Wednesday, July 31, 2019

Blowin' in the Wind: The Dimensions of the Milky Way

("Blowin’ in the Wind" is a periodic feature on my blog consisting of an assortment of nature writings – hymns, songs, excerpts, prayers, Bible readings, poems or other things – pieces I have not written but that inspire me or give me joy. I trust they’ll do the same for you.)

Gail and I will be heading soon to the hinterland of Michigan’s Upper Peninsula, where a highlight we always enjoy while there are its night skies. Occasionally we are treated to some fantastic views of the aurora borealis, the northern lights. But each and every single night that is clear we’re given fantastic views of the cosmos, and I often find myself sitting long with a star map and a pair of binoculars on the end of the dock. Star clusters, nebulae and distant galaxies are not difficult to spot with binocs if one knows where to look, but they’re not my favorite sight. Besides, these are usually ‘pinpointed’ objects, where one does not get a sense of the sky’s awesome vastness, or its almost dizzying three-dimensionality. My favorite sky view? Taking a long look at the Milky Way. It almost always takes my breath away, giving me a feeling of space-flight while I’m at it.

The Milky Way is best seen without binoculars to get this sensation, though a look through field glasses or a telescope always presents an absolutely stunning array of stars not visible even to the best naked eye. After evening twilight in the U.P. in mid-August, the Milky Way runs diagonally in a fairly straight line from the northeast down to the southwest, picking up great constellations along the way like Cassiopeia, Cygnus, Lyra, Aquila, Sagittarius and Scorpio, all rotating clockwise as the night progresses. And the ‘line?’ That is because we are actually looking out ‘sideways’ through our spiral galaxy’s flattened disk, and the concentration of stars presents itself to us as a wispy, cloudy line. One is usually unable to see it from even small cities, with its artificial light typically fading away both the sky’s blackness and the Milky Way’s lightness at the same time.

One can easily get caught up in the complexity and enormity of this galaxy we call home. Over 100 billion beautiful suns and at least as many planets. 100,000 light years across. And up until a mere century ago last year it was thought to be much smaller and, at that, alone in the universe. But then a man named Harlow Shapley worked out its rough vast dimensions, including the placement of our solar system within it, and informed a near disbelieving world. On and on it has gone since, as we have found our galaxy one among many, its address among what is called a ‘local group’ of galaxies within a larger supercluster, which is then itself within an even larger galactic supercluster. And some are even postulating our universe itself may belong to a ‘multiverse’ consisting of numerous universes.

A person need not be overwhelmed by this, though, since, once we are up to considering a galaxy 100,000 light years across, bigness just gets bigger. And God just gets to still be God.

I recently ran across a poem written about Shapley’s discovery and wanted to share it with you. I know nothing about its author, but would be glad to meet her some day and talk about it. Here it is.

The Dimensions of the Milky Way
by Marilyn Nelson

Discovered by Harlow Shapley, 1918

Behind the men’s dorm
at dusk on a late May evening,
Carver lowers the paper
and watches the light change.

He tries to see earth
across a distance
of twenty-five thousand light-years,
from the center of the Milky Way:
a grain of pollen, a spore
of galactic dust.

He looks around:
that shagbark, those swallows,
the fireflies, that blasted mosquito:
this beautiful world.
A hundred billion stars
in a roughly spherical flattened disc
with a radius of one hundred thousand light-years.

Imagine that.

He catches a falling star.

Well, Lord, this infinitesimal speck
could fill the universe with praise.

Indeed. I could not agree more.

The sky is fascinating. It captivated the ancients as they tried to figure out how this whole thing works, and it even mesmerized the Bible writers with awe and appreciation for its (and their) Creator. And it captivates and mesmerizes me, and I hope you.

When I consider your heavens and the works of your fingers, the moon and the stars that you have set in place… O Lord, our Lord, how majestic is your name in all the earth! (Psalm 8: 3, 9)
~~ RGM, July 30, 2019

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