Shallow Thoughts : : Mar

Akkana's Musings on Open Source Computing and Technology, Science, and Nature.

Mon, 30 Mar 2020

D is for Devilish Place Names

It was surprisingly hard to come up with a "D" to write about, without descending into Data geekery (always a temptation). Though you may decide I've done that anyway with today's topic.

Out for a scenic drive to shake off some of the house-bound cobwebs, I got to thinking about how so many places are named after the Devil. California was full of them -- the Devil's Punchbowl, the Devil's Postpile, and so forth -- and nearly every western National Park has at least one devilish feature.

How many are there really? Happily, there's an easy way to answer questions like this: the Geographic Names page on the USGS website, which hosts the Geographic Names Information System (GNIS). You can download entire place name files for a state, or you can search for place name matches at: GNIS Feature Search.

When I searched there for "devil", I got 1883 hits -- but many of them don't actually include the word "Devil". What, are they taking lessons from Google about searching for things that don't actually match the search terms?

I decided I wanted to download the results so I could count them more easily. The page offers View & Print all or Save as pipe "|" delimited file. I chose to save the file.

Read more ...

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[ 16:30 Mar 30, 2020    More linux/cmdline | permalink to this entry | ]

Thu, 26 Mar 2020

C is for Cabezon (and the Census too)

... You thought C would be coronavirus or COVID-19, I bet!

Well, I won't pretend I'm not as obsessed with it as everybody else. Of course I am. But, house-bound as we all are now, let's try to think about other things at least now and then. It's healthier.

[Cabezon Peak] One of the distinctive peaks here in northern New Mexico is a butte called Cabezón, west of the Jemez near Cuba.

It's a volcanic neck: the core of an old volcano, part of the Mt Taylor volcanic field. Once a basalt volcano stops erupting, the lava sitting inside it slowly cools and solidifies. Then, over time, the outside of the volcano erodes away, leaving the hard basalt that used to be lava in the throat of the volcano. It's the same process that made Tunyo or Black Mesa, the butte between Los Alamos and Española that's been featured in so many movies, and the same process that made the spectacular Shiprock.

Dave and I have driven past Cabezón peak several times, but haven't yet actually explored it. Supposedly there's a trail and you can climb to the top (reports vary on how difficult the climb is). One of these days.

Last week, Dave was poking around in a Spanish dictionary and discovered that -ón in Spanish is a suffix that denotes something larger. So, since cabeza means head, cabezón means big head. (Looking for confirmation on that, I found this useful page on 18 Spanish Suffixes You’ll Never Want to Let Go Of.) Apparently it can also mean stubborn, ditzy, or just having big hair.

But hearing that cabezón meant big head took me back to my childhood, and another meaning of cabezón.

When I was maybe ten, my father decided to take up fishing. He bought a rod and reel, and brought me along as we headed out to the docks (I don't remember where, but we were in Los Angeles, so it was probably somewhere around Santa Monica or San Pedro).

This didn't last long as a hobby; I don't think dad was cut out for fishing. And mostly he didn't catch anything. But on one of our last fishing trips, he caught a fish. An amazing fish. It wasn't especially big, maybe fourteen inches or so. It had a big head and a triangular body, with a flat belly as the base of the triangle. It had weird fins. It was dark olive green on two sides of the triangle, with a dull yellow belly. It looked prehistoric, and sent me running off to the books when we got home to make sure we hadn't caught a coelocanth.

[Cabezon, Scorpaenichthys marmoratus] After some research at the library (this was way pre internet), my father concluded that he'd caught something called, you guessed it, a cabezón.

Searching for photos now, I'm not so sure that's right. None of the photos I've found look that much like the fish I remember. But I can't find anything more likely candidates, either (though I'm wondering about the Pacific staghorn sculpin as a possibility). I guess fish identification even now in the age of Google isn't all that much easier than it was in the seventies.

I don't think we ever ate the fish. It sat in his freezer for quite a while while he tried to identify it, and I'm not sure what happened after that.

So maybe I've seen a cabezón fish, and maybe I haven't. But it was fun to learn about the -ón suffix in Spanish, to find out the meaning of the name for that distinctive butte out near Cuba. One of these days Dave and I will go hike it. And if we make it to the top, we'll try not to get big heads about it.

