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Friday, October 30, 2015
Hitler's houseust 50 kms from Passau, upstream along the river Inn, is the nondescript Austrian town of Braunau-on-Inn. Its claim to fame is that it is the birthplace of Adolf Hitler. The town council is not particularly proud of this fact, so they display no signs etc telling you how to find the house (but thanks, Wikipedia), but it's the one where they regularly (but badly) try to remove all the fans' and haters' graffiti ;-)
Although no signs indicate that this house was the birthplace of Adolf Hitler, there is a plaque outside which translates as " For peace, freedom and democracy! Never again fascism! Millions of dead admonish!"
Near the other end of his existence, Hitler lived on the mountain at Obersalzberg where - playing safe against Allied bombers - they built a huge bunker for him and his staff. Frank took this photo of the bunker entrance as it is today, part of a hotel complex, but open to tourists.
My mood improved, as I spent the rest of the day riding through the rolling hills of the Bavarian Woods, warm and the sun had come out :-)
I even discovered that there is a village called Prague in Germany too ;-)
To be continued . . .
Wednesday, October 28, 2015
Passauack to the story of our 2015 motorcycle tour.
Freyung in Bavaria was our base for nights 10 and 11 of our motorcycle trip because Frank had spent pleasant childhood vacations there. While Frank rode 500km to visit friends Tatjana and Ralf, I took a lazy day, only visiting nearby Passau etc (<200 kms).
First off, I took a riverboat ride on the 3 rivers that meet in Passau. Besides the day-boats, there were plenty of hotel boats going from the North Sea to the Black Sea and making a day's stopover in Passau. The boat shown below is a river restaurant boat, spectacularly lit at night.
The small white tower projecting into the Danube river (see below) was the 16th century customs post where passing boats had to pay their dues. It seems defence was a larger issue than having windows [sic!];-)
The green (copper) topped towers shown in the photo below belong to St. Stephan's cathedral. This is home to the largest church organ in the world (about 17,700 pipes) and I had come to hear an organ concert :-)
So had about 2000 other people, who were also admiring the baroque interior of the cathedral. I must admit, the OTC does pomp rather well.
If you crane your neck, you get a good view of the beautiful paintings on the ceiling of the cathedral. Camera focus could have been better :-(
But punctually there was a hush and after a compulsory RC prayer (the OTC forcing itself on us non-believers) we listened in rapture for an hour to the thundering music from the great organ(s). There are 5 organs scattered throughout the cathedral, all integrated to be playable from any of 6 consoles. Each console has (afaik) 5 manuals and one pedal-board, 233 registers ( with full 233 stops) and 17,774 pipes. BTW, the organ at West Point chapel has over 23,500 pipes but only one console.
Here is a video of an organist playing J.S. Bach's Toccata and Fugue in D minor.
And here is another You-Tube video of the inside of the cathedral during some rather free improvisation on the organ. Enjoy!
I have also heard the smaller but oldest (1435) organ in the whole world, one manual, 2 stops, in the Fortress Cathedral in Sion, Switzerland. Passau is much better as expected :-)
Tip for lunch : try the "Holy Ghost" (Heiliggeist) inn. Olde-worlde cellar atmosphere and great food there too!
To be continued . . .
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Monday, October 26, 2015
Chaos of the clocks :-(id you Europeans remember to put your clocks back one hour yesterday (onto winter time)?
There is no worldwide uniform rule as to when the clocks change from summer to winter time; at least the EU synchronised themselves. Other countries did away with changing their clocks at all : Iceland, Russia, Asia (apart from Mongolia), most of Africa and most of South America.
Most of the USA, Canada, Cuba, Bahamas and Mexico will change over on November 1st (first sunday in November). But there are exceptions : Arizona, Hawaii, parts of Indiana, Puerto Rico, Guam, Virgin Islands and American Samoa don't change their clocks at all. Turkey doesn't change it's clocks until November 8th.
