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Astronomical split

A DARK corner of Feedback鈥檚 soul is, we confess, almost looking forward to a breakaway International Astronomical Union (Pluto-Xenaist) faction seeking to reverse the recent planetary demotions. One astronomer, for example, writes (on condition of anonymity due to the sensitivity of the issues): 鈥淧oor Pluto. One must truly sympathise. After all, it is at least an order of magnitude greater in mass than its new-found terminology-companion, Ceres鈥︹ He proposes therefore that the ex-planet of the God of the Underworld deserves a category of its own: giant dwarf planet. Or, anticipating reactions from people of different stature who do not embrace and reclaim the label of their oppression, mildly gravitationally challenged planet (MGCP), as distinct from the severely gravitationally challenged like Ceres.

Uncharted astrology

THEN there are the astrologers. Has nobody though of them? In the ancient system of knowledge they espouse, the positions of the planets affect, and have always affected, earthly affairs. When a planet appears or ceases to be, do they have to rewrite the whole past?

Philip Plait of couldn鈥檛 resist having fun with this on 14 August. He predictably garnered angry responses 鈥 including one making the startling revelation that a school of astrology has been 鈥減lotting鈥 an entirely unobserved 鈥減lanet鈥 that it calls Transpluto, just in case.

鈥淎 鈥渄esk tidy clock鈥 from Office Works bears the instructions: 鈥淪etting up SNOOZE makes time increase or subtract by pressing UP or DOWN鈥. Matt Abrey promises to use this powerful function carefully鈥

Preparing for an onslaught of actual post-Pluto planets, declared: 鈥淭he teaching in western astrology is that when a new planet is discovered and named, the archetype鈥 is at that point available to all of humanity鈥 an abundance of new inner energies available to the human race.鈥 Their influences may be revealed by a fetching picture of Xena, the fictitious feisty warrior princess who supplied the nickname for the object 2003 UB313 that provoked the current fuss by being bigger than Pluto.

So how do they deal with the unexpected deplanetisation? 鈥淣ot to worry. This changes nothing鈥 Pluto remains a full planet for astrologers.鈥 But鈥 wouldn鈥檛 astrologers differ on this question, depending on what was in opposition to Xena when they were born? Besides, shouldn鈥檛 they have known the outcome of the International Astronomical Union meeting in advance?

Pathologically usual units

IN A more recherch茅 corner of astronomy, Bernard Peek recalls a colleague coming up with what we might call a system of pathologically usual units. Unusual units seem to originate with journalists and copywriters stretching out for a helpful comparison 鈥 and missing by a fingernail (0.2 millimetres). For this astrophysicist, however, as for many of the mathematically inclined, the motivation is a simple hatred of tedious arithmetic.

Peek鈥檚 colleague chose units so that the speed of light and the gravitational constant are both 1. From this you can derive units of length 鈥 a light nanosecond is about a foot (0.3 metres). And because the gravitational constant defines how fast masses accelerate toward each other, working backward from a value of 1 defines a unit of mass that turns out to be 1 Jupiter or, as Peek notes, close enough to it for astronomy.

Et voil脿 鈥 the FJN (foot, Jupiter, nanosecond) system. So much less parochial than using metres based on the circumference of the Earth.

CO2 is good for the planet

PUZZLED as to why so many interpret the effects of CO2 differently to the reality-based community, Glyn Hughes went searching. And he found an explanation. To the US government 鈥 or at least to sections of its Environmental Protection Agency 鈥 CO2 is not carbon dioxide. A guide to pollution calculations (published for example at ) defines CO2 as 鈥渃oncentration of oxygen鈥. So if CO2 levels are rising, it needn鈥檛 have anything to do with any pesky greenhouse gas. And as fans of alternative therapies know, since oxygen is vital, more of it must be better.

Where dogs may safely play

A PHOTO sent by Mark Shuttleworth from the grounds of a west of England hospital declares: 鈥淲ALKING DOGS playing games or other recreational activities are not allowed on this field鈥.

Are running dogs free to play as the whim takes them 鈥 or only literate running dogs? Or is 鈥渨alking dogs鈥 a euphemism for an activity that would preclude the other uses? We think we鈥檇 rather not get to the bottom of this.

Tolerance conundrum

FINALLY, we won鈥檛 say where Richard Mallett works, but a new electronic product he is working on needs a 鈥渮ero-ohm resistor鈥 鈥 simply a bit of plain wire packaged like an actual resistor for ease of robotic insertion into a circuit board.

The purchasing department came back to say they couldn鈥檛 get components with a resistance of zero ohms plus or minus 1 per cent tolerance 鈥 would 5 per cent tolerance do? They鈥檙e as puzzled as Mallett as to how significant 5 per cent of zero can be.

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