« Private fears in public places | Main | The life of Bryan »

Half time

I can't remember when I learned that the world was neatly divided up into 24 steps that translated geographically into time zones, so I must have been very young. The rampant spread of international communications and travel probably means most people learn pretty early that time-keeping moves across the globe. The all-day coverage of the turn of the millennium was a great worked example: every hour, CNN would turn to a new group of cities in a new time zone where it was midnight all over again.

It was only this week that I became more forcibly aware of the areas of the world where this neatly stepped, digital-friendly way of looking at things breaks down. To wit: Adelaide, South Australia, where time slips away at a half-hour offset from everyone else. Here, depending on the time of year it's anything from eight and a half to ten and a half hours ahead of London, 13 and a half to 15 and a half hours ahead of New York. The stray half-hour (plus the two countries' recent asynchronous moves to winter and summer timer respectively) makes calculating the time "back home" remarkably more confusing than you'd think it should be.

Wikipedia informs me that there are all sorts of oddities I've never contemplated, some of them embarrassing omissions from my general knowledge. Prime among the latter are India and Sri Lanka, which I'd managed never to notice in 60 years also live on a half-hour offset (UTC+5:30). If you're looking at the world in those 24 steps, India spans two time zones, but apparently saw compromising on a midway average, the half-hour offset, as an attractive way to help unify a newly independent country.

More oddities: two zones in the Pacific that lie on a north-south plane have the same time but dates a day apart. For similar reasons, the world actually has 26 hourly time zones, not 24. And then there's New Zealand's Chatham Islands, which lope along on a quarter-hour offset (UTC+12:45).

All of this is the standardized - analogous to digitized - version of time. In the analog world that pre-dated the need for standardized time created in the 19th century by the railways' need for predictable schedules, time was defined by whatever your nearest sundial said. Noon was when the sun said it was, and time was inextricably linked to the movements of sun, planets, and stars in the physical world.

In 2005, I wrote about efforts by US scientists to eliminate leap seconds. The incongruity was fun: scientists, engineers, the ITU, and national governments, were all spending years squabbling over seconds. Now it's decades: the issue has been put off and left unresolved, and there's a new vote in 2015. Yes: it's' now decades they've spent squabbling over seconds.

But of course the debate isn't really about seconds: it's about whether to take yet another step in divorcing time as we use, understand, and measure it from its natural origins. The issue is the earth's slowing rotation, which means that standardized time has to be periodically corrected - by adding leap seconds - to bring it back into alignment. The proposed redefinition of the second would eliminate this problem. Currently and since 1967, a second is defined as 1/86,400 of the mean solar day; the replacement would define it by the rate of decay of caesium atoms. Either decision creates problems for someone: astronomers, GPS, other navigational instruments, and satellite communications all are affected by how time is defined.

It's difficult for a non-expert to evaluate the validity of the claims on either side or which would suffer more if the principle they oppose is adopted. On a personal level, there's no need for most of us to care as long as the stuff we use every day keeps working. The average person's uses of time do not require the level of precision that GPS satellites and giant telescopes do. Does either of these arcane proposals really affect when you have lunch?

And yet emotionally, the argument that man has used sun and stars for navigation for tens of thousands of years, and we should not lightly abandon that physical connection has a certain resonance. For one thing, I like the notion that the correct time can be derived with some precision from devices that one person can create with little more than a stick and a piece of string - or machine tools and precision drawings. The ability to derive the basic principles of science the same way our forebears did is important.

We forget physics at our peril. Physics is why the traders in Michael Lewis's Flash Boys sought to shave inches off the fiber connections that connected them to the exchanges. Physics is why the 2014 map of undersea cables looks a lot like the 1891 map of world telegraph lines. One look at either map, and you know precisely where to put the wiretaps (or the backhoes).

When we talk about taking back the Net, physics matters. We can lobby for better law; we can promote different norms; and we can change the values embedded in computer code. About physics, we can't do a damn thing.


Wendy M. Grossman is the 2013 winner of the Enigma Award. Her Web site has an extensive archive of her books, articles, and music, and an archive of earlier columns in this series. Stories about the border wars between cyberspace and real life are posted occasionally during the week at the net.wars Pinboard - or follow on Twitter.


TrackBack

TrackBack URL for this entry:
http://WWW.pelicancrossing.net/cgi-sys/cgiwrap/wendyg/managed-mt/mt-tb.cgi/532

Post a comment

(If you haven't left a comment here before, you may need to be approved by the site owner before your comment will appear. Until then, it won't appear on the entry. Thanks for waiting.)