Wednesday, 19 November 2014

Wednesday Science Limerick: The Speed of Light

If you measure the speed of the light
From a source, whether feeble or bright,
Whether photon or wave,
Out in space, in a cave,
It’s the same, be it morning or night.


However you measure it, the speed of light in a vacuum is exactly 299,792,458 metres per second. It doesn’t make any difference if you think of light as a string of particles called photons, or as a wave.

Friday, 7 November 2014

Limericks & An Interruption to Normal Services

The dove saw the hawk as a threat
But its plans to escape were upset
When a window it hit
So I wrote this obit
And the hawk ate a feathered bagette

This morning I was interrupted by a large thump on our sitting room window, and I realized at once that a bird must have flown into it at speed. However I wasn't the first to get to the Collared Dove ...which had almost certainly flown into the window trying to escape from the Sparrow Hawk!

However this is a good opportunity to explain why I missed this week's Wednesday Limerick and why posts of all kinds may be a bit erratic at least until Christmas.

I am not expecting to go as dramatically as the collared dove but my wife and I have reached an age where parts are beginning to wear out and we need to think about our future living requirements. These will almost certainly include a ground floor bedroom with en-suite facilities. We prefer to remain in the small town where we have lived for the last 50 years and having looked at property availability the most sensible option would be to convert our integral garage to provide the extra space we need. However the garage is currently full almost to the roof with junk accumulated over the years - so we have set ourselves the target of downsizing the clutter ...

Thursday, 30 October 2014

Wednesday Science Limerick: Computers and Cosmic Rays

A transistor is just a fast switch
A computer has millions and which
If they fail to work right
Your plans they will blight
But the experts just say "It’s a glitch."


The very first computers used large valves as electrical switches and these often failed. The coming of the first transistors greatly improved reliability, and integrated circuits involving millions of transistors on a single chip has reduced that possibility of a single transistor failing when being used to almost nothing.

But not entirely. Individual transistors in an integrated chip are now so small that they can be affected by alpha-particles caused by radioactive decay in other components - and by the even more energetic cosmic rays - which becomes important in computers which are to be sent into space.

Where appropriate self-checking and redundant circuits can be used to minimise the possibility of the system becoming non-functional. 

If you are interested in the technical side you can find a detailed history and explanation at How Cosmic Rays cause Computer Downtime (pdf).

However for the average users with a pc, laptop or android system, 99.99% percent of gitches are going to be due to software bugs, malicious viruses, or good old human error.

Wednesday, 22 October 2014

Wednesday Science Limerick: Comet Siding Spring

The comet was named Siding Spring
It came as if thrown from a sling
From the distant Oort cloud
Passing Mars as it ploughed
Round the Sun, then it left with a swing.



The Comet Siding Spring, which originated in the Oort Cloud, passed close to Mars on 19th October and while it was photographed from the Mars Opportunity Rover and Mars Renaissance Orbiter (above) we will probably have to wait for the most interesting findings until a conference to be held in December. In the mean time the best places to find the latest news is on Wikipedia under the comet's official name C/2013 A1.

The Computer that was born in a Tea Shop



An excellent video of the origin of commercial computers in the UK.

I started work on a Leo Computer (see Working with Leo III at SMBP 1965-7) and the basic ideas behind CODIL arose when I was looking at ways to upgrade from the batch system provided by the Leo to an early interactive system.

Wednesday, 15 October 2014

Wednesday Science Limerick: Political Climate Deniers

In New York a great crowd in the city
Said that more climate change was a pity
While some congressmen fools,
Just as stubborn as mules,
Formed a "climate deniers" committee.

The most important box, in which we are all trapped, is the planet on which we live - and climate change is a very serious long term threat. I first got seriously interested in the subject in 1990 (see Global Warming - To Australia in a Box) and every year I get more worried as the signs of change become more and more obvious, and so little is being done.
This weeks limerick was inspired by Donald Prothero's article Signs of Hope—and Despair—on Climate Change which starts with the news that a quarter of a million people demonstrated on the streets of New York urging that action was needed at the United Nations level. Clearly a lot of people are worried - but is it too late to avoid very dramatic changes that will effect us all?

His article goes onto despair about the many scientifically illiterate politicians who sit on the US House Committee on Science, Space, and Technology. If you have missed out on the kinds of nonsense arguments they are using to try and push climate change issues into the long grass you should read DOnald's article - and realise that as long as the public (everywhere and not just the USA) continues to vote for eloquent fools there is no hope of appropriate action being taken.

However there was one other interesting bit of news from the USA which may be a good sign. The Pentagon has issued a report 2014 Climate Change - Adaptation Road Map (pdf) which takes a serious look at the way that climate change could affect the U.S. military policy. IN addition to obvious matters (such as rising sea levels affecting coastal installations) it considers the potentially serious destabilization effects on governmens and economies around the world and suggests that climate change could be a "threat multiplier" which could make make increased terrorism more likely. While I do not support all aspects of US military policies I am delighted that a major organisation in the US is beginning to realise that the most important medium term threat is social disintegration of the most effected countries.

Climate change gives us all cause to fret
And the future look grim, I would bet.
There'll be more CO2,
With the seas rising too,
And so hot we’ll all end in a sweat.