A new drone!

So this post is actually several months late, for reasons I'll explain shortly. You see, back in May I got a new drone: the DJI Avata. I got it right before taking a trip to visit my family in California, and was excited to start sharing footage from it. One small problem: the video editor I use (KDEnlive) crashed every time I imported a clip into it. Not clips from my Mini 3 Pro, or GoPro 9, mind you, only the Avata.

I considered trying a different editor – maybe learning how to use Blender for video editing – but I'm busy, and lazy, and didn't get around to it. Fortunately, when I upgraded my computer from Debian 11 to 12 last month, something in amongst all the upgrades seems to have fixed the problem, allowing me to continue using what I know to make videos with Avata footage. Huzzah! And now that I can, have not just one, but two new videos!

Before that, though, a quick digression on types of drones, of which there are essentially two nowadays. They don't exactly have defined names (and all categories are blurry to some extent), but I've seen the name “flying cameras” to describe drones like my first one, the Mini 3 Pro. These are drones which are meant (generally speaking) for eye-in-the-sky photos or smooth cinematic video clips, up in air away from obstacles, since they're generally pretty delicate and a collision with almost anything will knock them out of the sky due to their unprotected propellers.

The other type is first-person view drones (or FPV). FPV drones project their camera feed directly on a headset instead of a controller, giving a pilot a more immersive experience which makes it somewhat easier to judge a drone's position and distance from obstacles. FPV drones generally focus on video rather than photos, and often from much closer to objects than the other type of drone. They're generally pretty hearty and damage resistant, and some (like the Avata) have propeller guards, allowing them to fly in close proximity to people and even potentially bounce off obstacles without getting knocked out of the air. (Though there are also ones without propeller guards.)

Since the Avata is so tough (as plenty of reviews on YouTube will attest), I wasn't too worried about letting my family fly it. There were some crashes, as expected (the Avata is good at getting you to take risks while flying it), and I thought splicing some of the resulting footage together could make for an amusing video. In this video, all the footage is from when my two brothers were flying (but while the crashing is amusing, lest you think they're terrible pilots I also included some non-crash footage to balance it out).

And to reassure that my drone is, indeed, still fine after those crashes, I have a second video. The footage for this was taken just a few weeks ago after discovering I could use it in my editor. This video was taken at Waiale Falls on the Wailuku river, not too far from where I live. The river's pretty low right now, so I thought I'd try flying up and down over the falls.

I wasn't originally planning to make a video out of this footage (hence why it's two clips put together rather than one long one), as my original motivation for taking it was trying out Gyroflow. Gyroflow is a program which can take GPS data embedded in a video file to stabilize it after it was taken, and a lot of people swear by it for video stabilization. It requires turning off any electronic image stabilization (such as I had on in the first video), and running the footage through Gyroflow after taking it, but I was impressed enough with the results that I decided to turn a few clips into the video above, and I can see why people speak so highly of it.

Anyway, I hope to be able to make and share some new types of videos with my Avata in future! One drawback it does have is that it's seriously loud. That's just par for the course for FPV drones since they need a lot of power, but it's not helped by the fact that it generally gets better footage when flown closer to the ground rather than up in the sky like my Mini 3 Pro. I dislike flying it around people, but it's a big island, so I'm sure I can find some nice secluded places to go flying.

And finally, while I know I've picked up two drones in less than a year since I started flying, I don't have plans to amass a large fleet or anything. I've got a representative of each of the two main categories of drone now, and while it's possible I might upgrade to newer models in future, they're both quite capable enough already that I don't see a big need to do so for a while. A hui hou!

Fun with drones in the California countryside

Back in May I took a short trip over Memorial Day weekend to visit family back in California. This was the first time I'd been back since I starting drone flying last July, so I was looking forward to seeing some familiar places from the air. My brother Joel also has a drone (in fact he started flying before I did), so together with my other brother Jonathan we had some fun going drone flying together. After a session out in the countryside, as we were getting ready to come home I had the idea of following our car from the air (while driving slowly, on a deserted country road, with multiple people for extra situational awareness).

