Leap Second

Unbeknownst to most of us there are a bunch of clever people out there, many of them at NASA, who carefully look after our time for us. We're all aware, hopefully, that every four years, with some exceptions, we have an extra day added to the year in the form of February 29th. This is because the time it takes the earth to orbit the sun is actually nearer 365.25 days than plain old 365. Nothing too complicated about that.

However, the time it takes the earth to spin around its axis is not precisely 24 hours, or 86,400 seconds; it's more like 86,400.002 seconds. What complicates things, though, is that it isn't always that long, it varies, and no one can predict how long it will be in the future. This is because plate tectonics, the movement of the major landmasses around the surface of the earth, and weather patterns can all have an effect and both of these are inherently unpredictable.

The main reason that days are longer, and generally getting longer still, than they used to be is that the moon is constantly tugging on the earth. Its gravity pulls and drags the oceans over the surface of the planet; this gives us tides but that friction of the water moving over the earth also slows our rotation down. In a very, very, very, very long time the earth will stop rotating with respect to the moon and our lunar companion will only ever be visible from half of the planet. Like I said, though, we're talking a long time until this happens, billions of years, indeed some people say it will never happen as our oceans will have long evaporated away by then and the planet will be all but a dead rock so, y'know, don't panic or anything.

None of this would make a blind bit of difference to our lives if it wasn't for the fact that little things like the internet and the financial sector all run on software in which good time keeping is critical. These systems tend to run on atomic time, the time as measured by the insane accuracy of modern atomic clocks which work by measuring the vibrations of caesium atoms and such. These modern clocks, which look nothing like clocks, are accurate to about 1 second in a billion years or so; the earth itself is not nearly so reliable a time keeper and so atomic time and astronomical time slowly drift apart. When the difference gets to about 0.9 seconds the International Earth Rotation and Reference Systems Service will make a recommendation to the International Telecommunications Union, who's final decision it is, to add an additional second.

Which brings me back to those clever folk at NASA. They are some of the people who, using radio telescopes and quasars, can precisely measure just how long our day has been with a technique called Very Long Baseline Interferometry. You can see a nice little cartoon from NASA below where they pithily explain exactly how that works. All of which just leaves one question: what to do with that extra second on Tuesday night?

Brick Lane By Night

Last Saturday night I joined up with the people from London Photo Walk to go on an all night solstice walk. We covered about 23km over 11hrs or so. It was a long but extremely rewarding night and I look forward to doing it again next year.

Given that this took place all through the night exposures were all very long, generally 15-30 seconds. It was also quite difficult to even know exactly what you were pointing your lens at as it was so dark in some of the back alleys and so composition wasn't always straightforward. This meant that over the 11hrs I only took about 100 photos; but there was a definite benefit to this. It was a bit like shooting with film, you were forced to put a lot more thought into what you were doing. If you pressed the shutter at the wrong time then you wasted half a minute of your life, which may not sound like much but it is quite the motivator when the wind is blowing at three in the morning.

As I said, we covered a lot of ground that night but the four photos in this post are all from the ever fascinating Brick Lane; one of my favourite streets in the world. Endlessly interesting and always full of life I have spent countless hours walking it's length, generally in the dead of night, but this was the first time I had ever taken my camera with me. I think it paid dividends. It isn't very difficult to make great art look good and obviously street art lends itself to street photography, something I normally struggle with.

Except for the fox, each of the pictures here have undergone quite a lot of post processing to bring out the best in them, or, rather, conceal the worst in them. These pictures were quite busy and messy to start with and mostly what I have done is to crop them down and remove colours to hopefully simplify them and make them easier on the eye. The shot below is a great example of where the original exposure wasn't up to snuff. There was different coloured crap all over the floor, the edges of other artworks to either side and and some unattractive lintels over the top. I cropped out most of all that, made it black and white to remove the distracting colours and then just allowed the reds and yellows to come through to keep it simple. Hopefully the result is a more satisfying picture that allows you to focus on the graffiti. It's a cliche but less is often more.