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Eunoia
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--> Most recent Blog ![]() Comments Policy Impressum Maths trivia Search this site Sitemap YouTube Videos Eunoia, who is a grumpy, overeducated, facetious, multilingual ex-pat Scot, blatantly opinionated, old (1944-vintage), amateur cryptologist, computer consultant, atheist, flying instructor, bulldog-lover, Beetle-driver, textbook-writer, long-distance biker, geocacher and blogger living in the foothills south of the northern German plains. Not too shy to reveal his true name or even whereabouts, he blogs his opinions, and humour and rants irregularly. Stubbornly he clings to his beliefs, e.g. that Faith does not give answers, it only prevents you doing any goddamn questioning. You are as atheist as he is. When you understand why you don't believe in all the other gods, you will know why he does not believe in yours :-) Oh, and he also has a neat English Bulldog bitch 'Frieda'. And her big son 'Kosmo'.
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Friday, March 30, 2012
Dulce et decorum est?Apparently I've been upsetting people in the USA by pointing out the amoral nature of some of their military, be it pissing on enemy corpses or going on killing sprees of innocent women and children. War crimes. I'd like to know why Bush, Cheney, Rumford et al have not been tried for their war crimes? It's just the little guys (and the whistleblowers) who get busted, if at all. This led to a pub discussion of whether it is possible to separate patriotism from military context. The old lie Dulce et decorum est, pro Patria mori thus excluded. I was asked if I, as a pacifist, even had patriotic emotions? Sure. Just stand in the grandstand at Murrayfield rugby stadium before the match between the ancient foes Scotland vs. England and listen to our 40,000+ Scottish throats belting out Flower of Scotland at the top of our lungs. Tears come to my eyes :-) But I can feel patriotic about Great Britain too. I do enjoy the patriotic flag-waving and sing-along at the Last Night of the Proms. Joining in and belting out Rule Britannia, then Land of Hope and Glory (watch from 7:27 onwards). And so it pisses me off to see scenes like this, a screenshot from the traditional hymn Jerusalem (0:01 to 2:39) :- ![]() This woman has bought a Union flag* mounted upside down** on its pole. She wants the patriotic experience, but is too ignorant to buy a correct flag! I'll give her the benefit of the doubt and assume she is a foreigner. But what manufacturer is so ignorant as to make them upside-down like this? Made in China?? And the UK importer, is he too an ignorant foreigner? Jeebus wept! Then what about these people reading their programs because they don't know the words ? Booking weeks ahead, they go to participate in the most patriotic sing-along in the whole of GB and not make the effort to learn the words first ? Even foreigners can/should do that. Rant!Rave!! If my very English blogmate Four Dinners reads this, he'll have a hissy fit too!
Comments (3) : Wednesday, March 28, 2012
Accidents @ Home
Just a week ago we were talking about lab safety, when it occurred to me that many more accidents occur in traffic and even more at home. Of those domestic accidents here in Germany, over a half million happen to children. So it is the responsibility of parents to see what they can do to avoid them [the accidents, not the children, although . . . ;-)]. Modern ovens and espresso machines have a child-safety button that needs to be held down for long time (5 secs?) before the appliance will start. Modern irons turn themselves off if they have not been moved for a short(30 secs) while. Ceran induction heating areas only respond to the area being touched after the On-switch has been pressed twice, or turned then pressed in. If you have young children, you might want to upgrade your kitchen/electrical appliances to ones with these safety features. Even putting an acryl isolation plate on the door of an older oven will isolate it better, preventing burns. Bread slicers, irons, waffle-makers, frying-pots should all be stowed away out of sight in cupboards when not in use. Water-boilers (for making coffee/tea) and their associated cables should be positioned at the back of the kitchen surfaces, not near the front where a child (or even cat) can grab at a dangling cable. Most ovens have 4 heating areas on top, so just use the rear ones which a small child cannot reach. Turn the pan handles towards the back, not the front. The same applies to any steam-emitting spouts. Buy a grid that can be mounted on the front of the oven so that children cannot reach for pots and pans on the stove. Put one of those childproof temporary gates at the top of any stairs. Lock the medicine cupboard and store the key elsewhere. Put all cutlery away when not in use and keep the dishwasher closed. Fence in the garden pond. Thanks to DSH for the heads up on this list; it's not mine, I'm just passing their tips on in my own words for use by my blogreaders. Comments (2) : Monday, March 26, 2012
