Thursday, November 25, 2010

False Dawn

Many have been fooled into thinking that it marks the start of morning twilight. Indeed the Persian astronomer Omar Khayyam referred to this ghostly glow as the "false dawn" in his poem, The Rubaiyat.

When false dawn streaks the east with cold, gray line,

Pour in your cups the pure blood of the vine;

The truth, they say, tastes bitter in the mouth,

This is a token that the “Truth” is wine.

Unlike the stars of the Milky Way, which stretch away from Earth for light-years, the source of false dawn lies between the inner planets of our Solar System. Billions of dust grains orbit the sun in a flattened disk spread out along the ecliptic. Many of these particles were ejected by comets. The dust reflects and scatters sunlight creating a visible triangular glow above the horizon.

It can be seen for up to an hour before true dawn begins to break. Unlike true dawn, though, there’s no rosy colour to the false dawn. The reddish skies at dawn and dusk are caused by Earth’s atmosphere, false dawn originates far outside our atmosphere. You are looking edgewise view into our own solar system.

The sub zero cold, early hours would bring this humongous Zodiacal Light right on schedule each night at Indian Astronomical Observatory, Hanle, Ladakh brighter than the Milky Way and rising to great heights. It was a sight to fix your gaze upon, one could never get used to it.

Hope this image conveys just a little of how I felt the 6 nights I was at that
wondrous place on top of the world.

Ajay Talwar
November 26th, 2010

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