And there are some really weird cases too : On the east coast of Australia, right on the border between New South Wales and Queensland, is Coolangatta (called Tweed Heads in NSW). New South Wales uses summertime but Coolangatta does not. This also means that you can experience two fireworks displays within one hour on New Year's Eve ;-) In Mexico, some towns near the US border follow the US rules, others use a different date; whatever is best for business it seems!
The Vatican and IS of course are still several centuries behind the times.
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Friday, October 23, 2015
Cesky´ Krumlovack to the story of our 2015 motorcycle tour.
After an inferior stay in Brno we rode next day to see Cesky´ Krumlov, a picturesque historical tourist town in a bend of the river Moldau (CZ).
We parked behind the castle (top centre of the map) and entered the lower town below the castle bridges. The two parts of the hilltop castle are connected via passage-buildings built on bridges across the upper gorge. The church is at the eastern end of the ridge, next to the castle.
We crossed a footbridge downstream of the weir across the Moldau.
This is one of the beautifully painted buildings in the lower town in the loop of the river Moldau. Many are now shops, cafe´s or restaurants.
There are many narrow alleys through which to wander (=tourist traps ;-) and even the old mill has been turned into a music bar!
There are many riverside bars, cafe´s and restaurants. We chose one at random for lunch.
Waiting for our meal, we watched the swallows & swifts hunting for low-flying insects just above the water. So "swift" that they were hard to photograph . . .
After lunch we took a forest road to get to Freying in Bavaria, but had to wait awhile until the tree-fellers cleared the road for us :-)
To be continued . . .
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Wednesday, October 21, 2015
Back to the Future II Dayack in 1989 Zemeckis released the second movie in his Back-to-the future trilogy wherein Marty McFly and his friend Dr. Emmett "Doc" Brown travel to 2015 in a time-travelling De Lorean. The date shown on the time-machine's instrument panel was October 21, 2015. Today!
It is very difficult to predict the future. I know because I am on public record of having done so back in a comparable 1985, with mediocre results :-(
So let us see what technologies the movie got right and what didn't happen :-
Right : Wall-mounted flat-panel TVs, TVs with multichannel displays, video-chats, head-mounted displays (=Glass), ubiquitous cameras, 3-D movies.
Wrong : Hoverboards, flying cars, powered self-lacing shoes to name but the obvious three.
Now that was predicting just 30 years into the future when it was scripted. Let's take a stab at predicting technology 30 years into our future, 2045.
Predictions for 2045 : No hoverboards, but electric bicycles ubiquitous. No flying cars, but self-driving and electric cars. Mankind (probably Chinese) on Mars. Alien civilisations found in our galaxy, but no contact (yet!) due to lightspeed limitatilaif off next year and the factory closons. Dark matter found (and, sadly, weaponised). No portals, no teleportation, no time-travel. No superhuman AI. 3-D surround vision mobile phones causing Matrix-like addiction problems.
FWIW : the ONE thing that Nostradamus got absolutely right - despite all those gibberish predictive(?) 4-liners - was his recipe for cherry jam ;-)
What are YOUR predictions ? Even for 5 years you need 2020 vision ;-)
BTW, I've heard that Universal Studios plan to re-release the trilogy alongside new features on DVD and Blu-Ray on today, October 21, 2015, coinciding with "Back to the Future Day". The new set will include a featurette called "Doc Brown Saves the World", where Lloyd, reprising his role as Doc Brown, explains the reasons for the differences between the future of 2015 as depicted in Back to the Future Part II and in real life. Looking forward(sic!) to that :-)
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Monday, October 19, 2015
Kunovice Aircraft Museumay nine had us heading for Brno in the Czeck Republic. Yellowdog Grannie who lives in West, Texas, told me they were having visitors that very day from Kunovice (CZ). So I said we would be riding through Kunovice to see the aircraft museum and I sent her a bunch of Kunovice photos. Here are the others, all of the Kunovice Aircraft Museum. Well it's more of an Aircraft boneyard really, only 2 restored to flying condition, the rest just dumped where the Soviets left them years ago, when they left the country :-(
The first plane I recognised was a MiG 15, the headlight in the air-intake identifies it as a MiG15bis model. It was a single seat subsonic (M0.92) fighter designed to shoot down B29s. Its US counterpart in the Korean war (what the Koreans call "the American war") was the F86 Sabre, both derived from a German WW2 prototype. The MiG 17 was just a Mig 15 with an afterburner. BTW, North Korea still has MiG15s on active duty ;-)
Next to it was a Sukhoi SU-7, a Mach 2 fighter-bomber (the fighter version never saw combat) which was the main Soviet ground-attack aircraft of the 1960s. Downside of this design was the length of runway needed and the miserably short combat radius. It could however carry a nuke :-(
The Aero Ae45 was the first (1951-1963) Czech-built post-WW2 twin piston-engined civil utility aircraft used for liason flights.
