Reclined beneath a ceiling of stars, at the foot of a tree that matured long before the time of Christ, it’s pretty difficult to feel important. That sense of awe is why I love making images that juxtapose the ancient bristlecones against the Milky Way. But, with a 40% moon parked in Sagittarius and completely washing out the brilliant galactic center, I had other plans for this chilly autumn evening. Instead of setting up for the view of the southern sky, I circled the tree to put my back to the Milky Way and the moon, and pointed my camera north. Now, with the north celestial pole in my frame, I was ready for a long exposure of the sky above the old bristlecone, using moonlight to illuminate the tree and turn the stars into parallel arcs surrounding the north star.
While counting down my 31 minute exposure, I zipped my coat and studied the bristlecone’s gnarled trunk and twisted branches, thinking of all the history that has unfolded in the several millennia it has spent earning its scars. But “history” is far broader than our earthbound perspective. In fact, to the stars I captured in this image, the 31 minutes of photons each delivered to my sensor where completely different than 31 minutes that I spent waiting for my exposure to complete. For example, the light striking my sensor from Polaris (the North Star) originated during a 31 minute span sometime in American colonial time (there’s some uncertainty about the distance of Polaris, but it’s probably 400 light years away, give or take 50 or so years). And even the light from the closest stars is a few years old, while the most distant starlight in my frame is older than this tree.
Star trails are a great example of the camera’s ability to reveal aspects of the natural world missed by our “right now” human bias. From this narrow perspective, at any given time the Universe appears fixed. But observing the night sky for a few hours, you soon realize much more is going on. Those apparently stationary points of light overhead all follow the same east to west arc across the celestial sphere, ultimately disappearing beneath the horizon, or behind the glow of daylight. Most return to nearly the same place twenty-four hours later, but a few noticeably shift relative to the stellar background. For millennia, explaining these wanderers—the planets—while maintaining our perceived position at the center of the Universe required convoluted solutions that defied scientific scrutiny. Then Copernicus, in one elegantly simple paradigm shift, removed Earth from the center of the universe and set us spinning about the Sun, pouring the foundation for humankind’s understanding of our place in the Universe. The humbling truth is that we inhabit a small planet, orbiting an ordinary star, on the outskirts of an average galaxy.
Thanks to Copernicus, Galileo, and others who followed, we now take for granted that Earth revolves about the sun, secured by gravity’s invisible string. And while it appears that our star-scape spins above our heads, it’s actually you and me and our seven-plus billion Earth-bound neighbors who are spinning. Locked into our terrestrial frame of reference, distracted by the problems of life, we stay generally oblivious to the celestial dance overhead. But I can think of no better way to get some perspective on our place in the universe than to look skyward on a dark night, far from city lights.