Here is a 'sun dog' I saw yesterday evening. The sun itself is just off to the left of the picture. The sun dog is the bright feature in the middle.
These sun dogs appear when sunlight is refracted through hexagonal ice crystals which act as prisms. They are quite common - much more frequent than rainbows for example - but usually people aren't looking out for them so they get missed.
I just remembered this one.
A tennis club with 200 members organises a tournament. If a player loses a match they are out of the tournament, and there are no draws. How many matches are needed to decide the tournament winner?
In a cross-country run, Sven placed exactly in the middle among all participants.
Dan placed lower (i.e. did worse than Sven), in tenth place, and Lars placed sixteenth.
How many runners took part in the race?
(This is another mini-classic, I'll try to recollect where it was first published.)
That's the startling conclusion of an article in the March edition of Scientific American.
There are currently about 4400 different minerals on the Earth's surface but originally there would have been much fewer. Volcanic action, tectonic processes and atmospheric weathering gradually increased that number to a couple of thousand.
But with the coming of life and in particular photosynthesis the atmosphere gained oxygen and this led to the emergence of novel minerals, oxides and so on. About 2500 new species of mineral now appeared.
So is seems minerals co-evolved with life, and if there is extraterrestial life, perhaps on planets with quite different surface chemistry, it may be those planets likewise have a richness and diversity of minerals, compared with lifeless ones.
Hello stardust
For that's what you are, reader. Here's the story, please read it, it concerns you and I. Sorry it is a bit long but it took billions of years to happen, so it is hard to squeeze into one blog post.
Long long ago when the universe first began there was only hydrogen. Later some helium formed. Then some lithium and probably a little beryllium. Even a little carbon. But nothing very heavy.
After quite a while some large stars formed. In the heart of these stars helium was forged from hydrogen and the change threw off lots of energy. The helium could even form other elements by combining and this too produced energy. This energy flow kept the stars inflated, although gravity was trying to make them contract.
Over time these stars began to run out of hydrogen and helium, and eventually they collapsed. This is what causes a supernova! The star implodes violently in a short time -- days only -- but then as it smashes in on itself all sort of new elements are formed by the pressure -- including many necessary to life. Before the implosion there might have been a little carbon perhaps but no iron for blood, or oxygen for breathing.
Now this explosion blew the heavy elements formed out at great velocities and over billions of year the atoms ended up with some other dust, and some hydrogen and helium, and gravity made it swirl together. This formed a new star and some planets.
But some of the little planets were too small for their gravity to hold on to all the hydrogen and helium they began with. Part of their hydrogen combined with oxygen to make water, which has remained. But mostly what was left was heavier elements -- think rocks. Still all the same the wet bits on the surface acted a home for the evolution of life.
Of course this life used many heavy atoms from supernovas billions of light-years away and billions of year before. You and I would not exist without the dust from those ancient stars.
Literally stardust.
Well they didn't say that exactly, but in a study it was found that homes in which someone had a degree were more likely to have a cat.
Has this any connection with the suggestion some time back that Apple = cat lovers vs. Microsoft = dog lovers?
Here are some lynx
http://www.timesonline.co.uk/tol/life_and_style/article7017260.ece
Here's a red dwarf, courtesy of Swinburne University. Such an object might be stable for as long as a trillion years.
http://astronomy.swin.edu.au/cms/astro/cosmos/R/Red+Dwarf
How many red dwarf stars are there in the observable universe (very roughly) and what is their combined mass (even more roughly)?
(Only estimates required but we want to see you working! Well roughly.)
A man is twice as old as his wife was when he was the same age as she is now. She is 30, how old is he?
(Both OU students of course!)
J.D. Salinger has died.
The immortal novel he wrote way back (1960?), The Catcher in the Rye, is a magic book, probably the best or second best American novel of the 20-th century. He wrote some other stuff - short stories - and they are good too.
Something I remember from these stories is an attachment to haiku, I think a famous one by Issa is there somewhere
Don't swat it!
The fly is rubbing
Its hands and legs
Salinger then gave up publishing any work and famously became an extreme recluse, refusing all publicity and repulsing interviews.
That doesn't seem so surprising or unreasonable; he seems to have been drawn towards a contemplative life, and had an interest in Zen.
Many years ago I heard a talk by Alan Kay, a pioneer of personal computing and a true visionary.
He was one of the best presenters I've ever heard and influenced my approach to speaking to audiences, ever since that time.
He had a dream: a lightweight, sturdy computer, with no separate keyboard, no need to be plugged in all the time, that you could take anywhere, would let you communicate wirelessly with anyone, anytime, access all human knowledge, and read any book, right there on the screen, which would be oh let's say A4-ish.
So is the iPad the realisation of Alan Kay's dream? Well I think comes pretty close.
We all know the rainbow, which is the result of sunlight (or any other light) bouncing around inside a raindrop. The different colours return at different angles and so we see the coloured bands, like light shining through a prism.
Sunlight may also bounce round inside tiny prisms of ice. These of course are six-sided, like snowflakes. This can produce many different sky effects and where I live -- Cambridge UK -- the one called 'sun dogs' is quite common, in fact much more frequent than rainbows.
Most people have never seen them though, because they don't know where or when to look.
Once you have seen a thing you will probably see it again many times, even if you never previously knew it existed. Learning makes us more aware.
Visit this site and you can find out more. The evening sun dogs are the ones I have often seen.
Sadly there are no sun cats.
I've always thought symmetry was heart-breaking and snowflake patterns marvellous in their variety - and their temporary existence. Bentley, the New England farmer who photographed so many snow crystals over 40 years (see earlier blog post snowflake(1)) lamented that each was unique and so beautiful, but gone forever in seconds or less.