I couldn't identify this one. I took it be a Ilyushin IL-14, a copy of a Douglas with a tricycle undercarriage. Looks like the bomb-aimer's cabin had been added to the nose as an afterthought ;-) Can any blogreader name it?
I climbed inside the cockpit of a 30 passenger turboprop twin. The avionics are western-style and appear to be from the early 1980s. Just LOVE those cockpit ceiling ventilators, they'd probably hack your fingers off if you fumbled for the overhead switches in turbulence ;-)
This is a WW2-era radial-engined trainer, local equivalent of an AT6 Texan.
Finally, one which had been restored to a flying condition, an Aero L-29 Delfín, Czechoslovakia's first locally designed and built jet aircraft. It was the standard jet trainer for the Warsaw Pact in the 1960s. It was slow (350 knots) but docile and easy to maintain. There was a privately-owned one at the airfield (EDLP) where I used to instruct a decade ago. In 2008, tuned versions were the Reno race winner and second place, at over 500 mph.
To be continued . . .
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Friday, October 16, 2015
Banska´ Bystricaay eight of our motorcycle trip began with rain :-( Orographic rain in the Lower Tatra hills, but it was coming down in sheets :-( So, instead of taking the longer and picturesque route through the forest of the Nizke Tatry National Park as planned, we chickened out and took the shorter main road along the south side of the park. It cheered us up when we discovered the road number ; we were riding Route 66 (albeit in Slovakia) :-)
We were heading for historical Banska´ Bystrica, the centre of the ill-fated Slavik uprising against the Nazis in 1944. Biking is often a history lesson :-)
And so, after three miserable hours, we came out of the hills at Banska´ Bystrica, a popular tourist spa town, which was our next planned hotel stop. There the rain was just stopping and the sun coming out :-)
Big bikes attracted the local youth; here's the smallest wannabee biker trying Frank's bike for size. He panicked when Frank started the engine though ;-)
The central square in Banska´ Bystrica is dominated by the soviet-style war memorial, a black obelisk. There are plenty of cafe´s and restaurants there too. Slowakian waitresses are selected for their beauty it seems. Sylph like figures, photo-model styled. 50 kg at most; jeans like they were sprayed on. Think Johnny Depp's daughter Lily Rose (16) or Sophia Thomalla (26). Wow!
The architecture of the older churches showed a dual role as places of defence. That's an archers' gallery on the left there, opposite the art gallery!
The central fountain is more modern, almost ugly :-( The houses around the plaza were well restored after WW2, restaurants are often in the cellars.
Talking of restaurants, we'd try the local Slowakian dishes we decided. but were unable to read the menu so pointed at the median price...
And this what we got, Slowakian specialities, a bean stew with lots of sausage in it and something like mac & cheese with chopped ham in it. Both delicious!
After lunch we visited the Museum of the Slovak National Uprising. Outside there is this Russian IL-2 plane which seemed to be a 1:1 copy of a Douglas DC3, except that the Russians seemed to need a crew of six(!) to fly it :-(
Apropos airplanes, the following day we'd planned to visit the aircraft museum in Kunovice(CZ); I'll cover that in a separate blogpost...
To be continued . . .