Star Light, Star bright
Supernova in M95 ! While I was looking at Mars, which is at its nearest currently and we had (rare) good seeing. Mars currently has a magnitude of -1. Much dimmer (9), but getting increasingly brighter over the next few months, is a new supernova II from a massive star in galaxy M95. You will need at least an 8 inch scope, magnification 120x used. ![]()
Star Light, Star bright,
Comments (1) : Sunday, March 25, 2012
Old Vinyl Meme, #8, 1977 :-)
Continuing on the weekly sundays' Old Vinyl Meme which I started last month, in which we show old LPs we own and link to a YouTube video from back then. You can read the meme rules here, feel free to join in, the more the merrier, as long as the vinyl LP is 30+ years old :-) ![]() This sunday's Old Vinyl LP is Bat out of Hell featuring Meat Loaf. The LP was published in 1977, first of a trilogy Bat Out of Hell, Bat Out of Hell II: Back Into Hell and Bat Out of Hell III: The Monster is Loose. From this LP I particularly like the track "Paradise by the Dashboard Light" co-starring the sexy Karla de Vito on this video. Bat Out of Hell has sold over 43 million copies worldwide, making it one of the highest selling albums of all time. Here is the video of my favourite (11 minute) track by the non-smiling Meat Loaf, the title number, Bat out of Hell in 1977. Karla de Vito accompanies. BTW, should you want to join this meme, the rules can be found here :- ... And thus do we learn of one another's eclectic music tastes :-) Do this meme! Comments (2) : Friday, March 23, 2012
Goodbye Doug Alder and thankyou
Ten years ago, when I started this blog on 1/1/2002, I was soon followed by Doug Alder from Trail, Canada, who started his blog on March 24th 2002. Just recently Doug mailed me that he will be giving up his blog tomorrow, on its 10th anniversary :-( He wrote "BTW I'm shutting my blog down permanently on the 24th - that makes 10 years and that's long enough, especially considering no one other than you and leftbanker reads it anymore." Well Doug, it's been a long haul this last decade. It has been a pleasure reading you and accompanying you along the ode[sic!] less taken. As you know, I've been having trouble accessing your site these past few weeks but I saw what may be your ultimate blogpost, appropriately enough a photo of a great sunset :-) I do however, find it ironic that the error message I get claims you are 'always online' :-( ![]() So this is just my way of saying thankyou for the 10 years of entertainment you have provided. Live long and prosper :-) Comments (5) : Wednesday, March 21, 2012
Lab Safety Anecdote - for Demeur
Richard Feynman used to tell this story about when he was working on the Manhatten Project, i.e. development of the first US nukes. The Manhatten Project was subject to top military secrecy, i.e. the grunts were only told the minimum they needed to know. Nowadays we KNOW that this leads to accidents and that best results are achieved if everyone involved has a deep understanding of what is going on. Fukushima being the case which proves my point. The scientists had enriched uranium in the form of a liquid and knew that multiple sub-critical masses were to be stored as far apart as possible. The grunts had been told to store the liquid in separate far-apart rooms, away from outside walls and away from the doors. But they had NOT been told about critical masses, nor about neutron flux, nor that wooden walls were transparent to neutrons. So this is how they stored the liquid in rooms A,B,C and D :-( ![]()
Far apart? Yup, thought the grunts, only accessible from separate corridors. But the neutrons from the radioactive liquid went straight through the wooden walls! Not only that, the grunts had tipped the liquid from the scientists' small bottles into large buckets (so that they would not have to carry them so often!). The buckets were borderline sub-critical! Not until a grunt reported that the buckets were still hot after several days, did a junior scientist (Feynman, back then) look to see what the problem was! OOPS!!! There are several Feynmann videos on YouTube, well worth watching. I still have a bound set of the Feynmann Lectures on Physics from my days at City University; the guy was a great teacher, not just a Nobel Prize winner ;-)
Comments (9) : Tuesday, March 20, 2012
Superluminal Neutrinos......are a thing of the future ;-) Think about it. Comments (2) : Monday, March 19, 2012
Freshman Chemistry Book Tip
