preferentially transmits different visible wavelengths
scattering some colors more than others
so that in the day the sky appears blue,
but at dawn or sunset, across a wider swath of gases,
mainly the red light gets through.
2.
Laboratory experiments show
different gases absorb heat in different amounts,
oxygen and nitrogen being transparent
but water vapor and carbon dioxide nearly opaque
3.
which means that variations
of water vapor and carbon dioxide
regulate Earth’s temperature
like a greenhouse, letting in light
but trapping a variable amount
of the heat that is reflected back.
Mountaineer
“It’s hard to take air for granted
at the top of the Weisshorn
and easier to wonder
why clouds stay in layers
when you’re looking down on them from above.
“Snow up here never completely melts
but hot air rises
so something must be happening to heat
in this thinning air.
“The leeward side of the mountain is dry
but the windward side is green.
Water vapor must condense out of the air
as it’s forced to rise.
“Mountaineers and balloonists know
wind blows in different directions
at different elevations.
Barometric pressure makes this happen, or,
if we reduce to first causes,
sunlight and gravity.
The atmosphere is stratified by gravity
and heated unevenly by the sun.
Wind is air moving in its layers
to even out the pressure.
“People ask me why a physicist climbs mountains.
Even my guides won’t follow me up there.
They think an educated man
with a prestigious degree
couldn’t learn anything important
from a monstrous chunk of rock.
But there it waits like the wise man in his cave
impassive
and taking nothing for granted.”
John Tyndall was the first person to measure the ability of
gases (including nitrogen, oxygen, water vapour, carbon dioxide,
ozone, and methane) to absorb heat, and was the first to prove the
greenhouse effect of earth’s atmosphere. This was the
beginning of the modern understanding that global warming has been
caused by the activities of man.
John Tyndall was the first person to measure the ability of gases (including nitrogen, oxygen, water vapour, carbon dioxide, ozone, and methane) to absorb heat, and was the first to prove the greenhouse effect of earth’s atmosphere. This was the beginning of the modern understanding that global warming has been caused by the activities of man.
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