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Wednesday, October 14, 2015
Hungary : the Aggtelek national parkay seven of our motorcycle trip and we decided to tour the Lower Tatra hills and visit the Aggtelek national park in Hungary. On the way south we came across some spectacular crumbling castle ruins...
The border to Hungary is a Schengen open border, just the country's sign and the standard speed-limit reminder, although the minor roads are empty.
We had come to visit the Aggtelek National Park (caves in karst hills), vast (24 km long) stalactite caverns of the Baradla-Domica cave system.
The place was chock-a-block with cars and RVs with long queues for the 7km guided tours through the caves so we continued our motorcycle tour instead, enjoying the hilly and curving nature of the roads through the karst.
The villages there are small, neat and clean : no Roma/Sinti slums there!
To be continued . . .
Tuesday, October 13, 2015
Ada Lovelace Dayctober 13th was arbitrarily chosen as Ada Lovelace day to have less conflicts with other pseudo-celebrations. It's not even her birthday.
There is a programming language ADA named after her.
There is also an AI (Artificial Intelligence) test named after her because she firmly believed that only if computers could originate things (creativity) could they be believed to have minds and that this is thus a better test than the Turing-Test. Here is a PDF of the paper proposing the Lovelace Test. And here is Riedl's V2.0 thereof.
The HNF has an Ada exhibition, this year being her 200th anniversary. But since they didn't have enough material, they widened the exhibition's scope to cover early famous women in computer science.
This includes Grace Hopper whom I had the honour to meet once. She established COBOL (despite a team-member carving a tombstone for COBOL before the project even finished ;-) and wrote the US Navy test suite for COBOL compilers. I and several co-workers wrote a COBOL compiler (in assembler) for the Telefunken TR86 and used her test suite, hence the connection. This was back in 1969/1970. Somewhere, I still have the 30cm of wire (=1 nanosecond at lightspeed) which she often distributed :-)
The HNF is good at displaying hardware but has no talent for displaying software. To illustrate a COBOL compiler they just displayed a magnetic tape reel which they said contained a compiler :-( Jesus wept :-(
Monday, October 12, 2015
Narodny Park, Poloniny, NE of Snina (SK)n the very northeast corner of Slowakia is a National Park where - we had been told - there was a chance of seeing some wild animals: bears, wolves and eagles. So we went exploring there on the sixth day of our motorcycle tour, but only got to see an eagle.
The park is heavily wooded - the trees come right down to the (single) road and the foliage is so dense that we would not have seen a bear even if it had been standing a mere 3 or 4 yards from us :-( Quiet hikers might have more luck; the sound of our bikes probably scared the animals all off :-(
The park borders on Poland and the Ukraine so there is no through road, the only road is a dead end. Literally : it ends in a graveyard!
The graveyard belongs to the old wooden church of St.Michael the Archangel which dates from the end of the 17th century. Looks a bit like a Stavskirk(N).
These churches are called "tserkvas", they occur in all 3 countries in this area. They have beautiful iconic decorations inside, mostly in a vivid red.
The 20th/21st century part of the graveyard had - like many other graveyards in Slovakia - fresh flowers on EVERY grave it seemed. What a religious people we thought, in Germany there will usually only be fresh flowers covering the graves of the recently buried.
However, upon closer inspection, the flowers are not fresh at all : they are plastic! A really practical approach to eternity, I joked.
After leaving the National Park we headed WSW to Mlynky, the vowelless Low Tatra village to be our hotel home for the next 2 nights. On the way there we rode through Slovakia's poorest region it seems. Ribbon villages (a row of houses on each side of the only road) began and ended with Roma slums & ghettos. The photo below shows one of the better Roma houses, but with a collapsing roof, (occupied by Roma after the local owners fled?). Many hovels are just breeze-blocks piled amateurly on top of one another, almost no mortar. There are sewage pipes, electricity and a manual village water pump provided by the government in the interest of public health.
In our hotel in Mlynky we met a young student who is writing her master's thesis about the Roma poverty in Slowakia. She told me there are about a half a million living there. Lots of children, many do not attend a school (because neither did their parents). 90% unemployment. The families live off social security (which seems not to cover the cost of condoms!). High crime-rate.
