Wednesday, July 1, 2015

The Leap Second CAPTURED

I am sure many of you have heard the news that today is an unusual day. Unusual because it is one second longer than every other day this year. This extra 'leap second' was thrown in at 9:59am Sydney time, making the 59th minute a very special 61 second minute. For any time freaks or radio addicts out there this is a big event, because it is single unique second that occurs only once every four years.

Right now, some of you might be asking: "So what's the big deal?"

Well it's simple. For centuries we regarded the sun as the most accurate clock in our universe. We set our timepieces against it. However, in the early 1800s advances in mechanical clocks led to the realisation that earth's rotation around the sun is slwoing down. We humble humans had produced clocks of greater accuracy than every before, an amazing achievement!

Our achievements in timekeeping didn't stop there though. Around 1940 the atomic clock was developed. Millions of times more accurate than a mechanical watch, the atomic clock became our new time standard. We measured the error in Earth's solar rotation: our Earth is slowing down by a quarter of a second every year. This presented a problem: how to keep our Earth 'on time' on its orbit of the sun. The timekeeping was no longer a matter of 'us' being late, but the Earth being late. Thus the leap second was born.

The creation of the leap second has proved controversial. Some scientists say we shouldn't worry about reconciling atomic with with earth/sun time at all. This makes today's leap second extra special, because it could be the last leap second of all. The end of an era in the history of human timekeeping.

I for one couldn't miss it. This morning I locked myself away with my radio. My plan? To capture that second in real time, and frame it as proof for posterity that it really happened.

To do so I tuned my short wave receiver to the International Time and Standard frequency of exactly 15mhz. On that frequency a transmitter located in Hawaii called WWVH sends out a time radio signal. I then processed the received signal with a piece of software that graphically displays the signal's audio component. The snapshot this created is simple proof of this uniquely lengthened 59th minute.

Was it difficult? The best analogy I can think of would be likening it to trying to photograph a meteorite. Not only do you need the best camera equipment, but also you have to hope for perfect conditions, no clear skies, no photo. Even with perfect conditions you would still need to know exactly when and where to look to find your target. In the end if the light from the meteor or in my case the signal from Hawaii was just too weak, then all efforts would have been in vain.

Luckily for me, although the signal wasn't strong, it was just strong enough. I sat listening to the signal from 8am, and sure enough could hear a pre-recorded message telling me that UT1 time would be adjusted for a leap second at 00:00 GMT. The event was on as scheduled, I just needed a bit of luck to catch it.

BEEP. The time signal appeared on the spectrum timeline, seemingly at precisely 10:00am. I took my snapshot and looked closer. The signal sat slightly off the time mark. I've got it!

The addition of just one second in 125 million may seem insignificant. Yet to me it is not. It is a testament to our mastery of time. We may not have any idea what time is all about, or what we are all about for that matter, but at least we are getting better at measuring it.

What an exciting journey!

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