Tonight, with clear weather and no moon around, I am up late to look at a dark sky with the first decent pair of binoculars I’ve ever owned. The vaguely textured white blur of the Milky Way that my eyes have long admired, unmagnified, now resolve through the 10x binoculars into clusters of countless stars with crisscrossing fuzzy ribbons of black woven in between.
I pan the circular field of view slowly along our galaxy’s long overhead arc, immersed in the depth I sense above me from my two eyes merging a single image. There’s a satisfying tangible connection between the fine motions of my arms and the slow sweeping past of this collection of a hundred billion stars in our little corner of the universe.
A dim smudge near Cassiopeia teases my eyes’ limits of sensitivity and resolution. I think it’s M52, a globular cluster a few thousand light-years away. It was first identified by Charles Messier in 1774. The photons I’m collecting in my binoculars tonight from its 193 or so stars were more than 90% of the way here when Messier peered through his telescope. In the meantime, a nation rose through a rebellion and then quashed one of its own; enslaved, freed, and still long oppressed a large fraction of its citizens; conquered its native peoples and then rescued others from conquest in two world wars.
These photons had already emerged from their nuclear furnaces by the time some settlements along the river Tiber formed the first humble beginnings of the Roman empire.3 Their journey may even have been halfway underway by then; we’re not sure exactly how far away M52 is from us.4
It’s been a little more than two thousand years ago since a citizen of that empire, a gifted poet and philosopher, stood next to some pool or pond beneath the night sky. The skies anywhere in Europe were darker than they are now, even at my place out in the country. I imagine Titus Lucretius Caras (c. 99-55 B.C.) looking at an image of the blazing array of stars overhead, seeing their “images,” which, he muses, must “be able to run through space incalculable / In a moment of time.”5
The pointpoints and patterns of the stars are mirrored in the still water before him, “not turned round intact, but flung straight back / In reverse,” with the features thus shown “in reverse.”6 He moves slightly to one side along the water’s edge and notices how one particularly bright star near the horizon comes abruptly into view from behind the tree. Its direct image and its reflection both wink on instantly–at exactly the same time, as far as he can tell.7
A smooth surface of water is exposed
To a clear sky at night, at once the stars
And constellations of the firmament
Shining serene make answer in the water.
Yet he knows that the “images” raining down from the sky take a longer route when they make the extra trip to the water and back than when they go directly into his eye.
Now do you see how in an instant the image
Falls from the edge of heaven
to the edge of earth?
Wherefore again and yet again I say
How marvellously swift the motion is
Of the bodies which strike our eyes
and make us see.8
Those image-bearing bodies are “marvelously swift” indeed. They move 186,000 miles–more than 23 earth diameters–through the vacuum of space every second. Yet the immense vault of our universe is so incomprehensibly vast that it’s taken most of the span of human civilization for them to reach us, from a relatively nearby neighbor within just our own galaxy (there are at least a hundred billion others).9
Silent and impassive to all the twitches and ripples in the microscopic biofilm of one ordinary planet, in the hundreds of years since Messier noticed this odd feature among the stars–in the thousands filled with death and wars and tears of joy and sorrow since Lucretius did his ancient poolside musings–the photons from its clustered stars continued their long journey outward. Only now do they finally land on my retinas to collapse wave functions and trigger individual rod-shaped cells to launch neurotransmitters down neighboring filaments of cell-strings along my optic nerves.
In my brain, a little smudge registers. Something’s really up there.
The stars in M52 will keep launching their photons all my life, as they have for 35 million years now. They’ll get lost in the sea of light that covers and warms the daylight half of earth, fall through clear skies over the other half in darkness, and remain ignored almost always, as the earth swings around its own little star a few dozen more times until my eyes no longer see anything at all.
And yet, despite my absence, the earth will stay in its orbit and the photons will stream on.
Notes
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Does it surprise you to see such ringing words of spirituality as the epigraph to an atheist’s essay? Such prose retains its profound beauty regardless of one’s disagreements with its message. And even with no God in the picture, I am still happy to call whatever was behind the Big Bang, or the quantum fluctuation that unleashed the Big Bang, or whatever was behind that, a “power that is unfathomably secret,” even holy, filling me with a sort of reverence as I gave upwards at night. ↩
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There’s also some light pollution near the horizon, even out here, miles from the nearest city. I’ve tried to de-emphasize it with reduced yellow and green luminance. ↩
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Because “this cluster is in the plane of the Milky Way,” our available “methods of determining distance are too uncertain,” some yielding estimates “as small as 3,000 light years, while others are as large as 7,000” (Ethan Siegel, “Messier Monday: A Star Cluster on the Bubble, M52,” ScienceBlogs. ↩
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Lucretius, Book IV, line 191. From On the Nature of the Universe, Ronald Melville, trans. (Oxford University Press). ↩
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Book IV, lines 295-99. ↩
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It’s not exactly the same time, of course, something I remain well aware of as an electrical engineer with a radio background. Indeed, engineers rely on the known and limited speed of light to do antenna design with all of its resonant and carefully spaced conductive elements. Quarter-wavelength spacings abound. ↩
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Book IV, lines 210-17. ↩
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“How Many Stars Are There In the Universe?”, European Space Agency. I’ve seen another dim smudge out there in the night sky from the nearest of those other galaxies, Andromeda. Its photons took millions of years to reach me instead of thousands. ↩
