Wednesday, 12 June 2013

A Star is Born and Dies

Full marks to BBC4 for putting on this science epic describing the life cycle of the stars and how they formed the universe. I wanted to preserve a simple summary and now offer it. Hopefully it will add something to blog readers appreciation of the night sky. 
     Everything started in clouds of gas and dust which can be triggered to coalesce under gravitational attraction. As the condensation takes place, heat is evolved and light emitted. At high enough temperatures, hydrogen fusion to helium occurs in a chain reaction that releases enormous amounts of energy. That is the position of our middle aged sun. At the moment after 5 billion years, it is half way through part one of its life cycle, having used up half its hydrogen. It’s relatively stable as the gravitational attraction crushing it is balanced by the nuclear fusion which is pushing to blow it apart.
     After all the hydrogen in the core has fused in another 5 billion years, the sun will turn into a red giant, swelling several thousands of times to gradually swallow the planets in its solar system including the earth. So there’s plenty of time to plan an escape to find another solar system. In any case the male Y-chromosome is said to have only another 200,00 years of viability so perhaps we won't be around to be bothered. At this point the red giant fuses helium to form carbon and oxygen, important building blocks for life on earth. They have cooler surface temperatures hence the red colour.
     The final evolutionary star state is the white dwarf, where an inert mass of oxygen and carbon builds a kind of cinder at the centre. Sirius B, the smaller component of the Sirius binary star, is the nearest example at 8.6 light years away. It no longer has a fusion energy source so becomes very dense under gravitational attraction balanced only by electron repulsion pressure. There are mass limits however above which electron pressure fails to hold the white dwarf together and a supernova explosion occurs triggered perhaps by accruing material from a companion star. This occurs through rising temperature igniting carbon fusion to iron, triggering a runaway nuclear fusion that generates the heavier elements above iron and expels them into the solar system, helping to form new stars.

     The planets of our solar system are but the debris left over from the formation of the sun; a kind of afterbirth and a far cry from the earth-centric doctrine of the medieval Catholic Church that Galileo was severely punished for challenging.

Novels by Alan Calder
The Glorious Twelfth
The Stuart Agenda published by Willowmoon


Friday, 7 June 2013

The Highland Clearances- A visit to Caen village in Kildonan Strath

The Highland Clearances were a dramatic ethnic cleansing where the usurpers were not other humans but sheep. The origins of the debacle are complex but were labelled by the landowners of the time as 'Agricultural Improvements,' made in the name of increasing the profitability of their estates. We also have to understand that by the early nineteenth century, the relationship between landowner and tenants had changed dramatically during the previous hundred years. Before the 1745 jacobite rebellion, tenant farmers were mainly part of the feudal clan system and valued for their ability to bear arms and fight fiercely for their chief. After the rebellion the clan system was supressed and many of the chiefs anglicised, a condition that required money rather than men at arms for support. Sheep were much more profitable than tenant farmers.
     The Countess of Sutherland, in whose name the worst of the excesses were perpetrated, was born in the south and spent most of her life in Edinburgh and London. She had clearly little emotional attachment to her tenants, although considerable funds were spent on unsatisfactory resettlement in coastal villages; for many, just stopping points on the way to the emigration ships. Around 100 displaced residents left Kildonan in June 1813, including a boatload who went to Hudson's Bay in northern Canada and had to survive the harsh winter before moving on in spring to the red River Settlement around Lake Winnipeg. The Timespan centre at Helmsdale has a message board for descendants from all parts of the world to reconnect via the Timespan project.
     The ruins of Caen village (not to be confused with Caen in Normandy) lie a few miles up the Kildonan Strath from Helmsdale in a beautiful side valley with its own burn. The visit was part of Timespan's Excavation project aimed at better understanding the sequence of events that led to the removal of the inhabitants. The visit was guided by enthusiastic heritage officer, Jacquie Aitken.
 The outline of the township, a few longhouses and other buildings could be discerned, wedged in time between, the sheepfolds of the supplanters and the neolithic cairns of long distant generations who lived there 5000 years ago.  Higher up the valley with an awesome view, better preserved walls suggested a superior dwelling while a nearby Neolithic souterrain kept the timescales in parallel. During our visit archaeologists from Orkney were conducting a geophysical survey to understand the layout and help choose the most fertile digging sites. Included in the project is a Virtual World application which will enable visitors to see inside the houses as they might have been in reality. It is intended that the archaeological details gleaned from the dig will paint  more authenticity onto the virtual canvas.
My final question, I'm sure asked by many was, 'Did the brutal lairds do the people a favour by obliging them to leave supposedly for a better life?' For me the answer has to be a qualified 'Yes.' Certainly not for the generation that endured the stress and hardship of removal but for successive generations thereafter. I'm sure that they were able to progress with more land and opportunity than in the mid nineteenth century Highlands or the slums of Glasgow. It's obvious that in time with or without clearances, depopulation continued in the Highlands and Islands as the young moved away seeking opportunity to the tune of the relentless march of modernity.

Novels by Alan Calder
The Glorious Twelfth- Buy Links

Also by Alan Calder, The Stuart Agenda published by Willowmoon