My posts on chemistry led to someone's favourite aunt asking me "What could I buy my nephew who will be doing freshman chemistry beginning later this summer?". To which I replied : "Protective glasses, several pairs of rubber gloves and any book on his university's required reading list". But it turned out she didn't have that list and wanted a useful book as a surprise present. So I'm recommending to her my old favourite, Vogel's Quantitative Inorganic Analysis, as shown here. I used to have a first edition from 1937, but it got lost in a house move. So I got a used copy just for nostalgic reasons (I no longer do chemical analyses). It's the seventh edition, dating from 1996, revised and reworked by Professor Svehla (at Cork, Ireland), and now an even better lab manual :-) The ISBN number is 0-582-21866-7. Be interesting to get Carl's and Demeur's feedback on this tip and hear their tips. Comments (1) : Sunday, March 18, 2012
Old Vinyl Meme, #7, 1976 :-)
Continuing on the weekly sundays' Old Vinyl Meme which I started last month. You can read the meme rules here, feel free to join in, the more the merrier, as long as the vinyl LP is 30+ years old :-) ![]() This sunday's Old Vinyl LP is Cry Tough featuring Nils Lofgren mostly on guitar, but sometimes keyboards and anyway vocals. There is no date on the LP, but Wikipedia tells me it was published in 1976. Here is my favourite video by Lofgren Cry Tough, on slide guitar, in 1976. BTW, should you want to join this meme, the rules can be found here :- ... And thus do we learn of one another's eclectic music tastes :-) Do this meme! Comments (5) : Saturday, March 17, 2012
The wearing of the green ;-)
![]() Happy St.Patrick's Day. Enjoy yourselves! ;-) Comments (1) : Friday, March 16, 2012
Sheldon Cooper's alloys of Gallium ;-)
Sticking with the subject of chemistry, today I thought I'd tell you about several new alloys of Gallium (Ga) as attributed to Dr. Sheldon Cooper, B.S., M.S., M.A., Ph.D., Sc.D at Caltech. Now some of you may not remember your chemistry lessons from school, or have never seen research chemists at work (Hi, Carl), so for each of the elements mentioned in my blog today I'll link you to the excellent but simple educational videos on each of them featuring Nottingham university's professor Martyn Poliakoff, which are well worth watching. Here's their video about Gallium. Cooper's alloy #1 adds traces of Barium and Zink to the Gallium, the precise proportions being a Caltech trade secret (pat. pend). Here is the video on Barium which you may know from 'barium meal' used for its X-ray opacity when your doc is examining your guts :-) And here is their video on Zinc, which is often used to prevent rusting of iron. Besides, without traces of Zinc in your body, you would not be able to smell things. Cooper's alloy #2 is like #1, but uses Tin instead of Zinc. I guess this replacement idea came from England ;-) Here is the video on Tin; you'll all know Tin from the thin coating of tin on the inside of food cans. Cooper's alloy #3 adds traces of Boron, Arsenic and Indium to the Gallium. Here is the video on Boron; there is a small town called Boron in California, pop.2000. Here is the video on Arsenic, a poison famous in many detective stories (e.g. Arsenic and Old Lace). FWIW, the arsenic equivalents of pyrroles are called Arsoles; surprisingly or possibly not, Arsoles are not aromatic ;-) Here is the video on Indium, an element present in every LCD display because it conducts electricity AND is transparent to light :-) If you want your child to be the chemistry geek at parties, have them learn Tom Lehrer's periodic table song. I learned the Elements song off by heart back in 1960, but can no longer perform it. But even Harry Potter knows it off by heart. Theo Gray of Wolfram Research built a Periodic Table table. That's NOT a typo! You may be asking WHY these 3 alloys are attributed to Sheldon Cooper. Well, just consider the symbols for the elements in each alloy :-
Comments (4) : Wednesday, March 14, 2012
Nerdy place mat for budding scientists :-)
A friend of mine has a daughter now in secondary school who is turning out to be a science nerd like her dad. She particularly likes chemistry. But her parents don't let her read textbooks at the table at mealtimes lest they get messed up. To get around this I'm buying her this place-mat. Kilroy was here ;-) It is the periodic table of the elements, nicely colour coded. The metals have pale blue backgrounds, the non-metals pale yellow backgrounds and the semimetals/metalloids pale green. The symbols for the elements are colour coded too, gases in red, liquids in blue and solids in black [but for some reason I don't understand, Gallium is shown as a solid, even though it is (just) liquid at room temperature; hold it in your hand and it will melt!].