A consequence of this regional poverty is that there are not many cars and thus petrol stations are far apart (like 60 miles, where I'm more used to 5 to 10 at home). Twice we had to divert from the planned route just to find a refuelling station so that I could refill my small tank :-(
All in all, the poverty here made us grateful for our relative prosperity.
To be continued . . .
Saturday, October 10, 2015
The High Tatra (SK, PL and UA), continueday five of our motorcycle trip took us back up into the mountains, touring the High Tatra, hoping to get to the top on this clear day.
We wanted to see if we could get at a ticket on the cable car to the top of the highest peak.
In the photo above you can JUST see the top station and observatory glinting in the sunlight. In the photo below - with my camera zoomed 30* to the max, you can see more details, albeit 5 or 6 kms away.
HUGH queue for the cable car though. At 9:30 booked out until 16:30 :-( No chance, all booked out. So we decided to pop over into Poland and see what southern Poland looks like.
Very agricultural, little mechanisation, and 15°C colder because the High Tatra acts as a weather divide. The Polish side was cold, cloudy and rainy, so we returned to the sunny, warm, Slovakian side after this short photo-stop.
Back in the warm weather we headed for our overnight hotel in Snina. Since we got there early, we just dropped off our luggage and went to take a look at the Ukraine(UA). A non-Shengen real border, like during the cold war.
Turned out Frank didn't have his passport with him, just an ID-card, insufficient for the Ukraine to allow him entry.
So he stayed there while I went to at least get a Ukraine stamp in my passport. I gave him my camera as I didn't want all my photos
and the camera to be confiscated (for possible espionage?)
and my pack of used playing cards. An old cold war crypto-trick : the card sequence in a shuffled pack has an entropy of some 225 bits and so can be used
as a fairly secure crypto-key. If the border guards insist on seeing the pack, you just "accidentally" drop it, destroying the sequence :-)
But after about a half-hour of burocratic rigmarole - not aided by my lousy Russian and non-existant Slovakei and Ukrainian - I finally emerged back into Slovakia triumphantly with Ukrainian entry and exit stamps in my passport :-)
Meanwhile, the border guards were getting itchy and were remonstrating with Frank for taking photos of the border post, so we turned back & left :-(
To be continued . . .
Thursday, October 8, 2015
Finally : The High Tatra (SK)ay four of our motorcycle trip and we finally crossed into Slovakia (where the roads promptly deteriorated).
We took the minor (but asphalted) country roads; once out of the woods we could see the High Tatra mountains ahead. Rising directly out of the plain, they offer a splendid panorama, getting clearer as we got closer :-
Although we tried to stay on small mountain roads, sometimes we had to take a larger, wider, road (which had been smoothed out in some places, where the tourist traffic flows). Mostly, the minor roads were pretty empty.
After a pleasant day just riding, we turned south, descending to our hotel in Poprad, always mindful of unexpected cross traffic ;-)
No barriers, no flashing lights, just the blare of the train's horn :-(
To be continued . . .
Tuesday, October 6, 2015
Olomouc (CZ)he road through the Czech Republic from Kutna´ Hora to Olomouc is boringly straight. We bikers prefer twisty, hilly roads. So we were glad to arrive at the booked hotel, a Best Western. Or rather a less-than-good Western. Why? 1) Outside the city limits, 2) although each room had a thermostat, none had air-conditioning, 3) No refrigerator/mini-bar in the rooms, 4) dining room a 300 yard walk from the rest of the hotel, 5) no garage parking 6) disappointing breakfast, etc etc.
So next morning (day 4 of our trip) we made an early start and began by taking a look at the city centre of Olomouc, the historical capital city of Moravia. In particular, we wanted to see Horní námestí, the largest square in Olomouc, which I'm showing you in the photos below.
The square is dominated by the Holy Trinity Column, the biggest Baroque sculptural group in the Czech Republic.
But the other statues are good too, and the period houses are well restored.
