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Friday, June 4, 2010

Thiruneermalai - Gretna Green and Solar Prominence

Keeping one’s head high – has a different connotation…….. from time immemorial, man has been attracted by the clear sky, the numerable objects that can be observed have all enamoured people. Each region or religion have interesting stories of sky – some fascinating ones as we heard in our childhood days of the moon.

Read somewhere that today is solar prominence day (what ?) there was also something else ‘Gretna green’ - Have heard of these. In one way, Gretna green would compare with our own Thiruneermalai (not for the Divyadesam of Lord Ranganatha known as Neervannan).

Astronomy is the oldest of the natural sciences, dating back to antiquity. In ancient times people related the regular patterns of the motions of celestial objects to prediction of future and recorded the then events in relations to such celestial objects and their movement. It is a wonder that in those days, they were clearly able to differentiate between stars and planets. Most olden cultures including our own have had methodical observations of the night sky and the patterns that were observed. Religious almanacs were prepared in accordance with these studies.

The Solar system revolves the main star – the SUN around which the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto circulate. Besides, there are innumerable other things called comets, asteroids and meteoroids. The Sun provides light and heat and is the reason for life in the system.  Our nearest neighbour is a red dwarf star – proxima centauri – at a distance of 4.3 lightyears away; besides our home galaxy there are many other, nearest being Andromeda – the galactic space thus is a horizon which continues to be explored. The star at the centre of solar system has a dia of about 1392,000kms about 110 times that of our earth. The Sun consists of hydrogen in huge quantity besides helium and heavier elements including iron, oxygen, carbon, neon and others.

Solar prominence are sheets of luminous gas emanating from the sun’s surface – they would appear dark against the sun’s disk but bright against the dark sky and occur in regions of horizontal magnetic fields. Here is a NASA photo of a solar prominence.

The largest solar prominence ever observed reaching a height of 300000 miles from the surface of moon was observed on 4th June 1946 and hence the day – today. Solar prominences are large, glowing clouds of gas suspended in magnetic field loops above the Sun's photosphere. They could not be spotted in white light. They have been observed during eclipses.

To read more of Solar Prominence :  SP

The scientific explanation (as gathered from Wikipedia and is Prominences arise as products of the solar activity cycle. The hot gas that comprises the Sun is magnetized, and as the Sun rotates and the heat of its interior churns its subsurface layer in great convective bubbles, the magnetic field becomes increasingly tangled. Large magnetic loops burst through the Sun's photosphere and into its atmosphere. At the focal points of these loops one often finds sunspots, while trapped in the upper part of the loop is hot (about 10,000 K), glowing hydrogen gas. These glowing loops are prominences, and not surprisingly, they are most common at the height of the solar activity cycle, and decrease in number as the complex magnetic field rearranges itself into simpler configurations and the activity cycle declines. Because the magnetic loops are not static, prominences evolve on time scales of days. As a magnetic loop expands, the pressure of the material inside it may become sufficient to break through the field, and the prominence will then dissipate. The gas inside a prominence flows from one part of the loop to the other as well, making prominences dynamic objects for study from Earth-based and satellite telescopes.

Prominences are typically huge; several Earth-sized could fit inside a typical prominence loop. Graceful quiescent prominences last for up to several days, while their more violent cousins, the eruptive prominences, only last for a matter of hours. Prominences do not appear to be confined to the Sun; evidence exists for gigantic, prominence-like structures on other stars. Some stellar prominences have been suggested to extend as far as an entire stellar radius from the surface of their parent star. Such a structure would dwarf even the largest solar prominences.

Coming to Gretna Green – is touted as a place where many eloping couples get married. This is a village in the south of Scotland near the mouth of river Esk.  In the yores of England, person could not marry without parental consent until age of 21, following Act of Parliament – Lord Hardwicke’s Marriage Act. The Scots were more lenient allowing marriages without such permission at 16. that made young couples elope to Gretna green, a small village on Eng – Scottish border for marriage, where the wedding was performed by blacksmith at roadside toll houses. These marriages were legal.

Thiruneermalai the abode of Lord Ranganatha on a small hill lies in the outskirts of Chennai, off Pallavaram. Here Lord is in reclining, standing and sitting postures. This has been an attractive location for many movies and typically loving couples (a rich girl and a rustic boy) elope to this temple to get married before the chasing group can near them.

Regards – Sampathkumar.

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