Yesterday some of Bentley's original photos - plates I guess - were at auction and this was reported in many newspapers. Go look
When a whale dies it usually sinks to the bottom. This is called whale-fall.
The corpse will then nurture a diverse range of organisms, of a period of many years. They follow a succession - like trees and shrubs in a forest growing up in a cleared area once it is left alone - and form a unique ecosystem. A range of organisms are specialised to live only in these whale-falls.
That is quite surprising - to me anyway - but even more so is that fossil deposits have been found that looks like plesiosaur-falls: giant marine reptiles from long before whales existed died and sank and their carcasses supported communities much like those of present day whale-fall ecosystems.
Researchers have revived an idea and a question that has been asked before, probably many times.
Can we see new colours?
For example Terry Pratchett's first DiscWorld introduced an eighth rainbow colour octarine, a 'fluorescent greenish-yellow-purple'.
It seems the answer is yes!
The question is not whether our eyes might somehow respond to ultra-violet, like a bee's, or have more types of colour receptor, like some fishes have.
It's concerned with a vivid subjective experience of a 'new' colour, what I think philosophers would call qualia. Qualia are hard to derive just as a consequence of the objective facts (thus knowing the wavelength of light may show that it is red but does not explain its redness, the experience).
The new colours that people can be induced to experience are reddish-green and bluish-yellow. Scientific American for January 2010 reports these experiments, which improve on ones done many years ago but not fully appreciated at the time.
But all the same these experiences are dependent on the physical properies of the brain, it seems. So are they true qualia?
A term from Zen. The idea is that a beginner's mind is open. From Zen Mind, Beginners' Mind by Shunryn Suzuki 'In the beginner's mind there are many possibilities, in the expert's there are few'.
I think teachers should always try to keep the beginners mind, so we rediscover our subject over and over again, and don't ever forget what it was like when we were just starting out.
Long ago in the 1950's Dylan Thomas was famous as a poetry and a reader of poetry, an almost Byron-like figure.
He had then a great following and has had since a great influence.
However I never had listened to him reading, except for 'Under Milk Wood'. So perhaps I thought the poet over-hyped.
But I found recordings the other evening on Spotify and was deeply impressed.
I can drag from Spotify into Moodle - see if it works.
That's the famous pi as in Π. (I think it should have curly bits but the standard HTML character doesn't show any.)
Fabrice Bellard has just calculated this constant to
2699999999999
decimal places, using only a PC, see
This is a new record, for any computer.
The result occupies a bit over 1 TB (that's 10 Olympic swimming pools). I think you will not want to download it all. Parts of it are available
This is certainly a triumph of human ingenuity and spirit. But it's hard to say whether all the effort that goes into any sort of record-breaking is worth it or not. I'd be really glad to know other people's views on this one.
Miss Smilla's Feeling for Snow is a famous novel. But Wilson Bentley also had a feeling for snow and was the pioneer of snowflake photography, see
http://en.wikipedia.org/wiki/Wilson_Bentley
A more recent photographer of snow crystals is Kenneth Libbrech, see
http://www.newscientist.com/gallery/dn16170-snowflakes/5
These images are all wonderful.
Looking at snowflakes many have asked how each of the six arms of the snowflake 'knows' how to keep itself in symmetry.
Here's another minature, this time in a different tradition.
Again this is actual size.
I've always been interested in folk art.
Below is an example of small-scale decorative art, in canal boat 'roses' style. You see it more or less actual size, if your browser is on on standard settings.
There is some evidence we can and in an easy way, by exploiting the effect of 'psychological distance'.
Instead of thinking about a problem solely in terms of here and now, we should project our mind to distant places and times, try to consider the problem from another person's standpoint and so on. How would the problem appear to an inhabitant of a planet billions of light years away?
Research reported in Scientific American suggest this technique may really help us to be more inventive and creative.
And how did the prisoner divide the rope?
New Scientist surveyed the latest research.
Dogs vs cats: The great pet showdown
Cats win on
Brains, Popularity, Vocalisation, Supersenses, Eco-Friendliness
Dogs win on
Shared history, Bonding, Understanding, Problem solving, Tractability, Utility
So you see that's Cats 5, Dogs 6. But was it a fur contest?
More specifically there is some recent research to suggest that trying to answer the TMA (say) very quickly without any study of the unit - just jot down the best guess you can come up with - and only afterwards reading the relevant bits of the course may improve retention significantly. See http://www.scientificamerican.com/article.cfm?id=getting-it-wrong&sc=MND_20091029
In fact it seems the effect could apply if we do no more than for example try the SAQ before the related section, or even read the unit introduction, section or unit summary etc. before tackling the body of the unit.
I found this idea intriguing and intuitively appealing, but of course that isn't evidence.
To me deciding whether you should trust something you read on the internet is no different from evaluating a printed source. The only way to do it is for each of us to learn critical skills and apply them ourselves. The responsibility of making a judgement can only ever be partially delegated to traditional authorities.
It might seem that an encyclopedia, for example, will be trustworthy because the articles are written by established experts, and carefully reviewed. True this ensures that in most cases what is published is free from serious factual error. However it will still reflect the particular viewpoint of the author (and the editor), which may be quite partial when deciding what to include, which parts of the topic to emphaise as important, and what the significant areas of future developement are likely to be. From any one article the reader can only ever get a one-sided impression.
In addition, bias has been introduced by the mere act of choosing what topics the encyclpedia has articles on and whch not.
Only by consulting multiple sources and comparing can we form a balanced view, and this process must always involve us taking an active part. No panel of experts can ever be relied on to do it for us.
For these and other reasons I cannot believe that the recent proposal by A.C.Grayling, see
could ever achieve what it sets out to do, which is to somehow validate the web, so that learners could be directed only to reliable sites.
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