It’s been nearly four years since the Arecibo Telescope collapsed, an event the world got to witness in unprecedented detail thanks to strategically positioned drones. They captured breathtaking video of one of the support cables pulling from its socket as well as the spectacularly destructive results of 900 tons of scientific instruments crashing into the 300-meter primary reflector. But exactly why did those cable sockets fail?

A new report aims to answer that question, and in the process raises some interesting questions of its own. The proximate causes of the collapse have been known for a while, including the most obvious and visible one, the failure of the zinc “spelter sockets” that were cast around the splayed ends of the wire ropes to hold them in place. The new report agrees with this conclusion, at least in part, implicating “zinc creep,” or the tendency for zinc to deform over time under load. Where it appears to differ, though, is with the quality of workmanship on the sockets, finding no issues with the way the individual wires in the failed support cable were manually splayed within the socket before the molten zinc was poured. The report also points out that the collapse probably started when Hurricane Maria swept over Puerto Rico 39 months before the collapse, after which zinc creep in the sockets seemed to accelerate.

But why did the sockets fail? As the report points out, spelter sockets are commonly used to anchor cables that support heavy loads under conditions similar to the tropical climate at Arecibo. After ruling out every other cause, the committee was left with the conclusion that Arecibo itself may have been to blame for the accelerated zinc creep, thanks to electrical currents induced in the cables and sockets when the telescope’s powerful transmitters were used. They call this “long-term, low-current electroplasticity.” Electroplastic effects have been observed since the 1950s, and while far from certain that’s what happened here, the thought is that skin-effect currents induced in the support cables flowed to ground through the zinc sockets, increasing the plasticity of the metal and accelerating the zinc creep that ultimately led to collapse.

Case closed? Hardly. The electroplasticity mechanism for the Arecibo collapse offered by this report is almost a “diagnosis of exclusion” situation. It makes sense, though; since no other spelter sockets have ever failed this way in a century of use, there’s a good chance that the root cause was specific to Arecibo, and since it was once the world’s most powerful radio transmitter, it seems like a red flag that bears further investigation.

Remember that time a giant cylindrical aquarium in a Berlin hotel bar catastrophically failed and left thousands of fish homeless? We sure do, and further recall that at the time, we were very curious about the engineering details of how this structure failed so spectacularly. At the time, we were sure there’d be plenty of follow-up on that score, but life happened and we forgot all about the story. Luckily, a faithful reader named Craig didn’t, and he helpfully ran down a few follow-up articles that came out last year that are worth looking at.

The first is from prosecutors in Berlin with a report offering three possibilities: that the adhesive holding together the acrylic panels of the aquarium failed; that the base of the tank was dented during recent refurbishment; or that the aquarium was refilled too soon after the repairs, leading to the acrylic panels drying out. We’re a little confused by that last one just from an intuitive standpoint, but each of these possibilities seems hand-wavy enough that the report’s executive summary could have been “Meh, Scheiße happens.”

The conclusions reached in the prosecutor’s report come from a forensic analysis conducted by Professor Christian Bonten, who the building owners commissioned to get to the bottom of things. The work began soon after the accident with an on-site analysis of the debris field, followed by laboratory studies of 90 tonnes of recovered shards. They put over 1,100 hours into the effort, examining evidence down to the molecular level via chemical analysis of the polymer chains in the acrylic. Still, the best they could come up with was that the collapse was “sudden and unexpected,” a sentiment the fish would no doubt agree with, and that there was no way anyone could have predicted it. That’s a bit frightening; while the world isn’t exactly littered with giant aquaria like this, they aren’t unknown either, and the idea that any of these structures could fail without warning is chilling. Especially if you’re a fish.

The Covid pandemic lockdowns were difficult for a lot of people, but they did provide a (hopefully) unique opportunity to observe just how much the activity of 8 billion people has on our planet. We recall a ton of non-intuitive results such as decreased background noise in seismic observations, pollution maps that suddenly cleared up, and even changes in the behavior of wildlife. But one impact we really didn’t see coming during “The Anthropause” was a decrease in the surface temperature on the Moon. Researchers looked at data from six sites on the near side of the Moon during lunar nights from 2017 to 2023, and found a subtle but unmistakable dip in temperatures during April and May of 2020, the peak of the lockdowns. They explain that the decrease was due to lower longwave IR emissions from the Earth’s surface thanks to decreased greenhouse gas emissions during the period, which we find pretty fascinating.

One of the benefits of writing for Hackaday is the crazy random rabbit holes that we get to go down, especially when we’re doing research for an article. Such a thing happened this week with a random thought that popped up while reading something about the International Space Station: What would they do if someone died up there? Thankfully, we’ve had precious few space fatalities in the last 70 years, and those have mostly been restricted to launch and reentry, and hence have been — ahem — extremely energetic deaths.

But with two space stations in orbit hosting long-duration crews in an inhospitable environment, eventually the law of averages is going to catch up to us and someone is just going to die up there. Then what? We found an article from 2021 that attempts to answer this with the help of the indispensable Commander Chris Hadfield, who offers insights that suggest his tours on the ISS have given him plenty of time to mull it over. But the real treat in the article is the idea of adapting an idea known as “promession,” which would involve freezing a corpse in liquid nitrogen and then rapidly vibrating it to break it into tiny bits, suitable for rapid composting. The on-orbit version would skip the liquid nitrogen and use the cold of space, with a robotic arm used to vibrate the astronautsicle and pulverize him or her. The article takes some weird turns — Martian cannibals? — which is understandable given that at the time it was written, NASA didn’t really have a plan for what to do with dead astronauts. But fear not, because they seem to be working on it now.

And finally, we stumbled across a video looking into the mysterious inner workings of vintage elevator controls that we found strangely compelling. The elevator in question is a Schindler lift with an odd design; rather than sliding doors on both the car and the landings, this one just has the doors on the landings, and those are swing-type doors. It’s fascinating to watch the doors glide by as the elevator goes up and down the cleanest elevator shaft we’ve ever seen. Even tidier is the hoist room, which is filled with the snappiest relays and coolest old controls you’ll ever see.