This coming Sunday at exactly 8:03 a.m. Mountain Standard Time, the Northern Hemisphere’s astronomical winter officially begins with the winter solstice. This will produce the shortest day and the longest night of the year.
The
thing is, all of this winter, spring, summer, and autumn nonsense exists
because the blue planet we are affixed to rotates on an axis about 23.5 degrees
off perpendicular to the plane of the ecliptic. Or, as I might explain it to my
drinking buddies in East Helena, Montana: “The Earth is tilted in its wonky
orbit, Dude.”
You
are going to have to take my word on the tilt thing because you won’t feel it.
Counterintuitively,
the Earth is not farther from the sun during winter. In fact, we are actually a
little closer in our orbit than we are in summer. The cold has nothing to do
with distance and everything to do with angle. Our hemisphere is tilted away
from the sun, spreading its light thin and low across the landscape, shortening
our days and weakening the warmth that reaches us. You won’t feel the
difference in distance either way, but you certainly feel the loss of direct
sunlight. And don’t forget the snow.
You
may already know all this, but you might not know that the placement of our
house on the plateau above the lake was predicated on the tilt of the Earth.
Specifically, the house was positioned to take advantage of how that tilt
alters the track of the sun across our sky from season to season. The year
before we built, we drove stakes into the ground where we planned to build and
watched how the sun arched overhead. Based on that, we repositioned the house
so the sun passes directly overhead in summer. As the sun’s path shifts toward
winter, our orientation invites warming sunlight deep into the house through
our front windows. It is our small, deliberate agreement with a tilted planet
to let the light in when it matters most.
—Mitchell
Hegman
No comments:
Post a Comment