Arecibo Observatory Collapsed • Hacker News Board

Re: Arecibo Observatory Collapsed

#141

Post by 0xffff2 » Tue, Dec 01, 2020, 5:13 PM UTC

fanf2 wrote: post #55

rurban wrote: post #39

So planetary defense relies solely on a few 1m telescopes. Interesting. Maybe the "Dish" (Australia) also. The two remaining big ones, the chinese and the russian cannot do that. https://en.wikipedia.org/wiki/Asteroid_impact_avoidance The remaining bigs: * https://en.wikipedia.org/wiki/Five-hundred-meter_Aperture_Sp... * https://en.wikipedia.org/wiki/RATAN-600

I am not sure what you mean by “planetary defence”? One of the unusual things about Arecibo was that it could transmit as well as receive (like The Dish / Parkes telescope); that work is mostly done by the NASA deep space network, which uses fairly large steerable telescopes https://en.wikipedia.org/wiki/NASA_Deep_Space_Network

NASA uses "planetary defense" to refer to activities related to detection of dangerous asteroids. The DSN is used for communication with our various satellites and probes outside of Earth orbit. AFAIK, it doesn't play a role in radio astronomy of the kind Arecibo did.

Re: Arecibo Observatory Collapsed

#142

Post by kzrdude » Tue, Dec 01, 2020, 5:21 PM UTC

vidanay wrote: post #138

paulirish wrote: post #115

Earlier quoted context omitted.

And just posted… pictures of the destroyed reflector dish: https://twitter.com/DeborahTiempo/status/1333806230125604867

Wow. At least one of the concrete towers appears to have completely snapped off at the last step from the top.

The uppermost section snapped on two of the towers and the last tower lost the two uppermost sections.

Re: Arecibo Observatory Collapsed

#143

Post by leephillips » Tue, Dec 01, 2020, 5:22 PM UTC

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…

Interesting! You should write this up. Your comment has more content than most Medium articles that I’ve seen.

Re: Arecibo Observatory Collapsed

#144

Post by jonas21 » Tue, Dec 01, 2020, 5:31 PM UTC

skuhn wrote: post #59

ISL wrote: post #40

Earlier quoted context omitted.

The FTE employee-count alone underestimates the impact of national-scale science infrastructure. naic.edu is down right now (I suspect they're busy at the moment), but their data is used by tens to hundreds of institutions, each partially employing faculty, postdocs, and students. For agencies like NSF, the science is sometimes almost secondary. What matters perhaps the most is that qualified and capable students con…

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…

Note that the NSF isn't the only agency funding science in the US. For example, the NIH spends nearly all of its $40 billion annual budget funding scientific research.

However, I think this does speak to your earlier point about politics. It's easier to get people on board with funding "health" (since everyone cares about their own health) than it is for "science"

Re: Arecibo Observatory Collapsed

#145

Post by brabel » Tue, Dec 01, 2020, 5:31 PM UTC

colechristensen wrote: post #98

Frondo wrote: post #79

Earlier quoted context omitted.

I would sooner credit the 35th rule of acquisition ("Peace is good for business") than American foreign policy for the lack of a global conflict.

But then what changed between 1900 and 1945? We had two world wars between those years and nothing but small localized wars never between major powers after? Weapons. We developed weapons that could sanitize the planet, and in the case that someone might challenge our intention to actually use them, we developed weapons that ran the spectrum so that war against us would always seem a major losing proposition. The onl…

Small localised wars??

Did you know that the Vietnam War had the biggest aerial bombardment in history[1], of all wars?

The body count in Vietnam easily exceeded 1 million and may be as high as 4 million[2].

Do you think that's a small, localised conflict?

[1] https://en.wikipedia.org/wiki/List_of_bombing_campaigns_of_t...

[2] https://en.wikipedia.org/wiki/Vietnam_War

Re: Arecibo Observatory Collapsed

#146

Post by dylan604 » Tue, Dec 01, 2020, 5:31 PM UTC

skuhn wrote: post #38

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.

The problem (partly) is that the F-35 program puts money into 307 congressional districts in 45 states [1]. These insanely expensive defense projects are wealth transfer programs that make contractors like Lockheed and their many sub-contractors rich, and also create jobs in these communities. That a fighter plane may or may not come out the other end is only nominally important, the key is to spend the money. The mo…

Then let's build a new Arecibo-esque observatory in each of the 50 states and other territories. We'll combine all of them together to make the VLA look tiny. That'll be 120 employees multiple by the number of locations so we're talking > 6000 employees. Plus, all of that science.

Re: Arecibo Observatory Collapsed

#147

Post by floatrock » Tue, Dec 01, 2020, 5:32 PM UTC

TeMPOraL wrote: post #35

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?

The anecdote I heard was that it was because there was no good way of getting data on the USSR over-the-horizon radars - other than the times where their signals would reflect off the Moon and could be analyzed by the US, given good enough antennas.

A week or two ago when HN was discussing the second cable snapping, someone posted this origins history of silicon valley video: https://youtu.be/ZTC_RxWN_xo?t=2983 (the entire thing is about electronics and radar development from the atomic age through the cold war, interesting to watch whole but the timestamp link is the relevant radio telescope part).

Short story: before our nuke strategy shifted to basically all ICBM's and submarines, the plan was to nuke the soviets with fleets of long range bombers. To get the bombers in, though, you needed to know where the air defense radars were. The U2's were good at flying too stealthily and too high for missiles, but not great... one or two did go down creating some, er, light international incidents. So eventually someone figured out big air defense radars bounce off the moon when the moon is overhead, and suddenly there was a lot of CIA money funding radio telescopes like Arecibo and the Stanford dish.

Re: Arecibo Observatory Collapsed

#148

Post by skuhn » Tue, Dec 01, 2020, 5:35 PM UTC

earhart wrote: post #134

skuhn wrote: post #116

Earlier quoted context omitted.

The wind gently whispers: socialism.

More like a UBI. Or extended social security. Socialism's more about the community owning and managing the means of production, and less about just giving people money. You could make a good case that the F-35 program, with all its bloat and cost overruns and inefficient distribution of funds by congressional district, is typical of a socialist jobs program -- granted, the F-35 also has a layer of capitalist sharehol…

The F-35 program is indeed a lot like socialism. And I think the layer of skim off the top is well represented in centrally planned economies like the Soviet Union. It was taken by well placed government ministers rather than business oligarchs.

My comment was intended to be more tongue-in-cheek. People fear socialism, but capitalism is not the answer to all of the world's problems.

People have basic needs: safety, sustenance, shelter, self-determination. They have higher level needs too, and we aren't living in a post-scarcity society yet, but we have the resources to meet these basic needs for at least 328 million people.

Re: Arecibo Observatory Collapsed

#149

Post by ajford » Tue, Dec 01, 2020, 5:37 PM UTC

z2 wrote: post #100

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…

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 deform the surface. Heck, the reason the dome is so massive is that it holds a secondary and tertiary reflector to convert the focal line (an artifact of the primary reflector being a spheroid instead of a parabola) into a focal point.

Also, the 30-ton platform in FAST is the main limitation preventing FAST from being able to perform planetary radar science. It is too small and cannot support the weight necessary for a radar system of sufficient capacity.