Top right in each box is the symbol for the element, here we see platinum(Pt) and gold(Au). Left thereof, we see the atomic weight (averaged over any isotopes) above the atomic number. At the bottom are the names of the elements (in german, this is a German periodic table). Between we see a child-friendly picture showing a common use of the element. The pictures are explained on the other side of the mat, indexed by atomic number up to 83 and to keep it simple, omitting the Lanthanoids. Radioactive elements are labelled by the usual schematic, the atomic weight is replaced by the count of the nucleons in the longest-living isotope, and the half-life of the longest-living isotope is shown in each box at lower right. As per usual convention, the Lanthanoids and the Actinoids are separated out and shown across the bottom of the place mat. This periodic table place mat cost me under 4 € , it is published (and copyright) by Ernst Klett Verlag GmbH, Stuttgart, 2008. The German version has ISBN 978-3-12-068580-7. They probably do an English version too, but I don't know the ISBN of that. Get one for yourselves for lunchtime learning! Comments (6) : Monday, March 12, 2012
Misuse of Mail :-(
I had thought that this was common knowledge, but since it appears not to be the case, I'll just repeat it for common edification. Email addresses are intended for point-to-point 1-1 communication. Sometimes they are used (IMHO misused) for broadcasting 1-N circulars. Some organisations have an opt-out policy, requiring you to say specifically that you do NOT want their broadcast infos. Some - with more respect for privacy - have an opt-in policy, omitting you from their broadsides (I use the word advisedly) UNLESS you say you specifically want to receive them. Some have no policy - or indeed inclusion/exclusion mechanism at all :-( Those who DO broadcast should address their mails to themselves and list the other recipients in the BCC field. BCC stands for Blind Carbon Copy. This implies that none of the recipients gets to see who all the other recipients are. This is called respect for the Privacy of others! What happens if you put your whole address book in the regular addressee field? Every recipient gets to see all addresses. Some of them will have their mailing SW set up to insert all those addresses into their own address book. Some of those computers may be infected with a virus, trojan etc; after all, not everyone is knowledgeable about computer risks. As a result, all those new addresses can get 'farmed' by professional spammers :-( This is how spams start and propagate :-( Don't do it!!! Especially not with commercial (for-profit) content, which includes (church) begging letters. The result is that many of your unwitting recipients will soon be receiving junk like this begging letter shown below :-( "From: Mrs.Mariama Ba : Beloved, Compliments of the day to you! By this e-mail, I do sincerely Apologize for my intrusion of your privates[sic!]. However, I have a serious concern with which I believe you might be of help and for this reason, I can not but reach out to someone - a fellow beloved. I am Mariama Ba, the mother to Gerard St. Germaine and Yvette St. Germaine who both died untimely in an Egypt Air crash 1999..." etc. etc ad nausam :-( I shall not mention the numerous - always embarrassing - examples of people (mistakenly) clicking 'Reply to All' instead of 'Reply' button. Recently even the German parliament had a flurry of these 'I am absent - bounce back' emails, caused by a secretary who should have known better. Don't do it either! Sunday, March 11, 2012
Old Vinyl Meme, #6, 1970 :-)
Continuing on the weekly sundays' Old Vinyl Meme which I started last month. You can read the meme rules here, feel free to join in, the more the merrier, as long as the vinyl LP is 30+ years old :-) ![]() This sunday's Old Vinyl LP is Band of Gypsys featuring Jimi Hendrix, Billy Cox and Buddy Miles on drums. There is no date on the LP, but Wikipedia tells me it was published in 1970, and so even qualifies as 40+ year Old Vinyl :-) I have a number of Hendrix LPs from 1967 onwards, Band of Gypsys was recorded live in 1970, just before his untimely death. All feature the unforgettable Jimi Hendrix, the most psychedelic guitar of the time. Here is my favourite video by Hendrix Star Spangled Banner @ Woodstock 1969, on YouTube, anacreontic indeed, 1969 at Woodstock. At the Isle of Wight festival he opened with God Save the Queen I remember, but I couldn't find it on YouTube just now to show to y'all :-( BTW, should you want to join this meme, the rules can be found here :- ... And thus do we learn of one another's eclectic music tastes :-) Do this meme! Comments (5) : Friday, March 9, 2012
