Neowise – flight of the cosmic moth
Comet NEOWISE C/2020 F3 in the skies above northern Saskatchewan. Photo by Tero Patana/iStock/Getty Images
The night sky was a dance floor, polished lapis lazuli scuffed by the soles of three pairs: in the west, Saturn and Jupiter had come to the party as a couple but were practicing prudent social distancing. Eastward, Venus and Aldebaran were dancing cheek-to-cheek. South, the odd couple of Mars and Moon were about to split up: Luna heading east, leaving the god of war in the dust of her glow.
But the main attraction was Comet NEOWISE C/2020 F3, a spray of mist low in the northeast, intruding on constellation Auriga’s locals like a tinhorn in a boondock saloon. A shallow dome of burnt gold stained the sky above the Sierra Nevada Range; the comet would soon disappear behind the swell of solar glare.
It was July 11, 2020. I stood on Round Valley’s topmost hill after a 1-mile, 1,000-foot climb through the shadows of blue oaks, the trail clarified sporadically by lunar light. The climb was dark but I deserved no sympathy. Those who find themselves alone in the dark should take consolation in the lives of comets.
If the orbit of planet Earth resembles a wedding band, the orbit of Comet Neowise resembles a rubber band stretched to the snapping point; the comet’s current orbit will extend 66 trillion miles into the hinterlands of our solar system. The astronomers of ancient Greece named the satellites of our Sun planetai, wanderers. Had their science been more advanced, they’d have applied the metaphor to comets. Neptune, the remotest of the wanderers, traces its ellipse around our Sun once every 165 years. Comet Neowise won’t return till A.D. 8700.
I stood on the hilltop, gaze fixed low on the northeast. No voice of bird or mammal broke the silence. I was alone in a dark and remote place but compared to the long loneliness of Neowise, my isolation was trivial. Like a moth from myth, the comet had flown from a desolation beyond fathoming toward a flame of gold, condemned to careen around that flame, be flung back into the frozen night, wander there for thousands of years and repeat the ordeal for thousands more.
The comet flaunts its blue ion tail and golden dust tail. Photo from Getty Images.
On July 3 Neowise, having cut inside Mercury’s orbit, made its closest pass by the Sun at a distance of 27 million miles, boomeranging around our star at 48 miles per second. Eight days later, as I watched it recede like a ship on the horizon, its sails billowing in the gale of solar wind, I strained to grasp what I was looking at. A mere 80 million miles away, a 3-mile-wide chunk of ice and dirt was escaping Sol’s gravity well like a cutter escaping a maelstrom. Neowise makes its closest pass by Earth today, July 23 at a distance of 64 million miles, having slowed to a mere 27 miles per second.
Weeks earlier, as the Sun’s heat caused Neowise to begin its transformation from chrysalis to adult, tails began to form. After tumbling unseen through the void for thousands of years, the latent light of Neowise was finally kindled. The first tail, tinged blue and streaming straight back, was made of ions and gas. The second, the dust tail, estimated at more than 10 million miles long, was golden and diffuse. On July 13, a rare sodium tail – exuding the yellowish hue we see in sodium vapor streetlamps – was detected. As Neowise flew off, the Sun’s coronal mass ejections and plasma waves caused the comet’s dust tail to develop synchronized bands not seen since Comet McNaught in 2006. Neowise had become a rockstar.
For millennia, comets have been construed as portents of disaster: the death of monarchs and fall of empires. Comets are unnervingly unlike most celestial phenomena. The routes of planets in the night sky have long been plotted. The gloom of a solar eclipse or flamboyance of a meteor shower – those spectacles occur at consistent intervals; their comings and goings can be predicted. But comets come out of nowhere, emerging wraithlike in the hovering darkness. Despite our astronomical savvy, no one can predict which iceball in the Oort Cloud’s rubble will get sideswiped into our Sun’s gravity well and intersect humanity’s 21st century. No one saw Neowise coming.
Evening of July 21 – time to say goodbye. I reached my sanctuary atop Round Valley’s northern hills in time for the setting of Sun and Moon, and rising of a fierce southwest wind. I tightened the drawstring of my hat.
Moonset over North Peak, Mt. Diablo State Park. July 21, 2020.
As night fell I trained my gaze on the sky below the Big Dipper – on a spot slightly west of a line from Megrez through Merak – and strained to resolve the comet through air dense with wildfire particulates and light pollution. Around 9:30 Neowise appeared, in the exact spot it was meant to be, like a wisp of fog, moth soft, drifting through a streetlamp’s gauzy glow.
When Neowise returns in A.D. 8700, who will see it? What manner of Earth civilization will turn its gaze skyward? Will Homo sapiens have abandoned the planet, or vice versa? Or does the comet herald a doom more imminent: the self-extinction of entities – though 7 billion souls strong – as infinitesimal in the scale and story of the cosmos as their infinitesimal blue world.
I turned my gaze away, west past the amassed black of Mt. Diablo, then southeast, where a light glared from a puncture in the sheet metal of night as if heaven were blazing behind it – the planet Jupiter. From behind the Vaqueros Hills rose a faint glow, the melded radiance of street lamps and homes in distant Livermore; sign of a species that has fought darkness from the beginning; illuminated caves and continents, resisted night as it resists mortality. I cinched my pack tight and took one last look at Comet Neowise fluttering away. I knew I wouldn’t see it again.
But on the way down, back in the shadows of oaks, just before the silhouette of foreground hills obliterated the heavens, I came on a clearing and looked up. The sky had darkened and the comet brightened. There we were – lone wanderers in the dark – in the exact spot we were meant to be.