The 15th century town hall has been beautifully renovated too :-
The town hall is home to a splendid huge astronomical clock in a rare Socialist Realist style (proletariat instead of saints). The original 15th-century clock was wantonly destroyed at the end of WW2 :-(
I quite liked this fountain too with its brass turtle...
This reminded me so much of Terry Pratchett's Great A'tuin, the turtle bearing four elephants on its back who carry the Discworld®, that I took the opportunity of riding on the back of a brass turtle. De Chelonian Mobile ;-)
Not as bad as this woman in Florida who rode a live loggerhead sea turtle, an endangered species, and who can expect a hefty fine or even jail! :-(
To be continued . . .
Monday, October 5, 2015
Selfie shirt ;-)ad a neat idea for a T-Shirt logo last thursday and made myself this T-Shirt (in German, because that's where I live).
People take a few seconds to decipher the mirror-image letters, digest the content, and then give it a thumbs-up :-)
But one guy at the pub on friday evening proudly demonstrated that HIS mobile phone is clever enough to flip images taken with the user-side camera, thus rendering the T-shirt logo legible. My neat idea has been overtaken by technology :-(
Saturday, October 3, 2015
Sedlec Ossuary in Kutna´ Hora (CZ)ur second stop on the 3rd day of our motorcycle tour was at the Sedlec Ossuary in Kutna´ Hora (Czech Republic). This Ossuary is in the crypt of a Catholic church and is decorated with the bones of 40-70,000 bodies. It is one of only twelve World Heritage Sites in the Czech Republic and worth seeing when passing through.
Under the arches to the left and right of the descending entrance stairs are four huge stacks of bones, mostly skulls and femurs (thigh-bones).
Zooming out, you can see the sheer size (over 12 feet) of these piles of bones.
Most of the decoration is in the style of a skull and a single thighbone. Not sure if the inspiration for this design was a single-legged pirate or an apprentice freemason ;-)
One of the more spectacular display pieces is the coat of arms of the noble who paid for the redecoration. It is placed beneath an arch of the more traditional freemasons' skull and crossbones and a chain of skulls. BTW, many of the skulls have head-damage, from a sword or a mace it seems, implying they belonged to someone who died in battle.
Most spectacular of all is the central chandelier, said to contain at least one of each bone in the human body, and made from several skeletons. There is a candle on each of the skulls in the chandelier. The ceiling above the chandelier holds several chains of skulls and crossbones; think a Xmas-cum-Halloween decoration. But it doesn't feel at all macabre!
How did this ossuary come to be? My version differs only slightly from the propaganda version of the OTC® (One True Church). In 1278 Henry of Sedlec was sent on a crusade to Jerusalem. He returned piously with a bucket of soil from Golgotha, so that he could be buried in Holy Ground. After his burial the OTC® redistributed the soil around the graveyard and charged extra fees to all the people who also wanted to be buried in Holy Ground (but without the bother of actually going to Golgotha). And the money flowed in . . .
By 1511 (after the Hussite wars and the Black Death) the graveyard was overflowing, so a half-blind monk was assigned the task of exhuming the skeletons, cleaning the bones (in holy water?) and so the OTC® could reuse the graveyard and the income stream continued. Plus of course, the OTC® could now charge an entrance fee for people wishing to see the ossuary. It still does : we payed about 3€ each.
In 1870 the owners (the Schwarzenberg nobles) charged Franz Lint, sycophantic woodcarver, with rearranging the ossuary to the design we see today. It is the Schwarzenberg coat of arms you see in my photo above.
In the pub across the road for lunch, there were some american bible students, one wearing a skull and crossbones T-shirt. I asked him if he'd worn it especially to visit the ossuary. He laughed and replied that no, it was his last clean shirt. Off the cuff, I quoted Revelations 22:14 at him "Blessed is he who washeth his robes" which caused even more merriment ;-)
To be continued . . .
Thursday, October 1, 2015
What is it like to be a bat?hilosophy class 314 : we have to read and criticise Thomas Nagel's 1974 paper What is it like to be a bat?. Philosophers often pose questions like "How many angels can dance on the head of a pin?", useless in everyday life, not susceptible to empirical proof, then talk about something else. Which is what Nagel did. He waffled about consciousness instead.