I've never operated from a moving vehicle before, and it was a fun experience practicing my cinematic moves trying to track the car while also riding in it. The full video was a bit too long to be interesting, but I extracted a few nice shots and put them together into the shorter version below. I'm especially proud of the bit near the end where, as we went under I-505, I managed to transition on the fly (literally!) from following mostly behind the car to instead tracking it from straight above. (I even left the ugly jerky animation bits in there which I've cut out from the rest of the video, just to show how it worked.)

Anyway, just a calm video of a relaxing drive through the countryside. (I've left out the parts where I almost ran into power lines…twice. It was fine.) And thanks to some recent system updates, I might have something new in a similar vein to show off pretty soon. A hui hou!

Rereading Sherlock Holmes

Recently I reread the entire series of Arthur Conan Doyle's Sherlock Holmes stories, after I discovered they're all freely available online. My father read them to us as bedtime stories when I was growing up, and I still remembered various bits and pieces, but I'd forgotten enough in the meantime to enjoy them again.

Coming back to them with the experience of the intervening years has also been interesting in various ways. The best example I can think of comes from the short story “The Boscombe Valley Mystery,” a murder mystery where the murdered man's dying words, according to his son who was the only witness, were something nonsensical about “a rat.” Elsewhere in the story it was mentioned that the victim made his money in Australia, and since I read the story over a few days I was standing there brushing my teeth one night when I suddenly thought, “Hang on, it's not going to turn out to be a reference to Ballarat, is it?”

Ballarat is a town in Victoria, a few hours west of Melbourne up in slightly rolling hills, and was a major location in the Victorian gold rush which began in 1851 and lasted around twenty years. I visited it twice while I was living in Melbourne, once as part of a graduate student workshop prior to the 2018 Astronomical Society of Australia meeting, and once with my family when they visited in 2019. Both times we visited a tourist attraction called Sovereign Hill, which has a period-accurate gold mining town with various sights and activities. I thought I'd written about it before, but apparently not; for whatever reason I didn't take many photos either time I was there there. This is one of the better ones, showing a panoramic view of the center of the area.

Sovereign Hill, from up on a mining-derrick-turned-viewing-platform.

It's a more interesting attraction than my lack of photos might make it seem; there are lots of buildings with things like authentic black-smithing exhibits, a tour underground through an old mine shaft, a sort of 19th-century offshoot (precursor?) of bowling that you can still play, and perhaps my personal favorite, a demonstration by a metallurgist where the presenter melted a bit of gold and poured it into an ingot while talking though the process. (The indoor lighting and brilliance of the molten gold combined to render my photo attempts not worth sharing, unfortunately, but it was pretty neat to watch.)

Anyway, I've got a bit off topic; I thought of Ballarat in conjunction with the story, and wouldn't you know it, it did turn out be a reference to the town (though I won't spoil the ending). Overall I found the stories to be as engaging as they were growing up, even apart from a few cases of Science Marches On in the century-plus in between. (One major case is in the plot of “The Adventure of the Speckled Band,” [regarded by fans and Doyle himself as one of the best stories, if not the best], which involves a snake; what it supposedly does makes no sense at all from the perspective of snake biology, though it undeniably remains a good story outside that.) It's nice to discover the stories are free to all to read, and if you haven't read them, I can recommend them; it's easy to see why they've enjoyed continuous popularity since they were first penned. A hui hou!

Drones, geology, and the tropical sun: a case study

On the slopes of Maunakea, a short distance east of the Visitor Information Station and Hale Pōhaku, a small pit crater (sometimes evocatively called “Bottomless Pit”) can be seen on satellite imagery.

I've circled it in this wider view of the area, it's not very big.

I thought for sure I'd mentioned it before on this blog, but a search failed to turn up anything. I find myself surprised at this, because I've been aware of this crater for over a decade now, and I've wondered how deep it goes for nearly as long.

You see, this crater is a bit unusual. There are many puʻu, or cinder cones, on Maunakea, and plenty of eruptive vents on Mauna Loa and Kīlauea. But from the ones I've seen up close, such eruptive vents are always filled in pretty close to the surface with hardened lava or choked with tumbled stone. This pit crater is unusual because, alone of all the craters I've seen on this island in Google Maps (and I've spent many hours looking), it has a dark hole at its center.

A closer view of the crater, with the hole clearly visible.

