This is one mean solar day. I mean its hot.

The reason, well we've not been this close to the Equator since about a week before we got to French Polynesia. Then, unlike now the sun was tracking north. As we've been as far as 20° south of the Equator its been Winter down there.

Algal Blooms and Cruising Chutes

We're now up at less than 11° south, and the sun is now south of the Equator. Its very light winds, shallow water. The temperature sensor is part of the log. That's not a piece of wood, though that's were it gets its name, nor the thing Capitan Kirk spoke to as a voice-over in Star Trek. Its a little paddle wheel under the hull that tell you how fast and how far. Its made by raymarine so, as previously mentioned, its got more bugs than windows Vista. Back to the point. Deep ocean's the sun warms the surface, shallow seas don't have icy depths so get hotter.

For those of you who've forgotten your school geography/science, here comes the science. The Earth goes round and round spinning on its axis, the north and south poles. It also goes round the sun. The earth's axis is not quite at the same angle as the axis of the earth's orbit of the sun. So during the English winter solstice the sun is 24 degrees south of the equator at local noon. On June 21's its over the tropic of cancer 24° north of the equator.

That means at the Autumn (norther hemiphere) equinox its directly over the Equator. Were a week aflter that so its, very soon going to be right over head.

In short its hot.

For those of you asking the question "what the hell does 'sidereal time' mean" or even, for the more enlightened, "what the hell has sidereal time got to do with this blog post". The answer to the second is not much, but I must explain my self answering the first and proving I'm not an ignorant savage.

What's a day? Well at Noon the Sun is directly over head - or highest in the sky unless its an equinox and your on the equator, or even a solstice and your on the right tropic. So every day the earth goes round once. Sun over head to over head. This is a day, or technically a solar day. Hang on I here you cry, but the earth is going round the sun, so we will have move about a degree of our orbit round the sun. (we go around the sun every year. 1 year = 365days. 360° in a circle, so roughly a degree a day). So the sun should be 1 degree off over head for a day. We work to the solar day cos its easier. If you were to work by the time it takes for the earth to rotate one complete circle, this day would be slightly different length to the one your used to. This is called a sidereal day.

You've learned something today. Of course after we got atomic clocks, we realised that the earth's spin isn't entirely consistent, not every day is quite the same length if you measure it accurately enough so we talk about the average or mean solar day. I was making a physicists joke there with the heat gag.