Well, even if the OED defines them as such, neither the September equinox nor the just-past March variety actually counts an exactly symmetrical twelve hours of daylight and darkness. Often, the fussy details of things in astronomy (like whether an equinox is labelled as spring, or just March) are related to an observers location on Earth. This time, though, it mainly matters that this was only the spring equinox if you live north of the equator, so identifying it by its month is less hemisphere-centric. Which is absolutely a word.

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Walnuts and engagement

3 October 2009

One of the things I really like about Corvallis is that so many different trees flourish here; there are at least two different kinds of walnut within a block of our house. We’ve harvested some already for eating, but there is a slightly menacing corollary of that bounty manifesting itself about this time of year. As if the hazards of being hit by a falling walnut or having your feet roll out from underneath you on a carpet of them wasn’t bad enough, when shedding fruit in great quantities, these trees draw crows in flocks large enough to qualify as Hitchcockian.

In attempting to devour the crop, crows can be seen trying to crack walnuts by attempting to pin them between their feet to peck at, or drop them from lamp posts, or wedge them in the manhole cover, or (my personal favorite) hurl them at human interlopers. Displaying an amazing variety of tactics, and using elements of the natural environment to their advantage, as well as (superficially, at least) learning from past mistakes presents something very close to empiricism.

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Happy September equinox, everyone.

One of the cool things about this day is that it has a fairly high profile on the common, demi-Gregorian calendar, the equinoxes perhaps figuring even larger than solstices in my casual surveys. Another one is that it is only the autumnal equinox if you live north of the equator: otherwise, it is the vernal kind.

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Generally speaking, it is unusual for ‘economic stimulus jobs’ and ‘underwater robots’ to appear in the same sentence. For a month this summer, though, those two concepts went hand-in-claw at a camp organized by Linn-Benton Community College staff and students. As a part of the Oregon Underwater Volcanic Exploration Team, high school students from all over the state received training in job skills like electrical circuit design, budget-keeping, and geographic information systems as they built and operated research submersibles called ROVs. The high schoolers were nominated by teachers and counselors in their home towns, and spent six days camping on Paulina Lake inside Newberry National Volcanic Monument east of LaPine. Each student designed and built their own ROV, which they got to take home at the end of the week. Money for the project came from a grant by The Oregon Consortium and the Oregon Workforce Alliance, by way of legislative money for job training in Oregon, where high-tech job growth requires constant workforce training.

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Wayfinding and waves

27 April 2009

I once had a brief discussion with a much smarter fellow than myself wherein he argued that four was an arbitrary number for cardinal geographic directions. While I concede (now, as I didn’t then) that he is correct from a geometric point of view, there seems to be at least one evident physical reason for the choice: one direction each for sunrise, sunset, and halfway from each to the other.

While Guy Ottewell gives a potential (if esoteric) thesis for why A is the first letter of a couple of different alphabets, I have nothing like the speculative erudition to say whether my guess holds any water. I do know, though, that while useful direction finding tools can be simple, they can also be arbitrary. Polynesian navigators use celestial coordinate systems shaped from the rising and setting of the Sun and other stars, and these coordinate systems are sometimes symmetrical and even, but not always. Navigators also shape their course based upon other information including clouds, wind, sea critters, birds, and other factors.

One of these other factors was brought into sharper focus for me as I flew from Minneapolis to Cleveland last week, passing over Lakes Michigan and Erie on the way. As far as I’ve been able to figure, this trip was at a similar altitude to those from Hilo to Honolulu, flying at approximately 30,000 feet. What struck me as different, though, was that while I was used to seeing the Pacific Ocean with increasing complexity as more and different sets of waves gradually revealed themselves crossing and rolling on its slightly rough skin, I didn’t see any texture of swells on the two Great Lakes.