My first encounter with this crater actually came all the way back in 2012, which is how I know I must've discovered it within a few years of moving to the island. I don't remember the exact date, other than that it was on (or very close to) the night of a full Moon, and (for a few reasons) probably sometime during the summer.

I was working at the Visitor Information Station in 2012, and sometimes I'd have multi-day shifts, where I'd stay overnight in one of the rooms at Hale Pōhaku. I think I must've recently discovered the crater at the time, as I was very interested in hiking out to see it. I didn't have a car at the time, so while I could ride up to the VIS for work, I didn't have time during the day in which to visit the crater. (This recent discovery/fixation may help explain what follows.)

I'd just finished a day of work and gotten back to my room at around 11 PM, when I was struck with a crazy idea: why not hike the roughly half-mile distance out to see the crater? It was a full Moon, and there was plenty of light. (There were some light clouds steadily blowing west overhead, but not enough to seriously dim the moonlight.)  To my early 20s brain this made perfect sense; I was in pretty good shape, and could still miss an hour of sleep without feeling it too harshly the next day, so without telling anyone I was going for a nocturnal jaunt I grabbed my trusty headlamp and set off to the east.

In retrospect of course, going for a high-altitude hike at night to a geologic feature of unknown depth without telling anyone has Not A Good Idea written all over it. As mentioned, I think this must've been during the summer, as I remember the night being relatively mild, but it still wouldn't have been very fun to have been caught out overnight if I'd, say, sprained an ankle. And one thing I didn't know before setting out is that the ground between Hale Pōhaku and the crater is some of the best terrain I've ever seen for twisting an ankle, being mostly loose soil with fist-sized rocks that turn over at the touch of a feather (or at least a hiking boot).

Still, after half an hour or so of trudging over hill and dale (there's a ridge between Hale Pōhaku and the crater which isn't apparent on the map), I made it to my target, approaching from uphill (the northern side). As I crested the rim of the crater, I had an impression of it lying sprawled before and below me, and in its center, a yawning maw of inky blackness large enough to swallow a person. The full Moon overhead, the patchy clouds, the just-completed trek through silent shadowy solitary surroundings, and the anticipation I had for the event all combined to engender a feeling of solemn awe and make it a momentous, even portentous event.

I felt this feeling of awe for perhaps a full second, maybe even two, when a bird suddenly exploded out from where it was nesting not far from where I stood in a loud whirring of wings and squawk of alarm, giving me the fright of my life and nearly startling me over the edge of the crater as I reflexively jerked around.

I managed to retain my balance and not fall into the crater (thankfully, as will become apparent). I think, after recovering from the fright that hapless avian denizen gave me, I tried to take a few photos, but the light wasn't enough for them to come out. To make a long story short, after some more minutes admiring the awe-inspiring nighttime scene I headed back to bed with no one the wiser about my ill-advised midnight perambulation. And that was actually the last time I visited the crater for a full decade.

But even apart from it, all those years, I continued to wonder: just how deep did that pit go, which had left such an indelible impression upon my younger self? In those intervening years, I moved to Australia, got a PhD, and moved back to the island, and in between something new entered the pictures: drones.

While consumer-facing drones have been around since well before I moved to Australia in 2017, early models were cruder and less functional than the ones available today, and I wasn't really aware of their slowly improving capabilities. My vague impression was that they were mildly interesting toys, but not much more. (I also didn't exactly have the disposable income to buy one at the time, so I wasn't paying much attention.) Regardless of how accurate my assessment was at the time, it's true that drones have only continued to improve since, and in mid-2020, while stuck at home in lockdown in Melbourne, I started coming across videos on YouTube that opened my eyes to just what modern drones could do.

Enter another piece of information: Hawaii's location in the tropics. This fact means that, twice a year as the Earth progresses along its orbit, the Sun passes directly overhead. I don't remember when I first put two and two together, but at some point I had the thought that, at just the right time, the Sun would be directly overhead, casting its rays down the mouth of the pit…and that if I were to, say, be flying a drone over it at that time I could get an idea of just how deep the rabbit hole pit crater went.