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[ 19:17 Mar 26, 2020    More nature | permalink to this entry | ]

Sun, 22 Mar 2020

B is for Badlands

[hiking in Nambe Badlands] The idea of blogging the alphabet came from a conversation during a hike in Nambe Badlands. It's beautiful a hike that we don't do very often, about 40 minutes from Los Alamos.

"Badlands" is a term for any sort of soft, dry, eroded terrain: a place of mostly dirt and loosely consolodated sandstone, where the terrain erodes into a maze of rounded hills, steep gullies and arroyos, with occasional pillars where harder rocks emerge.

Badlands are often fairly colorful due to the mixture of different rock and soil types. Arizona's Painted Desert, with its stripes of red, white and green, is a famous example. The colors around Nambe and the rest of the Española valley is more subtle: mostly reds, tans, yellows with a few bright white veins running through.

[Nambe Badlands white rim layer; Los Alamos in the background] One thing you get in the badlands is views. In the image at left, we're looking southwest past the "barrancas" of Pojoaque. You can see the Pajarito plateau -- the line of white buildings is part of LANL, fairly near my house in White Rock -- and beyond it, the Jemez mountains, Out of the photo behind us are the Sangre de Cristos, running up toward Taos and eventually Colorado.

[Nambe Badlands white rim gleams in the distance] The badlands themselves are interesting too. They're mostly Santa Fe Group sediments, eroded primarily from the Sangres with a little contribution from the Jemez. In this area, there's a prominent white layer running through. Since it's harder than the dirt on either side of it, it tends to make a "white rim" reminiscent of the famous Canyonlands White Rim, but of course the rock itself is very different. This white rim, while harder than the normal badlands dirt, is still relatively soft, flaky; it erodes to a powder anywhere where it's exposed.

Geology books don't cover this area, but as best I can determine, from papers online, the white layer is probably an ash layer that's part of the Skull Ridge group of the Tesuque formation (those are all finer gradations of the Santa Fe Group). There are four white ash layers, probably erupted from 13-16 million years ago (estimates vary quite a bit, but middle Miocene), possibly from Nevada. So although the white ash is volcanic, it's apparently quite a bit older than most of the Jemez and comes from somewhere else entirely.

It's hard to be sure: I wish geological papers included better maps. In the one Field Geology class I had the opportunity to take, we spent most of our time making maps, and I suspect maps are a big part of what most professional geologists do; but somehow, the geology papers online seem remarkably lacking in maps. Oh, well.

[Nambe Badlands Owl Tower] We climbed up to a high lookout for lunch, during which Charlie, our best birder, was scanning with binoculars and discovered an owl sitting in the tower across from our lunch spot. Alas, due to coronavirus "social distancing" concerns, she couldn't pass her binoculars around, but I was able to see the owl, just barely, with the little monocular I keep in my pack. After some debate over its size, and scrutinizing the photos (not good enough to be worth sharing) afterward, Charlie concluded (and I agree) it was a great horned owl.

[Ken inspects a Nambe Badlands formation] Badlands exploring is fun; aside from spectacular views, there are always interesting hoodooes and other rock formations to inspect. We did a relatively easy 5.5-mile loop, but there are plenty of other trails in the badlands that I'd like to explore some day.

A few relevant papers I found:

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[ 12:02 Mar 22, 2020    More nature | permalink to this entry | ]

Wed, 18 Mar 2020

A is for Absentee Ballot

We're "praticing social distancing" with the COVID-19 virus active in New Mexico ... but fortunately, that doesn't mean we can't hike. It might be the most healthy thing we can do, as long as we all keep our distance from each other and don't carpool.

On this week's hike, someone told me about a fun activity: since a lot of her friends are stuck at home, they're trading emails where each day, everybody writes about something starting with a new letter of the alphabet.

Sounds like fun! So I'm going to join the game here on my blog. I'm not going to try for daily posts; I expect to post roughly twice a week, usually on light topics, not geeky tech articles.

I'll lead off today with a short note: a reminder to everyone to sign up for an absentee ballot, if your state allows that, so you can vote by mail rather than going to a polling place in person.

In this time of social distancing, you don't want to be at a crowded polling place touching the same screens or pens that everyone else has touched before you; and it would be better if poll workers weren't required to be there either. It would be so much better if we all voted by mail.