A domino joke for the blind ;-)
T oday's shaggy dog story is specially written for Xtreme English, ex-teacher and editor extraordinaire. Once upon a time there was an English teacher who flipped out every time she saw one of her students - and anyone else for that matter - misuse an apostrophe. So to calm herself down, she sometimes went to the blind folk's home to play dominoes with the inhabitants there. The dominoes were embossed, of course, so that the blind folks could play too. Most of the blind folks had been tradespeople or shopkeepers, in fact as we see by the domino on the left, some of them were blind greengrocer's ;-) Comments (6) : Thursday, March 8, 2012
For Brutus is an honourable man. . . So are they all; all honourable men (Julius Caesar, Act 3, Scene 2). ![]() It is today that the German ex-President Wulff - who stepped down on 17th February after the district attorney applied to parliament to have his (Wulff's) immunity removed so that he (the DA) could pursue charges against him (Wulff) - gets his official military tattoo send-off. Until a new president (just a figurehead here) is elected on the 18th inst, the role is being formally fulfilled by his stand-in, Horst Seehofer :-( Yes, that Horst Seehofer, the one who produced a bastard daughter with one of the office staff whom he then dumped. Conservative family values, anyone? Wulff is shown above with Guttenberg, ex-defence minister, who resigned after it came out that his doctorate was plagiarised. The university withdrew said doctorate and Guttenberg fled to the US, much shamed.
Three German lessons for the day : "For Brutus is an honourable man... So are they all; all honourable men" (?)
Tuesday, March 6, 2012
Gardening Enigma Cribs
L ast month Brian (UK) asked me to write something about breaking the Enigma codes in WW2. For UK residents a visit to Bletchley Park (aka BP) is a (satur)day well spent and there is a lot of literature available, so it's difficult to write something new. But I shall try.
The Enigma is a cipher machine invented in the 1920s by Arthur Scherbius. There were commercial versions available before WW2, albeit when the Germans adopted it as their cipher machine they changed the rotor wiring. The Enigma has three rotors, a 'mirror' and a plugboard. Electrical signals from the keyboard go through the first rotor coming out at a different letter than they went in (depending on that rotor's wiring), ditto for the 2nd and 3rd rotor, are 'reflected' by the mirror (also coming out at a different letter than they went in) and then go back through the rotors again in the other direction. Then there is a monoalphabetic substitution by the plugboard before the resulting letter is lit up on a lampboard. After each letter the rightmost rotor rotates one position. After a full rotation of the rightmost rotor, a single fixed peg moves the centre rotor on by one position. After a full rotation of the centre rotor, a single fixed peg moves the left rotor on by one position. Thus the Enigma design achieved the maximum possible length for its keysteam (26*26*26=17576 characters) before repetition. No message was this long, and so the WW2 Germans thought the Enigma was undecipherable. If you read that description carefully you will have noticed three design flaws. Firstly, the use of a 'mirror' means that no plaintext letter can represent itself in the ciphertext. Secondly, the single fixed turnover once every 26 letters means that for 26 letter sequences all the other wiring is unchanged; it would have been a better design to have had 3 or 4 pegs whose positions could have been changed on a daily basis, IMHO this would have made the Enigma pretty much unbreakable. Thirdly, the plugboard only provides a (daily different) monoalphabetic substitution which can be stripped out with some effort (they had no computers back then). Later post-WW2 rotor machines such as the Swiss Nema had no plugboard. Now let's see how to exploit those design flaws using cribs. A 'crib' is a piece of plaintext which you expect to be hidden in the ciphertext somewhere. An often quoted example is the weather reports as sent at regular times each day.
'Weather report 0600...' is - in German, they spelled out the digits - 'Wetterberichtnullsechsnullnull", a crib longer than the 26 letters maximally useful.
For the purposes of this explanation I shall assume the 26 letter ciphertext is
'n h v p m n n r a o g q s y e v n d k k r f c g v'; I could have used anything else, it's not relevant here.