Lāhaina noon (the modern name for when the Sun passes overhead) happens in May and July for Hawaiʻi island. (It happened last week, July 24th, in Hilo.) Last year I was excited to get my Mini 3 Pro in June, in time to catch the Sun in July. I even hiked out to the crater for the first time in a decade the week before Lāhaina noon to scope the area out, only to fall sick that week and be unable to head up Maunakea on the day itself. Still, I wasn't discouraged, and philosophically reasoned that a year's experience with drone flying would help me next time around. This year the May Lāhaina noon happened in the middle of the week, but the July one happened over the weekend of the 22nd/23rd, so I possessed my soul in patience and bided my time. I did get some pictures, though:

The crater July 2022, with the pit in the middle. A bit less spooky under the summer Sun.

This past Saturday, July 22nd, my chance had finally come: I headed up Maunakea with my Mini 3 Pro (and a friend), hiked out along a trail downhill from the crater, and as the Sun reached the zenith, I sent my drone skimming through the air towards the pit.

The crater July 2023, from the air. The hole's a bit bigger than a person, for scale.

And after a decade of wondering about this particularly intriguing geologic formation, I finally had my first glimpse at an answer regarding its depth! Everything, to my surprise, worked out perfectly: the Sun blazed away overhead, its light illuminating the pit, and to my surprise (and delight), it turned out to be significantly deeper than I'd been expecting.

Behold, the pit crater's floor, clearly visible.

A decade of wondering, years of imagining how this moment would go, and I can still hardly believe it went off without a hitch: I was able to clearly see and photograph the floor of the pit. A still photo doesn't show the parallax I saw while flying over it, but from that I would estimate that the bottom of that pit has to be on the order of 10 meters (~30 feet) down, or perhaps more. I took some videos of the effect, and I hope to make a slightly more rigorous estimate before too long, but I wanted to share this photo soon after fulfilling a multi-year dream of mine. (Yes, some people's dreams are inspiring stories of overcoming hardship or taking years to achieve something significant; mine pretty much boils down to, “I wonder how deep this hole goes?”)

It also deepens (pun not intended) the mystery of the hole's origin. There are plenty of cinder cones on Maunakea, especially around this part of the mountain, which are created from explosive eruptive events (which pulverize rock into cinder), but this isn't a typical cinder cone. Looking at satellite photos, the area nearby seems to show signs of a lava flow, and I've read that some of the last eruptions on Maunakea happened around this general area. Perhaps this particular vent was erupting more fluid lava rather than explosive cinders (which tend to fall back and fill in the vent)? That might explain the strangely smooth-looking floor (rather than a jumble of rocks as might be expected): maybe magma, after erupting, drained back in and we're seeing a frozen lava lake from the last lava to emerge from this vent? The area in the crater seems a bit sharp and jagged to have been erupting pāhoehoe, so perhaps it was ʻaʻā, or perhaps I'm barking up the wrong tree entirely. I'm not a geologist and I have no firm explanation for this unusual feature, I just know that of the many eruptive vents and cones I've seen around the island I don't know of another one like it.

A question answered, more questions raised; so it goes in science, and perhaps it's fitting that the pit retains some of its mystery even after being illuminated by the tropical sun. I've got some thoughts on how I might better estimate the depth of that floor, so look forward to seeing something about that when I find time and motivation to work it out some more. In the meantime, this is getting long so I'll leave it here. A hui hou!

Browsing the bonsai

This past Saturday I went down to the Wailoa center to see a bonsai exhibition which I heard about from a friend (and whom I met there to see it with). It proved a rather eye-opening experience. My impression of bonsai, prior to this, was that it always involved conifers or other evergreen trees, but this exhibition included plenty of bonsai made with broad-leafed plants, including some that I found very creative. For instance, here's a three-year-old bonsai made from an oregano bush:

Having grown oregano in my Farmstand I was very interested in this one, since it seems to be a slightly different variety with smaller leaves, and perhaps more inclined to grow into a woody herb. Another surprise was this bonsai citrus tree, complete with (quite a lot of!) fruit:

This one definitely had me thinking about what other fruit trees might be able to be cultivated indoors as bonsai. When I originally got my Farmstand I had thought a bit about the possibility of growing an indoor fruit tree or two, but had given up the idea on the basis that it would probably require an inconveniently-large pot, and that most fruit trees grow larger than the average room height. But these bonsai trees grow out of what I would cordially characterize as absurdly small pots, and bonsai is all about keeping trees artificially small, so perhaps it's not as impractical as I had assumed. I might need to look into this some more.

