrument platform was the equivalent of three fully loaded 787s, plus two M1A1 tanks piled on for good measure? That's a lot of weight for those cables to support.