Twilight


This evening, gloriously bruised skies created a twilight ponder. Twilight struck with realization most of us take her mesmerizing palette for granted. Far from a cosmic constant, twilight requires atmosphere to scatter rays of light in advance and conclusion of a visible Sun above the horizon.

Civil twilight falls when the sun is 6 degrees below the horizon. In the morning this is known as dawn, in the evening, dusk. This is the limit at which twilight illumination is sufficient, under good weather conditions, for terrestrial objects to be clearly distinguished; at the beginning of morning civil twilight, or end of evening civil twilight, the horizon is clearly defined and the brightest stars are visible under good atmospheric conditions in the absence of moonlight or other illumination. In the morning before the beginning of civil twilight and in the evening after the end of civil twilight, artificial illumination is normally required to carry on ordinary outdoor activities.


Nautical twilight begins when the Sun is 12 degrees below the horizon. At the beginning or end of nautical twilight, under good atmospheric conditions and in the absence of other illumination, general outlines of ground objects may be distinguishable, but detailed outdoor operations are not possible, and the horizon is indistinct.


Astronomical twilight defines a Sun 18 degrees below the horizon. Before the beginning of astronomical twilight in the morning and after the end of astronomical twilight in the evening the Sun does not contribute to sky illumination; for a considerable interval after the beginning of morning twilight and before the end of evening twilight, sky illumination is so faint that it is practically imperceptible.

Civil, nautical, astronomical, three clearly defined twilights that forgot to mention – twilight is also a colour, emotion and source of cosmic wonder unique to our planet.

 

Diamond Rain, Bergs and Liquid Floaters


Earthly diamonds begin as carbon deposits 100 miles or more below the surface. Location is everything – carbon heated to 2,000 degrees Fahrenheit, squeezed under pressure of 725,000 pounds per square inch, lucky enough to cool quickly by hitching a ride on upward flowing magma, become diamonds.

Science knows there’s more than one way to make a diamond. Just as bakers adjust recipes for high altitude cooking, the cosmos creatively adapts to unique circumstance. Earthly optimists turn lemons into lemonade, cosmic forces create diamonds from carbon in the unlikeliest¬† of places.

Science has speculated for some time that chilly cores of Neptune and Uranus glisten with diamonds. A few years ago science singled out 55 Cancri e, an exo-planet 40 light years from our solar system as a planetary body comprised almost entirely of diamonds. Recently, science said – “new data available has confirmed that at depth, diamonds may be floating around inside of Saturn, some growing so large that they could perhaps be called ‘diamondbergs,'”. Diomand-bergs, good grief! What does that even mean?

Apparently behemoth lightening storms on Saturn and Jupiter create elemental carbon in the form of soot and graphite. Falling deep into the atmosphere, heat and pressure produce diamonds of unfathomable girth. Deeper still, extreme heat and pressures melt solid gems into diamond rain. From diamond-bergs floating in a hidden sea of fluid hydrogen and helium, to other worldly ghost clouds of diamond rain a simple truth emerges – the universe sparkles, even in the shadows it knows how to bake a diamond.

https://www.space.com/23135-diamond-rain-jupiter-saturn.html

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