Wednesday, September 17, 2008

A few of my favorite things

The Daily Mail's headline read Pictured: Rare upside-down rainbow spotted in the UK. The Telegraph's headline read 'Upside down rainbow' caused by freak weather.

The Daily Mail's article:
Relatively rare in Britain, the arc only appears when sunlight shines at a specific angle through a thin veil of wispy clouds at a height of around 20,000 to 25,000 feet.

At this altitude the cirrus clouds are made of ice crystals, the size of grains of salt.

Meteorologists say the clouds must be convex to the sun with the ice particles lined up together in the right direction to refract the light.

This results in the sunlight bouncing off the ice crystals high in the atmosphere, sending the light rays back up and bending the sunlight like a glass prism into a spectrum of colour.

Renowned astronomer and writer Dr Jacqueline Mitton was lucky enough to capture the optical phenomenon on camera near her home in Cambridge last Sunday.

'The conditions have to be just right: you need the right sort of ice crystals and the sky has to be clear.

'It's quite surprising for this to occur somewhere like Cambridge, usually it is in places that are colder.

'We're not sure how big an area it was visible over, but it was certainly very impressive.'

According to Dr Mitton, the colours in the rainbow were intensified by the position of the sun, which was at the optimum spot in the sky of 22 degrees.

The vision was made even more dazzling by the presence of "sun dogs" - gleaming spots on a halo around the sun.

Dr Mitton added: 'It was just an amazing combination of factors that happened at the right time.'

Her husband Simon, 62, an astronomy writer, said: 'The circumzenithal arc is a quarter circle, pointing toward the setting sun.

'The "rainbow'" is much brighter and more concentrated than a rainfall rainbow.'

Rainbows are formed when sunlight is refracted in a raindrop.

But in a circumzenithal arc, the colours are in reverse order from a rainbow, with violet on the top and red at the bottom.

The arc usually vanishes quickly because the cirrus clouds containing the ice crystals shift their position.

Ice particles in high cirrus clouds occur all year round, but circumzenithal arcs are usually obscured by lower level clouds.

Circumzenithal arcs are so named as they go around the zenith - the point in the sky directly above the observer- rather than the sun.

The Telegraph's article:
Freak atmospheric conditions rarely seen outside the polar regions have been credited with causing the formation of an "upside down rainbow".

Normal rainbows are made when light penetrates raindrops and re-emerges out the other side in the same direction but the inverted types, known as circumzenithal arcs, are caused when sunlight bounces off ice crystals high in the atmosphere, sending the light rays back up.

The "smiley faces in the sky" need extremely specific conditions not usually found above Britain.

This picture was reportedly captured on camera by astronomer Dr Jacqueline Mitton near her home in Cambridge last Sunday.
Who defines normal anyway? Are circumzenithal arcs "freaks" or just atmospheric phenomena rarely seen in southern England due to frequent low-lying cloudcover?

I don't live in the UK so I am not very familiar with the differences between the papers. But is the Telegraph really "Britain's No.1 quality newspaper"? How do you define quality in English English?

As a sky watcher, rainbows are one of my favorite things. I did, after all, name my child Iris.

2 comments:

  1. Neither Mail or Telegraph would be regarded as quality by me or DH we read the Guardian or Independent

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  2. But is the Telegraph really "Britain's No.1 quality newspaper"?

    I guess "quality" is supposed to mean "serious journalism." The conventional wisdom is that the national quality newspapers are the Telegraph, the Times, the Financial Times, the Guardian, and the Independent. Of these, the Telegraph is indeed number one by circulation.

    Downmarket tabloids such as the Sun and middle-market papers such as the Daily Mail have significantly higher circulation than the Telegraph.

    "Quality" and "serious journalism" may perhaps be subjective. However I will note that right now the top headlines on the Daily Telegraph website are:
    * South Africa's president Mbeki agrees to resign
    * Damaged Hadron Collider halted for months
    * Suicide bomb hits Marriott Hotel in Islamabad

    The top headlines on the Daily Mail website are:
    * Girl, 19, tortured for 13 hours by two women after being wrongly accused of stealing phone
    * Paris Hilton's ex, Blink-182 drummer Travis Barker fights for life in burns unit after plane crash kills four
    * Revealed: Prince Philip told Downing Stret to 'f*** off' over Princess Diana's funeral

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