Of course, there were plenty of more traditional bonsai there too, including a lot of evergreens. I didn't take too many photos of those (though there were many pleasing and impressive ones), but this larger-than-average twenty-year-old black pine stuck out to me:

And finally, even older than that was this Green Island banyan bonsai, at a venerable twenty-five years old:

I'd show a rather beautiful bougainvillea bonsai in flower, but unfortunately my only photo of it came out blurry. All in all the exhibition only took about three quarters of an hour to see, but it was a fun experience all the same, and definitely opened my eyes to what can be done with bonsai. I don't know that it'll become a new hobby or anything, but I can appreciate it more now (though I wish there were some explanation somewhere of what all the many style names mean). I think it's a yearly thing, so I'll have to see if I can get wind of it again next year and see it again. A hui hou!

Happy Tau Day 2023!

As the title says, Tau Day (6/28) is once again upon us, though I forgot about it until my phone reminded me this morning. Tau, if you don't know or have forgotten, is simply the irrational, transcendental ratio of a circle's circumference, C, to its radius, r, or twice the value of pi:

\[\tau=\frac{C}{r}=2\pi=6.283185\dots\]

As detailed in The Tau Manifesto, there are a huge number of reasons that using tau makes so much more sense than using pi. Using pi instead of tau for angular measure is like measuring time on Earth in six-month periods rather than years; both ignore a natural and convenient measure of cyclicity. (You can read the original parable where this is explained in much better detail here.)

This year's State of the Tau continues to collect various sightings or milestones for tau over the past \(e^{i\tau}\cdot365\) days. One thing that stood out to me was that tau has been added as a constant to Java, which is up there in the top three most popular languages last I checked. (It's been in Python, the currently-most-popular language, for several years now.) Slowly but surely, it seems like people are catching on to the fact that math (trigonometry in particular) can be so much easier and more intuitive with a little change in units. Let's hope for a good year to come for tau! A hui hou!

Some new projects, while recuperating

It's been longer than I'd like since last posting here, due to a one-two punch combo: spending a week in California visiting my family over Memorial Day, and then just as I was settling back into a routine upon my return I came down with something that knocked me out for a week. I'm over it now, thankfully; while it wasn't particularly virulent it was tenacious, and just kept hanging on several days after I expected it to clear up.

Although I wasn't feeling particularly creative while ill, I found such creativity as I had focused on some hobbies I hadn't done much with in a while. I turned my hand to wood-burning again, for really only the second time since I tried it soon after moving back to Hawaii while my things were in transit. I had a piece of wood that I'd picked up last year and never done anything with, so I was able to use it for something that'd been on my mind for a while, ever since Gemini Observatory got a new logo last year. The new logo uses just a few shades of orange/brown, making it fairly simple to mimic with wood-burning. At least, that's what I thought, and it did sort-of work out that way in the end, it just took some trial-and-error to figure out which of the various interchangeable tips that came with my wood-burning set could produce what level of darkening. Anyway, here's the finished result:

The logo is intended to represent the two telescopes of Gemini (north and south), hence the negative space line down the middle (and not, as some joked, representing a serious structural flaw in the telescopes!). There's basically just three different levels of orange in the original logo, so the stars should all be the same lightest shade as seen in the telescopes, but such are the pitfalls of experimenting on your canvas. I did learn some interesting stuff about wood-burning from this project, though, so it was a good learning experience. Principally, the fact that it's difficult to get a solid gradient; you can approximate it with a hatched pattern (and I think I did a decent job of that), but there can be differences in the wood grain itself which make it burn faster or slower at different point. (There's a wavy dark mostly-horizontal line in the medium-dark section of the dome on the right, just below the windows, where a line in the wood burned so fast that it got dark no matter how quickly I moved the tip over it.)