When Dave and I lived in California, the state had just switched to what they called "permanent absentee ballots": at least in the bay area, ballots were automatically sent to all voters. You could fill the ballot out at home, and then you had the choice of mailing them in or dropping them off at the nearest polling place. (This was thanks to our excellent then-Secretary of State Debra Bowen, who also fought against no-paper-trail voting machines and for increased ballot access.)

New Mexico still uses in-person voting, though I'm happy to say we use paper ballots and allow absentee voting without requiring any excuse. But this year, it looks like New Mexico will be encouraging voting by mail; our Secretary of State has a FAQ | ABSENTEE VOTING FOR THE 2020 PRIMARY ELECTION. page with details on how to sign up, and you must request your ballot for the primary by May 28.

Check the rules for your state (assuming you're in the US). If you haven't voted in the primary yet, check now, since time may be running out! For the November general election, you probably have plenty of time.

And if your state doesn't allow no-excuse voting by mail / absentee ballots, this might be time to call your governor or lobby your state legislators asking for an exception. It's a critical health matter, this year.

[ 20:58 Mar 18, 2020    More politics | permalink to this entry | ]

Sun, 01 Mar 2020

Plotting Epicycles

Galen Gisler, our master of Planetarium Tricks, presented something strange and cool in his planetarium show last Friday.

[inner planet orbits from north ecliptic pole, with Venus pentagram] He'd been looking for a way to visualize the "Venus Pentagram", a regularity where Venus' inferior conjunctions -- the point where Venus is approximately between Earth and the Sun -- follow a cycle of five. If you plot the conjunction positions, you'll see a pentagram, and the sixth conjunction will be almost (but not quite) in the same place where the first one was. Supposedly many ancient civilizations supposedly knew about this pattern, though as Galen noted (and I'd also noticed when researching my Stonehenge talk), the evidence is sometimes spotty.

Galen's latest trick: he moved the planetarium's observer location up above the Earth's north ecliptic pole. Then he told the planetarium to looked back at the Earth and lock the observer's position so it moves along with the Earth; then he let the planets move in fast-forward, leaving trails so their motions were plotted.

The result was fascinating to watch. You could see the Venus pentagram easily as it made its five loops toward Earth, and the loops of all the other planets as their distance from Earth changed over the course of both Earth's orbits and theirs.

You can see the patterns they make at right, with the Venus pentagram marked (click on the image for a larger version). Venus' orbit is white, Mercury is yellow, Mars is red. If you're wondering why Venus' orbit seems to go inside Mercury's, remember: this is a geocentric model, so it's plotting distance from Earth, and Venus gets both closer to and farther from Earth than Mercury does.

He said he'd shown this to the high school astronomy club and their reaction was, "My, this is complicated." Indeed. It gives insight into what a difficult problem geocentric astronomers had in trying to model planetary motion, with their epicycles and other corrections.

Of course that made me want one of my own. It's neat to watch it in the planetarium, but you can't do that every day.

So: Python, Gtk/Cairo, and PyEphem. It's pretty simple, really. The goal is to plot planet positions as viewed from high above the north ecliptic pole: so for each time step, for each planet, compute its right ascension and distance (declination doesn't matter) and convert that to rectangular coordinates. Then draw a colored line from the planet's last X, Y position to the new one. Save all the coordinates in case the window needs to redraw.

[planet orbits from north ecliptic pole] At first I tried using Skyfield, the Python library which is supposed to replace PyEphem (written by the same author). But Skyfield, while it's probably more accurate, is much harder to use than PyEphem. It uses SPICE kernels (my blog post on SPICE, some SPICE examples and notes), which means there's no clear documentation or list of which kernels cover what. I tried the kernels mentioned in the Skyfield documentation, and after running for a while the program died with an error saying its model for Jupiter in the de421.bsp kernel wasn't good beyond 2471184.5 (October 9 2053).

Rather than spend half a day searching for other SPICE kernels, I gave up on Skyfield and rewrote the program to use PyEphem, which worked beautifully and amazed me with how much faster it was: I had to rewrite my GTK code to use a timer just to slow it down to where I could see the orbits as they developed!

It's fun to watch; maybe not quite as spacey as Galen's full-dome view in the planetarium, but a lot more convenient. You need Python 3, PyEphem and the usual GTK3 introspection modules; on Debian-based systems I think the python3-gi-cairo package will pull in most of them as dependencies.

Plot your own epicycles:

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[ 13:04 Mar 01, 2020    More science/astro | permalink to this entry | ]