As the U.S. declines as a world superpower, to make way for China, we can still all derive some comfort from its homely wisdom. 

"Aim towards the Enemy." - Instruction printed on U.S. Army Rocket Launcher

"When the pin is pulled, Mr. Grenade is not our friend." - U.S.M.C. Training Bulletin

"Cluster bombing from B-52s is very, very accurate. The bombs are guaranteed to always hit the ground." - U.S.A.F. Literature.

"If the enemy is in range, so are you." - Infantryman's Journal

"A slipping trigger gear could let your M203 grenade launcher fire when you least expect it. That would make you quite unpopular in what's left of your unit." - Army's Magazine of Preventive Maintenance

"It is generally inadvisable to eject directly over the area you just bombed." - U.S. Air Force Manual

"Try to look unimportant; they may be low on ammo." - Infantryman's Journal

"Tracers work both ways." - U.S. Army Ordnance Manual

"Five-second fuses only last three seconds." - Infantryman's Journal

"Bravery is being the only one who knows you're afraid." - David Hackworth

"If your attack is going too well, you're walking into an ambush." - Infantryman's Journal

"No combat-ready unit has ever passed inspection."

"Any ship can be a minesweeper… once." - Anon Naval brass

"Never tell the Platoon Sergeant you have nothing to do." - Unknown Marine Recruit

"Don't draw fire; it irritates the people around you." - Your Buddies

"If you see a bomb technician running, try to keep up with him."

Is there somebody you really hate? Do you loathe them beyond all reason? Send them the perfect present.

The incomparable Hunter Gracchus perform at the Centre for Contemporary Arts, Sauchiehall Street, Glasgow on Saturday, 13th June, courtesy of Psykick Dancehall Recordings.

If this is the Standard version of English, what's the bad stuff like? Although this is an understandable problem with the apostrophe, we think a major newspaper might know the difference. Watch out for a future post on the reason for  the "its" and "it's"  discrepancy.

In fact, do you think it matters? Log on and blow your horn about it.

(Legal disclaimer to avoid massive suing of Ludamus: the newspaper may well claim that this notice is nothing do do with them, and that it was written by an individual vendor. The two notices look identical, suggesting central printing, but it may not have been by the august newspaper itself. On the other hand, wouldn't it be nice if they took steps to make sure that it was right?)

Ludamus heard this one recently at an Open University staff development meeting, which means that it must have some deep intellectual content.

Here's an interesting snippet. Funeral directors in the UK can belong to a professional organisation called the National Association of Funeral Directors, whose acronym is NAFD. Very appropriate.

PS the first line on the site is "Why choose a NAFD member?"

If you're in Leeds at the relevant time, you could take an official test supervised by a qualified psychologist. If you're not in Leeds at the lucky time, then you can apply to sit it somewhere more sensible. (By the way, did you know that inhabitants of Leeds are called Leodensians?)

Continuing the thoughts of geek speak that were kicked off with the micro-fortnight, do you know the definition of a milliHelen?

One milliHelen is the exact amount of beauty required to launch one ship.

We may think that relativity is abstract and far removed from everyday life and the "real" world. Time, for instance, is said to run differently depending on our speeds or environments, but is it so tiny as not to be noticable in everyday life?

It is relevant, and it is noticeable. Global positioning systems, which we use in cars, planes and ships, depend on measuring the time radio waves take to reach us from a satellite of known position; this enables the receiver, which measures the travel time of the radio signal, to work out the distance from the satellite. Once four satellites have been measured, we can find our position.

Now if the satellite clocks were to run at a slightly wrong speed, say losing 2 nanoseconds a day (that's 2 billionths of a second per day), then the satellites would appear to be 60cm further away each day, and we would soon have a build-up of error.

The times on the satellite clocks thus have to very accurate indeed,and any small effects (such as those due to relativity) can have a real effect on the navigation abilities of GPS systems.

There are in fact two relativistic effects: the speed of the satellite relative to the ground slows its clock by 7 microseconds per day (that's 7000 nanoseconds per day); on the other hand, the weaker gravitational field up at the satellite orbit means that clocks run faster by 45 microseconds per day. The net effect is therefore that the clocks on the satellites run faster by (45-7), or 38 microseconds per day. That's 38000 nanoseconds, or a cumulative error of over 11 kilometres per day! That's a large error for such a non-real, airy-fairy theory that isn't supposed to affect real life.

Cheer up. The people who run the systems know about this, and build in corrections so that you won't try to drive the car into one of the craters on the Moon.

If you're a fully-grown, paid-up geek, then you can use the official unit of geek time, the micro-fortnight.

If you work it out, one micro-fortnight is a millionth of 14 days, or 14*24*60*60/1000000 seconds, which comes out to 1.2096 sec.

Not quite a second, but close enough for saying things such as:"I'll only be a couple of micro-fortnights".