Anyway, it was a fun little project, and I'd like to get better at wood-burning, maybe combine it with painting or something in the future. That's something I haven't really gotten back to other than a few abortive attempts at pictures, but instead, this week I found motivation to get back into crochet; and not only that, but to finish a project started and abandoned all the way back in 2017, when I moved to Australia:

Yes, I had a crochet lei in progress that I ended up leaving behind with the rest of my crochet equipment and some other things with some friends while I was away. What I hadn't anticipated was missing crochet enough to pick up some more hooks and yarn in Australia, leading to something of a duplication of effort; but this is the first time I've gone back and looked at what I left behind here. I found this in-progress lei, and since it was already started it was easy to get back into the swing of things and finish it. The center “backbone” (as it were) was done, and maybe 15% of the flowers; I wasn't able to successfully reverse-engineer the stitch sequence I was using back then, but I found one close enough to mimic it. (Though you might be able to work out the original section in the photo above if you squint.)

It's been good to get back to doing something with my hands, and it'll be nice to have something to do in meetings again. We'll see where things go. I was recently given a big collection of knitting needles as well, and I wouldn't mind trying my hand at more knitting in the future. And now that I'm back to mostly-healthy I might have some other projects to share soon – I had a great time flying drones with my brothers in California and have some footage that's begging for editing. But for now, I need to get some sleep, so I'll leave it here. A hui hou!

Fake edit: I realize, looking back at my posts from around the end of 2021, that I don't think I ever mentioned my first foray into wood-burning. A friend at Swinburne had suggested I might find it interesting, so after I first moved into my current place in November 2021 (and while the majority of my hobby materials were in transit) I picked up a little wood-burning kit at Wal-mart for something like $12. It's essentially a soldering iron and some interchangeable tips, nothing too fancy, but I find there's a surprising amount of nuance that can be achieved. Anyway, I picked up a cheap piece of wood along with it and started doodling, ending up with the scene below:

This one, I think, shows the strengths of wood-burning off better; it's very good at creating a sense of natural depth and subtle nuance, rather than my attempts at solid gradients above. I didn't have much of a plan when starting this piece (and it probably shows), intending it mostly as a scratch pad for experimentation, but everything I put down kept working so well that it ended up being a picture with very little I wasn't at least satisfied with. Anyway, that's the extent of my wood-burning experience to date, but as mentioned I'd like to practice more with it in future. For my second project, the one above, I experimented with scratching the outlines of the areas into the wood first, allowing me to invisibly sketch a picture to fill later; that worked pretty well, I think, so I'll be interested to see where that might lead.

Going nuts

Another lap around the Sun, one year finished, another begun…that's right, it's birthday time again. A respectable thirty-four this year. One more and I'll be eligible to be president!

Back in April last year I did a fun little Venn diagram on thing which we call berries, things which are botanically berries, and the overlap between them. Recently it was pointed out to me that nuts have a similar situation, so I figured I'd give them the same treatment and see how they compared.

Compared to the berry version, I had to make the top circle a bit larger to hold all the things I found with “nut” in the name at this Wikipedia page. Sometimes the line on what we call a nut is a bit fuzzy; I did include macadamia nuts, even though I've certainly heard them called simply “macadamias” on occasion, because to me the “nut” feels like an important part of the name. Feel free to disagree in the comments, though. That self-imposed restriction that “nut” appear (significantly) in the name means that a lot of things commonly thought of as nuts are absent; pecans, almonds, pistachios, and cashews, for instance, all don't appear. That's because they are not biologically nuts, and we don't tend to include “nut” in their names, so they don't actually fall into any category listed here. (Adding a “generally considered a nut” circle might be interesting, I suppose, but even fuzzier; considered by whom?)

When I did the berry version, my takeaway was that the various groupings were mostly balanced; in fact, the union of the two was the largest group, indicating that things called berries generally mapped to the botanical definition fairly well. Here, it looks like it's instead skewed towards things which are called nuts, but aren't nuts botanically. I also hadn't even heard of several of the nuts in the middle or bottom categories (they tend to come from Africa or Australia/Oceania).

Anyway, that's all for this post. I'm reminded that the original berry version came about due to time freed up from paper-writing last year, and that I still haven't written anything about my thesis…I'll get to it at some point, I really will! I do have some rough outlines for posts milling about in my head. But for now, a hui hou!

