Autumn Colour

Sydney does not have the dramatic changes of season that can be experienced in some other parts of Australia or other countries. This is easy to understand when we consider that the midday temperature in Sydney on the winter solstice is often comparable to the midday temperature on the same June day in parts of England.

It should be noted, in passing, that the vast majority of Australian natives are evergreen. The Australian ‘bush’ remains green all year, while the imported species turn various shades of yellow to red and shed their leaves.

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A Nyssa Sylvatica colours up against a backdrop of a Sydney Red Gum (Angophora species)

In the past week, we have had a succession of typical autumn days – maximum temperature in the mid twenties Celsius, with overnight minimum around 10 Celsius.  The clear blue skies add to the enjoyment of this season, even if the the bowls don’t always go where they should.

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While enjoying such gorgeous weather, as well as watching some trees change colour, we celebrate the colours of Sydney autumn with many flowers as well. There is an abundance of blooms on our Sasanqua Camellias, which began flowering in early March, and are still going strong.

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The Gordonias (sometimes knows as Fried Egg Plants) are also covered with flowers and surrounding themselves with a carpet of spent blooms. On past experience, this will continue for the next month or so.20130425_Autumn_006

Some roses are in their third or fourth flush for the season. This one is called Seduction.

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On a recent garden visit, we saw some delightful, and different, Salvias.

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The air is heavy with the ‘vanilla custard’ fragrance of this Heliotrope, called “Cherry Pie”.20130428_Autumn_009

Not to be outdone, a Banksia stands to attention, representing Australian natives.

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A Lifetime of technical Evolution: Part 3 – The Laser

It would have been 1964 (in third year Physics at Sydney University) that we first learnt about the MASER (Microwave Amplification by Stimulated Emission of Radiation). Coincidentally, 1964 saw the Nobel Prize in Physics awarded to Nikolay Basov and Alexander Prokhorov (who described the theory at the Lebedev Institute in 1952) and Charles H Townes (whose group built the first ammonia maser at Columbia University in 1953), “for their research in the field of stimulated emission”.

An optical version of the maser was first proposed in 1957, and originally called an “optical maser”. In the same year, 1957, Gordon Gould (working at Columbia University under Townes)  is credited with coining the name “LASER”, the acronym for Light Amplification by Stimulated Emission of Radiation. Gould built his first laser in 1958, but was tardy in filing for patents, as a result of which his application was refused and the invention exploited by others. It took twenty years before the patent war was won, and Gould was finally granted patents in 1977.


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The physics of the laser.  Source: V1adis1av (Own work) via Wikimedia Commons

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Helium-Neon laser demonstration at the Kastler-Brossel Laboratory at Paris VI: Pierre et Marie Curie. The glowing ray in the middle is a discharge tube (akin to that of a neon light), it is not the laser beam. The laser beam crosses the air and marks a red point on the screen to the right.  Source: David Monniaux via Wikimedia Commons


So, in this lifetime, lasers have been proposed in theory, conceived, built and developed to the myriad of applications they now serve (for an impressive, if not exhaustive list, click here). From medicine to mining, industry to entertainment, military to domestic, lasers are part of our life today.  Lasers are used to perform delicate eye surgery, to guide missiles, to cut and weld components, to read barcodes. In the home or office, lasers are used to point at a presentation slide, in the desktop printer, and to read data on CDs and DVDs. Lasers can be seen illuminating the Sydney Opera House ‘sails’ or Stone Mountain, Georgia, in a ‘laser light show’.

In fact, lasers have proliferated in ways almost unimaginable less sixty years ago.

Let us not forget the maser. Although perhaps overshadowed by its ‘offspring’, the maser is employed in astrophysics and communications. Perhaps the most important application is the use of the hydrogen maser as an atomic frequency standard and with other atomic clocks, provides the International Time standard.

Heidelberg

Our first glimpse of the Heidelberg Castle is from one of the narrow streets leading from the river up to the main street.

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We have learnt that the castle was built as early as the 13th century. It ranks as one of the most important Renaissance ruins north of the Alps. One resident was the ruler of the Palatinate and Heidelberg, Elector Friedrich V who, in 1613, married Elizabeth Stuart. She was the daughter of James I of England, and the marriage was one of political convenience to bond their two Protestant states.  Unfortunately for them, Catholic forces defeated Friedrich’s in 1622, taking possession of Heidelberg, and forcing the couple to live out their lives in exile.

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At a height of 80 metres above the old town, the castle has an imposing presence.

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Heidelberg is also known for Hauptstrasse, at about 1.6km, thought to be the longest pedestrian street in Germany. We are faced with a choice – to climb to and explore the castle, or to explore the shopping street. With rather limited time at our disposal, and some cravings for coffee, wandering the shopping street wins! We are not disappointed.

The coffee and cakes are indeed very good.

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There is something about watching a fountain when it is raining

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It takes more than a shower or two to deter the window shoppers on Hauptstrasse.

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The Church of the Holy Spirit was built over 150 years in the 15th and 16th centuries and faithfully restored after a fire in the 18th century. It was shared by Catholics and Protestants, sometimes simultaneously, over several centuries.  Now used exclusively by Protestants, the dividing wall was removed in 1936.

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Not far away, is the interesting facade of the Jesuit Church, built in the 18th century.

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Built as the home of a cloth dealer in 1592, the Hotel Ritter is claimed to be one of the most historically significant and artistically valuable houses in the town.

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It was nice to see a promotion to attract tourists “down-under”.

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Footnote: As Heidelberg is not on the Rhine, our afternoon excursion saw us taken by coach from Speyer to Heidelberg, while our cruise ship continued to Mannheim.  Our coaches took us back to the ship at Mannheim in time for dinner. 

At the appointed pick up point and time, our coach captain was rather concerned that his headcount was two short. It was then I received a text message

“Hold the coach, we’re coming!” 

The length of Hauptstrasse, and the attractiveness of its shops, had taken its toll on our travelling companions.