Lining them up, we see that indeed no letter represents itself, and so the plaintext could be in the ciphertext at this position. The next two positions would be permissible, then there are conflicts at E,S,N,N,N etc. Thus the design flaw of the mirror resulting in no letter representing itself enables us to reduce the candidate position from 26 to just 3. These 3 candidates could then be selected for menues for the Turing bombe, a WW2 top-secret combinational electromechanical engine (shades of steampunk) to further restrict permissible combinations until the correct solution appeared and was approved by a checking machine. The Turing exhibition at the HNF which Renke and I went to is currently displaying Turing bombe rotors, menues and a checking machine from BP. Obviously, the weather report alone would not suffice. The Brits at BP wanted as many cribs as possible, since the menues for the Turing bombe need a sequence of at least 7 or 8 letters with 1 or 2 loops in the menue. And thus they developed the technique of 'gardening' which means provoking the Germans to use a suspected specific plaintext. For example, the RAF would be sent to mine a previously unmined harbour, whereupon the harbourmaster would send a coded message to the German navy HQ saying "Mines in the harbour at Calais" (German plaintext: MineninHafenvonCalais); the crib. Sliding this crib back and forth along the ciphertext gives us just 4 candidate positions for the crib. Sometimes, the crib could be achieved by doing nothing! There was a German observer in North Africa who was left well alone by the Brits on the instruction of BP because on a daily basis he then transmitted 'KeinebesondereVorkommnisse' - 'Nothing special happened', a useful crib! Human errors. Like the German habit of signing their messages with their rank, thus 'LeutnantJaeger' was a useful crib. Most messages contained HH at the end, to short for a crib, but a few idiots spelled HH out as 'HeilHitler', also a useful crib for the codebreakers at BP :-) As a generalisation, I would say that most cryptographic breaks are attributable to human error on the part of the code users/makers. The Venona breakthough into Russian one-time-pads being the most famous unclassified, documented, example. Others are implied in the autobiography of East German spymaster Markus Wolf, who died in 2006. Comments (6) : Monday, March 5, 2012
Death Fader :-(
R
alph McQuarrie, the Hollywood designer who gave us
Darth Vader, Chewbacca, R2-D2 and E.T's starship, died on saturday, aged 82. May the Force be with him. Sunday, March 4, 2012
Old Vinyl Meme, #5, 1971 :-)
Continuing on the weekly sundays' ´Old Vinyl Meme which I started last month. You can read the meme rules here, feel free to join in, the more the merrier, as long as the vinyl LP is 30+ years old :-) ![]() This sunday's Old Vinyl LP is A Space In Time by Ten Years After. There is no date on the LP, but Wikipedia tells me it was published in 1971, and so even qualifies as 40+ year Old Vinyl :-) I have a number of their LPs from 1967 onwards, Ten Years After, Stonedhenge, Cricklewood Green, A Space in Time, and Alvin Lee and Company, all good, this just happens to be the most photogenic sleeve photo. All feature the great Alvin Lee, at that time, the fastest guitar in the west. Here is my favourite video of inter alia I'm going home, on YouTube, in a contemporary version, 1969 at Woodstock :-) BTW, should you want to join this meme, the rules can be found here :- ... And thus do we learn of one another's eclectic music tastes :-) Do this meme! Comments (3) : Saturday, March 3, 2012
R.I.P Bernd GehrkenSad phone call from Paul Gockel (Norton-Paule). All those years of smoking finally took Bernd Gehrken in his mid sixties :-( I only met him thrice (in 2000 in Worpswede, years later at a Münch meet in Beverungen and with Friedel Münch in Schotten), but he generously let me ride his Münch Mammut TTS-E (frame & motor number 188), the only time I've ridden one. Belated thanks again, Bernd; Rest In Peace. Friday, March 2, 2012
WWW : World Wide Wobbly
T he previous post was about Leap days as a method of keeping the calendars in sync with the seasons assuming a stable Earth. Today I want to talk about the ways in which this world wobbles. Let's start off with something seasonal as a first approximation. The Earth rotates around an axis running through from the geographic north pole to the geographic south pole. The magnetic poles are elsewhere and move around quite a bit annually, but that's a subject for another day. Slicing the Earth along the equator would give us a plane which is NOT parallel to the plane of the ecliptic, which is the plane of the Earth's orbit around the sun, but rather is at 23.44° to it. This is what gives us the seasons.