Tolkien-inspired astronomical poetry

For journal club at Gemini today, we had a presentation of a recent paper about the discovery of a second ring around Quaoar [KWA-oh-ar], a minor planet in the outer Solar System which was already known to host one. In an email reminder this morning the host jokingly mentioned something to the effect of the two rings possibly being an adventure for Tolkien fans, which sparked the phrase “two rings for faint Quaoar, up in the sky” in my head. I wrote out the first few lines of Tolkien's famous poem with some rewording and sent it back for some office humor, and having thought over it some more today, here's what I ultimately came up with:

Two rings for faint Quaoar, up in the sky,
Seven for old Saturn, formed of ice and stone,
Nine for Uranus, dark to the eye,
One for Haumea, circling far alone
In the Solar System, where ring systems fly.
One Thing to rule them all, One Thing to guide them,
One Thing to bring them all, and into ringlets wind them
In the Solar System, where ring systems fly.

A bit of doggerel, but I had fun coming up with it. I haven't matched syllable numbers perfectly, but the scansion and timings should all still work.

(The One Thing is gravity, in this case. A hui hou!)

Why excavate at Tall el-Hammam?

After my first post on the subject of excavating Tall el-Hammam, the question of “why” might reasonably arise. To which there are (at least) two answers, a general and a specific one. The general answer might be to reply with, “Why do any sort of pure research with no immediate practical application?” I find archaeology interesting (if a little too dirty and outdoorsy to make a career out of), there's so much we don't know about the past, and it's an incredibly exciting feeling to be the first person to spot the beginning of something odd poking out of the dirt. (Which happened to me a few times this trip.)

The specific answer is that if there's a better candidate for the city of Sodom out there, we haven't found it yet. That's not to say the site was only Sodom; there were several multiple distinct occupation phases, from the Chalcolithic to the Roman period, which were separated enough in time that they probably had different names. (For instance, it may have been [part of] the city of Livias during the Roman period.) We've yet to find a sign with any city name (or any kind of written record – disappointing, but by far the most likely outcome for an excavation), so the identification of the site as Sodom comes down to a few factors: the right place, the right time, the right (relative) size, and (as dramatically revealed over the course of the latest excavation) the right kind of destruction event. I'll tackle these in order, but there's a fair bit to go over.

Tall el-Hammam (from the bus, excuse the reflections–it's difficult to photograph due to its humongous size. This is actually just the upper tall, there's a large, flat, mostly round lower tall off to the left.

A lot of the information here comes from memory of various talks and other interactions with Dr. Steven Collins, the dig director and the person who first (in modern times) identified the site as Sodom. He was struck by the fact that most modern identifications of sites for Sodom and Gomorrah where in the wrong place and the wrong time – south of the Dead Sea (or “sunk beneath its waves”), and of sites that were abandoned centuries before the Cities of the Plain (Sodom, Gomorrah, Admah, and Zeboiim) described in Genesis were destroyed.

Tackling first the question of location: based on the reported geography in Genesis, the Cities of the Plain cannot have been south of the Dead Sea; they must have been to its north. (Collins like to point out with amusement that there's actually more information about the geographic location of Sodom than any other city in the Bible, if you know what to look for.) As a first clue, Abraham is reported to be able to look out to where they were destroyed from his camp between Bethel and Ai, which were a bit north of Jerusalem and northwest of the Dead Sea. This immediately removes the south of the Dead Sea from consideration, since you can't see there from that location. And for the 19th and 20th century scholars who basically shrugged their shoulders and decided the cities had sunk beneath its waves, modern science shows that the Dead Sea has only shrunk since the time of Abraham, so there can't be any “lost cities” conveniently hidden away down there.

The “plain” in Cities of the Plain (“kikkar”) is actually not primarily a geographical term, but has as its root idea the concept of “roundness;” it's also used of coins, and flat round bread (think pita in the Middle East, tortillas in the Americas). The term used translates to something like “the kikkar of the Jordan,” and looking at a map it's not hard to see how the Jordan flood plain just north of the Dead Sea makes a round-ish plain. (Genesis also describes the kikkar as “well watered [before its destruction]…like the land of Egypt,” which would fit the flood plain nature of the area – even today it's where most of Jordan's agriculture happens.)  Abraham could easily see the entire plain from where he was camping, but definitely couldn't see to the south of the Dead Sea. So the Cities of the Plain must be located somewhere in that area.

