If you are confused check with the sun

Carry a compass to help you along

Neither of those is a particularly good strategy here.

The sun doesn’t set on a daily basis; it sets once a year. Every day it stays almost at the same level and circles around. I expect that a long-term resident would be abe to tell time by noting where the sun was relative to the station itself; right now it’s about 17:15, and the sun is shining almost directly in the windows of the galley, on the Beer Can end of the station. That should stay constant through the days when the sun is actually visible.

My officemate, Daniel, and I don’t seem to be able to figure out which direction the sun goes around in the sky. For my part, I say that the reason clocks go clockwise is that in the default hemisphere sundials go clockwise. In this hemisphere they go counter-clockwise, which means the sun itself should be going clockwise. Daniel isn’t convinced it’s different in the two hemispheres. He’s been here several summers, but since we work in mostly-windowless IT, we don’t actually see the sun all that much. I’ll quiz a few outdoor workers at dinner. And make a point of looking out the galley windows again, too.

A compass isn’t a lot of help either. The magnetic poles move year to year, for one thing. The south magnetic pole is somewhere near 137E 64S. That’s barely in the antarctic circle up at 66.5S or so. Crazy. Well, actually it would be kind of convenient, since it’s so far away from 90S, to use as a reference around 90S. Magnetic South would make a nice standard for the small area the south pole station encompasses. But that isn’t the reference used.

Talking about directions here, we use the prime meridian — zero degrees, through  — as the reference for “grid north”. Standing at or near the south pole, pretending the world is flat, “north” means “parallel to the prime meridian, pointing to the equator”. And the other directions follow: “east” is at 90E, “west” is 90W, and “south” is what’s left. Maps are typically oriented in the north-hegemonistic fashion, north up.

It might be clever to use “solar noon” for our time. My mind boggles a little, but you could call “sunrise” the time when the sun is grid east and “sunset” the time when the sun is grid west. And if Daniel and I knew which way it went, I’d be able to tell you if “noon” would be the sun at grid north or grid south. But we don’t, so that doesn’t matter. Time zones are really political markings, not scientific. All of China is in one time zone, because that’s convenient. In the US, time zones snake around state borders [mostly] because that’s convenient. Since the two main off-continent points of contact for the US Antarctic Program are Denver, CO, and Christchurch, New Zealand, one of those would be convenient. And Christchurch it is! The local time here is local New Zealand time, including changes for Daylight Savings Time.

But oddly, the phones are all Denver. We get wrong numbers, and it’s kind of hard to convince someone that they aren’t talking to Uncle Milt, but the IT Helpdesk at the South Pole. If you want to phone me, let me know, and we can arrange something.

http://www.southpolestation.com/ is a wonderful resource about the station, and the source of all the maps.

Thanks to Stuart Marks for asking.

And I am right-but-wrong about sundials. I think.

Advertisements

6 responses to “If you are confused check with the sun

  1. Thanks! Very interesting. Yes, I think you’re right-but-wrong about the motion of the Sun. Looking “down” on the Earth from above the North Pole, the Earth rotates counterclockwise. To an observer standing at the North Pole, the Sun would therefore apparently revolve around clockwise. If a sundial (gnomon) were placed at the North Pole, the shadow would point away from the Sun, obviously, but it too would travel clockwise.

    Now at the South Pole the motion of the Earth and Sun are of course the same, but an observer standing at the South Pole is “upside down” relative to an observer standing at the North Pole, so the Sun would appear to revolve counter-clockwise around a South Pole observer. (And so would a gnomon’s shadow.)

    So you’re right about the motion of the shadow of a sundial, but the motion of that shadow is the same as the motion of the Sun, regardless of which hemisphere.

    Yeah this is all kind of mind-bending. Love to hear more!

  2. Well, you’ve answered the question I was saving up, about what local coordinate system do you use to navigate around the station.

    If you just watch the sun, or a shadow, for about ten minutes, you ought to be able to detect it moving to the left around the sky. Whether you call this “clockwise” or “counterclockwise” depends on whether you imagine yourself looking down at the ground or up at the sky.

    I would love to see a video of somebody walking a GPS receiver around the geographic pole, to watch the longitude tick all the way around.

  3. I was mildly amused when i read that my new telecom provider did not plan to look into discounted rates for calls to Antarctica. Now i can be disappointed.

    Glad to find that i can read up on how you’re doing!

    http://corp.sonic.net/ceo/2012/10/09/fusion-borderless-calling-expansion/ – “* Apologies to the roughly 3,687 scientists and staff at the various Antarctic research stations, and even deeper apologies to the 964 who typically stay through the long and isolated winter. I imagine you would really appreciate a call from one of our friendly Fusion members. But, your telephone service is all satellite delivery, so I am going to pretend that you aren’t really a continent. From the perspective of free Fusion Borderless calls to land lines, you’re not. Sorry!”

  4. Barry is, I think, probably right about clocks going clockwise because of the usual sort of sundial in the northern hemisphere, one whose “face” is horizontal. But there’s another common type of sundial which is mounted on a south-facing wall, and in the northern hemisphere its dial goes counter-clockwise.
    See http://www.sunshadow.co.uk/ and

    Now are you even more confused?

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s