The extended axis between the geographic poles points to the celestial north pole, just 1° away from Polaris, the current pole star, which we amateur astronomers use to align our telescope mountings (so that a clockwork drive can drive the telescope in a single plane to track the stars for us). Notice I wrote "the current pole star" ? The Earth actually precesses like a spinning top pushed off axis. Think of it as if the axis line moves along the surface of a cone. The axis does not aim at a static point but describes a circle in the sky, taking 25,780 years to do so. So in 12,000 years time the pole star will be Vega, not Polaris. There being a star at/near the celestial pole is a fortunate exception nowadays, not the rule. But the Earth 'wobbles' even more. The pull of the Moon and the Sun cause the axis to nutate. This means that the axis does not draw a smooth circle in the sky; there is also a small sinusoidal nutation curve superimposed upon the circle. For the moment I will ignore the fact that the Moon is slowly pulling away from the Earth (due to conservation of momentum) as the Earth's rotation slows down due to the friction between the liquid core and the tectonic plates on the surface. Currently the moon is so near that we get full solar eclipses sometimes, but in the future we will only have the annular ones. I just mentioned the liquid core and the tectonic plates on the surface. The axis of rotation is NOT attached to the surface (or vice versa), and indeed the geographic poles move by upto 10 cms each day ! The pole spirals around inside a circle about 15 meters across. And all this has to be programmed into the GPS system for your smartphone/personal navi! World Wide Wobbly indeed! Comments (2) : |
23 Recent Writings
FWIW : 23 is the number of the Illuminati, folks ;-) Dulce et decorum est? Accidents @ Home Star Light, Star bright Old Vinyl Meme, #8, 1977 Goodbye Doug Alder Lab Safety Anecdote Superluminal Neutrinos... Freshman Chemistry Book Old Vinyl Meme, #7, 1976 The wearing of the green Alloys of Gallium ;-) Nerdy place mat :-) Misuse of Mail :-( Old Vinyl Meme, #6, 1970 Domino joke for the blind Brutus is an honourable.. Gardening Enigma Cribs Death Fader :-( Old Vinyl Meme, #5, 1971 R.I.P Bernd Gehrken World Wide Wobbly Leap Day Ruminations Trojan Ahoy Old Vinyl Meme, #4, 1970 Pardon? Orchid for Pharyngula Evolution : next step Archive 2012: Jan Feb Archive 2011: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Archive 2010: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Archive 2009: Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Archives 2002-2008 offline to save server file-space. Blogroll Ain Bulldog Blog Badtux... Balloon Juice Cheese Aisle Cop Car Cosmic Variance Curmudgeonly... Decrepit Old Fool Demeur Dependable Renegade Dr Grumpy Earth-Bound Misfit Fail Blog Finding life hard? Flight Level 390 Four Dinners Greg Laden HaggisChorizo Inspector Gadget Kees Kennis Making Light Mostly Cajun Not Always Right Observing Hermann One Good Move Pergelator Pharyngula Rants from t'Rookery Scary Duck Squatlo Rant Stupid Evil Bastard The Magistrate's Blog Too many tribbles Toxic Drums Xtreme English Yellowdog Grannie Link Disclaimer ENGLISH : I am not responsible for the contents or form of any external page to which this website links. I specifically do not adopt their content, nor do I make it mine. DEUTSCH : Für alle Seiten, die auf dieser Website verlinkt sind, möchte ich betonen, daß ich keinerlei Einfluß auf deren Gestaltung und Inhalte habe. Deshalb distanziere ich mich ausdrücklich von allen Inhalten aller gelinkten Seiten und mache mich ihrem Inhalt nicht zu eigen. This Blog's Status is
Blog Dewey Decimal Classification : 153FWIW, 153 is a triangular number, meaning that you can arrange 153 items into an equilateral triangle (with 17 items on a side). It is also one of the six known truncated triangular numbers, because 1 and 15 are triangular numbers as well. It is a hexagonal number, meaning that you can distribute 153 points evenly at the corners and along the sides of a hexagon. It is the smallest 3-narcissistic number. This means it’s the sum of the cubes of its digits. It is the sum of the first five positive factorials. Yup, this is a 153-type blog. QED ;-) Books I have written
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