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In those first moments that the frozen flurries start to fly through the air – before lips chafe and sludge-soaked trouser legs renders everything miserable – there’s an undeniable temptation to run out into the falling snow, tilt your face to the heavens and try to capture some of those flakes on your tongue.
But is it actually a good idea to do so? That’s what Sean Moncrieff will be asking today, when he chats to Anne Bramley, a food writer whose grandmother used to whip up ice cream out of a fresh bowl of blizzard snow.
Tune in live todat at 2.20pm: http://www.newstalk.com/player/
When it comes to snow, we tend to think of it as being that pristine shade of white – until other influences of humankind and animal lend it different hues.
But when snow falls out in the wilderness, where it can stay on the ground for months on end without coming into contact with a car’s exhaust or a cocked leg, by the time spring’s heat comes to thaw it out, it can be tinted ted, orange, green and yellow.
Of course, you might think you already know why snow might have taken on that yellow glow, but there are other factors – and about 350 varieties of algae which love the near-frozen, slightly acidic misery of life on the practically nutrient-less frozen tundra. And they brush the surface of snow with a rainbow of colours.
It’s not merely blooming algae, though, as snow drifts can be crawling with microscopic tardigrades, tiny mites invisible to the naked eye that also go by the names waterbears and moss piglets. The eight-legged creatures have the capacity to thrive in environments marked by vastly ranging temperatures scales, and can live for almost ten years without consuming food or water – which raises some interesting questions about the potential for the frozen worlds of our solar system to support life.
Snow and ice can also take on shades of deep and dark blues, and this isn’t due to algae; when old snow gets compressed, crushed down by more snowfalls over decades and centuries, it creates a glacier. In Antarctica, some of the ice can be dated back 800,000 years, taking on blue and green hues.
Snow and ice has the ability to reflect the entire spectrum of visible light, which is why it looks white to the naked eye. But glaciers are made of layers of snow piled high and deep, a dense mass of compacted ice crystals, the surface manages to absorb more red light than blue. It’s this scattering of blue light that hits our eyes. This is actually different from the reason why the sky is blue – in that case, molecules and dust scatter blue light better than red, except for at the horizon, which is why at sunrise and sunset, ravishing reds fill the skyline.
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