You have GoT to be joking

It’s not my thing, but I do recognise that the drama series Game of Thrones is very much the zeitgeist, and that’s just fine. However, when the UN hasn’t quite got around to calling world leaders together to debate the latest pre-apocalyptic move by North Korea, but they’re still tweeting this sort of thing:

We’ll be having a special meeting of the Security Council to discuss the implications of using dragons in warfare, pursuant to the Geneva Convention. 

…I can’t help but think that things have gone a bit far.

Priorities, people. One of these things is actually real.

Tyre ski jump

You, like me, have often wondered which sort of tyre would fly furthest when sent down a (snow-free) ski slope. I know this, because a recent study on the causes of insomnia indicated that wondering about which sort of tyre would fly furthest when sent down a (snow-free) ski slope was given as a factor by almost 100% of respondents (n=1).

Don’t worry: you can sleep easy tonight: we’ve got you covered.

The six tyres you wanted to see tested are tested right here, and they’re each travelling at some considerable speed (like 140kph) when they reach the bottom end of the slope.

Yep, whether it’s the 11kg, low profile sports car tyre or the 225kg rubber from a monster truck, you’re going to know what sort of tyre flies furthest when sent down a (snow-free) ski slope, simply by watching this video.

And you also get to see what happens to the tyre once it has done its jump. Because stopping a tyre with that sort of mass, velocity (and therefore momentum) might prove to be quite a task.

So, so good.

Notes on Japanese ship-naming conventions

Yeah, I know. That title. You’re already disinterested, but hey – hang tight – you might just learn something today.
I know I did.

Japanese fishing vessels have been all over the news lately. If you count the one that ran aground on Clifton Beach last month and the one that was found drifting off the coast of Canada in April, that is.
The former has sadly dropped out of the news and even now, no-one is really sure how it ended up parked among the holiday homes of the German elite. The latter was a victim of the March 2011 tsunami and has been drifting across the Pacific ever since.

Their names: the Eihatsu Maru and the Ryou-Un-Maru. And I’ll use this handy opportunity to chuck the name of the only other Japanese fishing vessel I know in there too: the Meisho Maru 38. Some of that one lies aground near Cape Agulhas and has surely featured in many photographs, but most notably, this one:

Eagle-eyed readers should really give the eagle its eyes back, but in the meantime, they will have noticed the common “Maru” in the names of all these vessels, because eagles are good at spotting that sort of thing.

When you look  up Maru on Google translate, it tells you in mean “circle” and also, if you look a little below that, “suffix for ship names”. But why?

Well, god bless the internet, because Wikipedia can help us out with an answer on their helpfully named: “Japanese ship naming conventions” page, which discusses and explains Japanese ship naming conventions. And it tells us:

The word maru (meaning “circle”) is often attached to Japanese ship names. The first ship known to follow this convention was the Nippon Maru, flagship of daimyo Toyotomi Hideyoshi’s 16th century fleet. There are several theories which purport to explain this practice:

  • The most common is that ships were thought of as floating castles, and the word referred to the defensive “circles” or maru that protected the castle.
  • That the suffix -maru is often applied to words representing something that is beloved, and sailors applied this suffix to their ships.
  • That the term maru is used in divination and represents perfection or completeness, or the ship as a small world of its own.
  • A legend of Hakudo Maru, a celestial being that came to earth and taught humans how to build ships. It is said that the name maru is attached to a ship to secure celestial protection for it as it travels.
  • For the past few centuries, only non-warships bore the maru ending. It was intended to be used as a good hope naming convention that would allow the ship to leave port, travel the world, and return safely to home port: hence the complete circle arriving back to its origin unhurt.
  • Note also that Hinomaru or ‘sun-disc’ is a name often applied to the national flag of Japan.

Today commercial and private ships are still named using this convention.

Of course, there are many superstitions and traditions in Japanese society and there are probably (at least) an equal number in the seafaring community, so it seems perfectly reasonable that when these two behemoths of folklore come together, we get this well-observed custom of nomenclature.

That said, many of the reasons given above are centred around the protection of the vessel and its safe return to port and that hasn’t really held true for any of the ships I am aware of (n=3). Let’s not forget that one ended up on a local beach, another ended up on some fairly local rocks and another was sunk by the US Coastguard “for safety reasons” (and, let’s be absolutely honest here, fun).

Look, I recognise that it’s Friday afternoon and you aren’t in the mood to learn stuff. But you’ll be thanking the Japanese Seagods and 6000 miles… at your next pub quiz, believe me.

Assuming there’s a question about this sort of thing, of course.

Parents on Tour

As thos of you who follow me on twitter will probably know, my parents have been in New Zealand for the past few weeks. Fortunately, while they were in New Zealand at the time, they were some distance away from Christchurch when the earthquake struck. Even more fortunately, they were well gone from Japan – which they passed through en route – by the time that the tsunami struck there.
Here’s one of my Dad’s pictures of that country on a more peaceful day.

They are now in South Africa and while I can’t promise them snow-capped volcanoes, I can – with some degree of certainty – promise them that their visit here will be earthquake-free.

Physics of a tsunami

With my parents still in New Zealand and on the coast in Greymouth (in the direct line for any tsunami emanating from the Honshu earthquake) I was reading around the speed of Tsunamis with some personal interest. However, I didn’t have to, since the Pacific Tsunami Warning Center [sic] has all the predicted “hit” times for the arrival of the wave or, more often, waves.

SEA LEVEL READINGS CONFIRM THAT A TSUNAMI HAS BEEN GENERATED WHICH COULD CAUSE WIDESPREAD DAMAGE. AUTHORITIES SHOULD TAKE APPROPRIATE ACTION IN RESPONSE TO THIS THREAT. THIS CENTER WILL CONTINUE TO MONITOR SEA LEVEL DATA TO DETERMINE THE EXTENT AND SEVERITY OF THE THREAT.

ESTIMATED INITIAL TSUNAMI WAVE ARRIVAL TIMES AT FORECAST POINTS WITHIN THE WARNING AND WATCH AREAS ARE GIVEN BELOW. ACTUAL ARRIVAL TIMES MAY DIFFER AND THE INITIAL WAVE MAY NOT BE THE LARGEST. A TSUNAMI IS A SERIES OF WAVES AND THE TIME BETWEEN SUCCESSIVE WAVES CAN BE FIVE MINUTES TO ONE HOUR.

Apologies for the SHOUTING, but this is obviously a rather important message.
UPDATE HERE and again HERE

And there is NZ on the list, with a predicted arrival time of 1930 GMT this evening. That’s 2130 SA time and 0830 tomorrow local time: over 12 hours after the earthquake hit. And that gives you an idea of how massive the scale of this is, because tsunami waves can top 900kph.

The wave speed is the square root of the product of the gravity constant (g) and water depth.

Tsunamis are normally produced by an earthquake or displacement of the seafloor due to plate shifts, etc. This produces a very large wave very rapidly, which then possesses significant energy.

The energy is distributed through the depth of the water initially, as it is displaced, but because of gravity and friction with the seabed, tends to decrease with increasing depth after a short while.
In deep water, the frictional affect on the wave speed is negligible near the surface. The more shallow the water (for instance as it approaches shore), the greater the affect of friction in slowing the mass of water above the seabed; most of the energy of the wave is transferred to the seabed, a small portion is lost to the atmosphere and in heating of the water.

Therefore, the more shallow the water, the slower the wave speed.

And with the Pacific generally being rather deep, the waves are travelling rather fast.

Thankfully, given the distances involved, that still gives my parents significant time to ensure their safety. Sadly, others nearer the epicentre, or without access to this information will probably not be so lucky.