Having grown up about six blocks from the edge of Lake Superior, and spent time tagging along on boats with my father from a tender age, I can attest that the Great Lakes do possess waves of sufficient size as to be seen from the air. Those waves might not be the sixty-foot seas of the northern Pacific that cause the weather announcers to doubt their script in the middle of reading it, or even the massive rollers that create the fantastic offshore breaks at Peahi near Maui or Mavericks off California, but Great Lakes waves have sunk ships and otherwise imposed their presence in plenty of ways. In short, I was surprised that I couldn’t see anything from the air, even on a relatively calm day.

My guess as to the cause is something called fetch. In this case a noun, fetch refers to the distance across the water that a wind blowing in that direction has to build up waves. While modeling the problem quantitatively is by nature more complicated, fetch can have an effect equal to that of the speed of the wind. It is the biggest reason why small lakes don’t have big waves. Wind speed and fetch can also affect the rate at which waves come in, their period, a characteristic well known and scrutinized by surfers everywhere.

I’ll do some checking with other resources, but I would guess that the tapestry of overlaid swells that help Polynesian navigators orient themselves on the Pacific was also present on Lake Michigan a week ago, and that the chief difference in appearance wasn’t caused by a difference in height of the waves, but rather in their frequency. Lake Michigan is long and thin, perhaps 85 miles wide from Milwaukee, WI on the west side to Grand Haven, MI on the east, but 280 miles north to south from rural Summer Island on the UP to industrial Gary, Indiana. Thus, when the wind is blowing most directions, there is fairly little water to build up long distances between waves. Only if the wind blows due north or due south (winds being named for the direction they are blowing _from_, in most cases) is their enough fetch to produce swells wide enough to be seen from the air.

Any kindly contributors with more knowledge are invited to comment, particularly if you have done some calculations. I am halfway through building a KML file for the trip, and will post it to the comments when it’s finished.

Well, if I can say something without jinxing it, it appears as though our two weeks of winter may be over. Not but what it won’t be grey and rainy for a while yet, but the incipient buds are swelling more greenly on their socially networked branches. The leaves cluttering the sidewalks are from the sweetgums, and most of them only just fell within the last month. We’ve had some sunny warmth here and there, and while I haven’t seen any hummingbirds yet, the Steller’s Jays have been joined by squads of robins.

But the thing that really brought a sense of seasonal change for me was at the end of the cold snap we had in December. Hardly seems fair of me to use that term, when Fairbanks has been pretty chilly by comparison, but people take notice when we get a weeks worth of heavy frosts in Corvallis. At any rate, on about 29 December, I woke to find cirrus clouds covering most of the sky, and causing a strong, beautiful 22 1/2 degree halo around the Sun. I’ve long since given up any pretensions to being able to photograph such phenomena, so I contented myself with staring upward for several blocks on the way to work.

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(mostly) Northern roundup

14 November 2008

Kyle Hopkins kicks ASS! Just heard him interviewed on NPR about an Alaska politics article he wrote for the ADN, and I was both thrilled to hear about someone I had lost touch with, and relieved that so sharp a wit is covering the important Stevens-Begich Senate race closely.

Begin obligatory election response: pretty weird that the three most hotly contested (or at least most drawn-out) Senate races were the three states I was most interested in: AK (see above), MN, OR. End obligatory election response.

I’m just starting Rashid Khalidi’s book Resurrecting Empire, which doesn’t seem designed to flagellate liberal guilt so much as actually educate a willing audience about colonialist history from the Eastern Mediterranean to the Indian subcontinent. A good book, and I liked it even more when I found out that he’s almost as dangerous as Bill Ayers.

National Geographic has a ten-page cover article on light pollution out this month, and we happily have our first clear night in about two weeks (not that that’s a record or anything–Alicia tells me that she remembers Kodiak going for something like sixty straight days of rain once, and nobody was talking about records being broken) Still, though, it is crisp and cool tonight. Jupiter looked bright until I saw Venus, and Manaiakalani is setting in the west as Ke ka o ka Makali`i is rising in the east. Even though I know something about how bad light pollution really is, I am reassured that I showed my nephew the same two planets and some of the same stars from the East River about a month ago.

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