…on the outer edge of a spiral galaxy, home to a hundred billion stars…
…a star died.
This was no ordinary star. It was a monster of a star, at least 20 times more massive than our Sun.
Because of its enormous mass, the temperatures and pressures at its core were insanely high. Through a chain of violent nuclear fusion reactions, this star exhausted the hydrogen fuel in its core in less than a thousandth the time that a star like our Sun would require to consume its core hydrogen.
So furious was the pace of this star’s consumption of its core hydrogen that in its prime it shone 10,000 times more brightly than our Sun.
But you know the saying, “Live hard – die young.”
And oh, how this star died.
When a star with 20 times the mass of our Sun dies, it blasts itself into oblivion as a “Type II supernova,” the most spectacular and violent explosion known in the universe.
A Type II supernova is a rare event. Even in a large galaxy containing more than 100 billion stars, this type of supernova occurs roughly once every hundred years.
The energy released by this supernova is almost incomprehensible. For a few weeks or months the dying star can radiate as much energy as the combined output of all the other stars in its galaxy.
Countless photons (sub-atomic packets of energy) from this supernova blazed outward at the speed of light. They zoomed through the interstellar regions of its galaxy for thousands of years before finally clearing the galaxy and embarking on a journey through the greatest voids known to science – intergalactic space.
For more than twenty million years, a small cohort of these photons raced in one particular direction through the frigid, empty darkness.
As time passed some of the photons collided with rare, random, microscopic flecks of intergalactic dust, and ceased to exist.
Most of the photons, however, screamed onward through the emptiness at 300,000 kilometers per second, eon after eon.
For a tiny portion of these photons, a spiral galaxy, our Milky Way galaxy, loomed ever-larger before them.
This particular stream of supernova photons, having spent more than 20 million years in flight, first encountered the borders of our galaxy as early humans were beginning to domesticate dogs and invent agriculture.
For ten thousand years the photons penetrated ever deeper into our galaxy. A vanishingly small fraction of them were bound for a solar system dominated by a medium-sized and middle-aged yellow-white star, located on the inside edge of one of the large spiral arms of the Milky Way, about thirty thousand light-years from the galaxy’s center.
Of these photons, a still smaller fraction headed in the direction of that solar system’s third planet, a pretty little blue and white world in possession of liquid water oceans and a significant atmosphere.
And of those photons an even tinier fraction were heading for the western United States, and found themselves hurtling toward Garfield County, Utah.
A trickle of these photons were destined to meet their demise on a summer evening within the boundaries of Bryce Canyon National Park.
And of this tiny trickle of photons, an infinitesimal portion of them would conclude their 20 million year trek not in an ignominious collision with the rocks and trees of Bryce Canyon, but instead they were intercepted and reflected by carefully shaped mirrors, ricocheted through prisms, and refracted by small pieces of precision-ground glass.
The final two inches of these photons’ intergalactic travels were even stranger: They encountered the living cells of the cornea and the focusing lenses of human eyes, abruptly ending their long journey by impacting the highly evolved photoreceptive cells of the retina and creating a cascade of neural signals that moved along the visual cortex and into the brain.
Brain cells then rapidly processed the stream of blended electrochemical impulses into a perception of a dim, swirling spiral galaxy of stars, the famous “Whirlpool Galaxy,” notable on this night for the appearance of a singular, dying star that had only recently become visible.
These photons had traveled for more than 20 million years to make their way into more than fifty telescopes (one of them mine) that were participating in the June 29 – July 2, 2011 Bryce Canyon “Astrofest.” This was an annual gathering of volunteer amateur astronomers sharing their love of a pollution-free nighttime sky and their desire that the public should appreciate it better.
Swarming around those telescopes, each guided by good people from the Salt Lake Astronomical Society, Bryce Canyon National Park, Clark Planetarium and other astronomy-loving organizations, were an estimated five thousand park visitors from across the globe who were discovering that the nighttime skies in Bryce could be as spectacular as the daytime views of its unusual geology.
We were not looking at photons emitted by a TV or computer monitor, or bounced off the ink on the glossy page of an astronomy magazine, but the actual photons emitted by a massive dying star from a long time ago in a galaxy far, far away.
We saw that with our own eyes. Amazing.