The Jordan flood plain north of the Dead Sea, with Tall el-Hammam circled, just south of the (modern) Kafrein reservoir, which dams the waters of the wadi that would've provided water to the city.

Now, the question of time: when were the cities destroyed? The general scholarly consensus is that Abraham and the other patriarchs lived in the Middle Bronze age; specifically, around 1900–1800 BC. This helps rule out other sites that have been put forward for Sodom and Gomorrah, like Bab-edh-Dhra and Numeira, which were abandoned already in the Early Bronze age, hundreds of years too early. (Also, they're south of the Dead Sea.)

So Collins went looking for cities in the Jordan flood plain, present at least in the Middle Bronze age, and found some, with Tall el-Hammam being by far the largest. And not merely in its local neighborhood, but as the excavation has proceeded, it's been discovered to be the largest site in the southern Levant for hundreds of years, from the Chalcolithic period to the Middle Bronze age, when it was destroyed and not resettled for some five to six hundred years (almost skipping the Late Bronze age entirely, with settlement only into the Iron Age). Based on how the Cities of the Plain are described in the Bible (Sodom appears on its own, then “Sodom and Gomorrah”, then “Sodom, Gomorrah, Admah, and Zeboiim”), it seems probably that Sodom was the largest, with a satellite city of Gomorrah, followed by Admah with a satellite cities (or cities, the -iim is plural in Hebrew), so Tall el-Hammam was identified as Sodom, with three nearby talls (Tall Kufrein, Tall Nimrein, and Talls Mustah & Bleibel) that showed the same pattern of destruction being identified as the other three cities.

A close-up of the region with Tall el-Hamma (lower right) and Tall Khufrein (upper left) outlined. Tall el-Hammam is considerably larger, and was the largest site in the southern Levant prior to its destruction in the Middle Bronze age.

Tall Khufrein (Gomorrah?), seen from atop Tall el-Hammam. (The hill in between looks like another archaeological site, but is private land and has never been excavated.)

Now, when we talk about destruction, it's important to remember that cities in the ancient world get destroyed all the time. A city being destroyed is hardly news, and on its own, says little. However, because cities get destroyed so often, archaeologists have a pretty good picture of the various ways it usually happens: to earthquake, or fire (perhaps caused by earthquake), or war (or more nebulous causes like climate change or people just sort of abandoning it).

Prior to the current excavation beginning in 2006, a previous excavation of Tall eh-Hammam had noted an occupation gap, termed (perhaps informally, I'm not sure) the “Late Bronze gap.” In practice, this gap means basically no one occupied the site for around five or six centuries after its destruction in the Middle Bronze. That is somewhat odd, because it's a fantastic site for a city in the old world: on a defensible hill, on the Jordan floodplain with great agricultural opportunities, with a spring for fresh water and a wadi nearby, at the confluence of the trade routes running north-south and east-west (all of which helps explain why it was so large and prosperous for so long). Often when cities are destroyed in the ancient world, people come and rebuild them basically immediately – brush the collapsed stone off the foundations, clean up a bit, and build right back. (That or the city becomes permanently uninhabited – breaks happen, but not usually for five hundred years, on prime real estate.)

As mentioned, the other sites identified as the remaining cities of the plain show the same destruction in the Middle Bronze with either no resettlement throughout the Late Bronze age, or ever. Interestingly, even Jericho, across the Jordan river on the other side of the flood plain, shows signs of destruction around this time, though with a much shorter or non-existent gap in resettlement. This is hardly conclusive evidence, but it's certainly odd: what would keep people away from the best real estate in the southern Levant for so long? And after sixteen seasons of excavation, a picture has started to emerge, of a destruction so overwhelming and unusual that people may simply have avoided the area out of fear (and also, possibly, cropland getting salted to a level which would've prevented growing various cereal crops – we'll get to that later).

What was that destruction? Some seventeen lines of evidence all point towards it being something like a Tunguska-sized airburst event, but this post is getting long enough as it is, so it'll get a post of its own. A hui hou!