Nagel doesn't even try to answer the question, claiming instead that the bat's consciousness is inaccessible to us. And this is supposedly the most widely cited and influential thought experiment about consciousness? Rather disappointing to us empirical realists like Dennett and myself.
There are geeky kids around the world perhaps dying to know what it is like to be a bat, or even Batman ;-) Let's make an empirical phenomonological attempt to answer the question, preferably in the first person ;-)
So here I am, a batman, hanging out with my friends on the ceiling of the bat-cave. Why not standing? Because evolution developed hanging from the ceiling as a good defence against ground-based predators such as badgers and snakes etc. The downside (sic!) is that we need to go for a flight if we need to take a crap. Tip : never crap in your sleep! ;-)
I'm told that it's dark in the cave, but I'm blind and "see" by echolocation - bio-sonar, as do toothed whales and dolphins, shrews and swiftlets (a cave-dwelling bird). What's that like? Let me try to explain.
When I'm hanging from my perch (which is not usually 5½ feet long ;-) I emit ultrasound pulses about 100 milliseconds long about 5-10 times a second. Sound travels in air roughly 34 meters in 100 milliseconds,so I can only detect objects as far away as 17 meters (the sound has to travel out and back). The ultrasound we insectivorous aerial-hawking bats use has a call frequency between 20 kHz and 60 kHz. In this resting phase we use a constant frequency narrow-band signal because it is more efficient; we can sum the echos over the whole length of the pulse. Remember the intensity of the echo decreases with the fourth power of the distance to the target :-( Apropos intensity, we aerial-hawking bats can send a 133 dB pulse, which we can decrease to 60 dB when closer to our targets (to avoid deafening ourselves).
We constantly do an incoherent cross-correlation of the returning echoes, what you radar geeks would call a filter bank receiver. Thus we can pick out the doppler-shifted returns caused by moving targets and by the beat of prey-insect's wings. I know the range to the target from the echo's delay. Slight difference in the arrival time of the echo pulse at my left and right ears tell me the azimuthal angle. The lobes in my ears give me rough elevation information. So I know where the target is. The single-sideband doppler shift tells me the target's velocity. So I know where the target will be when I'll arrive there by dead reckoning :-)
So I drop from the batcave ceiling, accelerating to flying speed effortlessly by gravity's pull. Pull up and aim for the dead-reckoning interception point.
Now I switch my bio-sonar over to swept FM (frequency-modulated) pulses because this mode is better for hunting prey while flying in close, cluttered environments. The FM broadband signal - with harmonics - gives extreme range precision : a resolution of less than a millimeter and helps reject clutter. As I approach the intercept point I increase the pulse frequency from 30 to 200 Hertz (which implies a range limit of 5 cms). Homing sonar takes over from the dead-reckoning navigation and SNAP, I have caught the prey :-)
So that's part of what it like to be a bat. If you came for a story on batman sex because some of us batmen have huge spikes on the penis, I'll disappoint you. Go read this article instead ;-)
Chaos of the clocks
Back to the Future Day
Kunovice Aircraft Museum
Hungary : Aggtelek NP
Ada Lovelace Day
Narodny Park, Poloniny
High Tatra (SK,PL,UA)
The High Tatra (SK)
Selfie shirt ;-)
What is it like to be a bat
Supermoon lunar eclipse
Stanislav Petrov :-)
Ain Bulldog Blog
Finding life hard?
Not Always Right
Rants from t'Rookery
Spork in the drawer
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May Jun Jul Aug
Jan Feb Mar Apr
May Jun Jul Aug
Sep Oct Nov Dec
This blog is getting really unmanagable, so I've taken the first 12 years' archives offline. My blog, my random decision. Tough shit; YOLO.
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 mir ihren Inhalt nicht zu eigen.
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Blog Dewey Decimal Classification : 153
FWIW, 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 ;-)
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