Tyler Welton-Stewart: Epitaph for a Collapsing Star (2021)
Updated: Nov 4, 2021
I am absolutely thrilled to announce my new work for Clarinet and Strings, written for dear friend and colleague Laoise Kavanagh. I have wanted to write an intimate piece for the clarinet for so long and this provided the perfect opportunity. The clarinet is famous for it's rich, lush tone, and an expert player can tap into so many wonderful colours.
Epitaph for a Collapsing Star is written as an elegy for the great lights in the sky. Billions of years old, stars are born and die slowly, some fading gently into the the caliginous void of space while others burning up and exploding in a stunning display of light.
Having always been interested in space - I often wondered what happens to these stars: do they live forever?
Due to this stretched out life span of these stars so much is still theoretical, but what is certain is that there is a continual reliance on energy, a balance between this energy and gravity, and - in the case of massive stars - the eventual collapse and explosion, giving birth to supernova remnants and allowing the process to begin again.
Stars are born from clouds of interstellar matter which inevitably collapse and the enormous heat from this compression causes atoms to fuse together. The core of these stars is a swirl of pressure treated gasses which are constantly battling to remain balanced. These newly born stars have a fuel supply of hydrogen which exerts radiation pressure to keep gravity at bay. Eventually this hydrogen fuel burns off and - in the case of giant stars - can explode dramatically in a supernova.
When we see a star - including our sun - we are watching it as it burns hydrogen in it's core. This creates heat which is sent out into the universe. This is why we feel warmth during the day - we are feeling the star's radiating energy.
These stars ultimately begin to swell, and shed their outer layers. When a star is starved of energy, it collapses in on itself and tries to use up it's remaining resources to create different heavier materials. These dying stars grow larger, and the light pulses due to the star's growing instability. From here the star is doing everything it can to keep itself "alive." The star will continue to create these materials until it reaches one point - the creation of iron. Once the stellar core turns to iron, it lacks the ability to burn anymore, resulting in a true collapse. Due to the intense gravitational pull, these stars can shrink from the size of our Earth, to just a few miles wide! The core continues to heat to billions of degrees, before ultimately exploding in a supernova. This explosion blasts out all the material into space. Eventually - this matter will fuse to create new stars - new suns, new planets. An awe inspiring example of recycling, and rebirth.
This is a mosaic image, one of the largest ever taken by NASA's Hubble Space Telescope, of the Crab Nebula, a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers recorded this violent event in 1054 CE, as did, almost certainly, Native Americans. The orange filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the centre of the nebula is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The Crab Nebula derived its name from its appearance in a drawing made by Irish astronomer Lord Rosse in 1844, using a 36-inch telescope. (NASA, ESA, J. Hester and A. Loll (Arizona State University)
Wispy tendrils of hot dust and gas glow brightly in this ultraviolet image of the Cygnus Loop Nebula, taken by NASA’s Galaxy Evolution Explorer. The nebula lies about 1,500 light-years away, and is a supernova remnant, left over from a massive stellar explosion that occurred 5,000-8,000 years ago. The Cygnus Loop extends more than three times the size of the full moon in the night sky, and is tucked next to one of the 'swan’s wings' in the constellation of Cygnus. (NASA/JPL-Caltech)
In the Crab Nebula, a rapidly rotating neutron star, or pulsar (white dot near the center), powers the dramatic activity seen by Chandra. The inner X-ray ring is thought to be a shock wave that marks the boundary between the surrounding nebula and the flow of matter and antimatter particles from the pulsar. Energetic particles move outward to brighten the outer ring and produce an extended X-ray glow. The jets perpendicular to the ring are due to matter and antimatter particles spewing out from the poles of the pulsar. The fingers, loops and bays visible on the outer boundary of the nebula are likely caused by confinement of the high-energy particles by magnetic forces. (Chandra X-ray Observatory)
The Crab Nebula, which contains the Crab Pulsar (the red star in the center). Image combines optical data from Hubble (in red) and X-ray images from Chandra (in blue). (NASA/CXC/ASU/J. Hester et al)
The music begins with a birth of a star: sustained first violins and cellos providing the body of the stellar nursery as it undergoes gravitational collapse, while the undulating second violins and violas convey the swirling gasses and dust. Pushing and pulling, this chaotic amalgamation is told through dissonances in the strings.
The strings quickly come together for the second theme as the pressure and temperature rises:
This theme is continuously restated in various voices, gently reformed, portraying the creation of tens of thousands of stars formed in embedded clusters - a body of stars still surrounded by their progenitor stellar nursery.
Eventually the theme is refocussed as thermonuclear fusion occurs and what remains is an open cluster of stars:
We have our gleaming star: majestic, noble, a stunning product of immense turmoil. The clarinet solo appears for the first time as the embodiment of this star, confidently fuelled by an abundance of hydrogen.
This star burns bright, gleaming with an immense light. A held high E with harmonic strings portray this blinding light:
Thus begins a life of aeons, floating alone in space, slowly depleting fuel. The clarinet gently floats up a fifth each time with a crescendo symbolising the light it radiates at the expense of its hydrogen:
After a long life, what would take millions of years is conveyed in a matter of seconds as the star burns the last of its hydrogen and the process of gravitational collapse begin. The clarinet releases an anguished cry on a high A, as the strings climb in suspension before expiring in a shimmering D major 9th chord, pushing up into Esus4:
After the hydrogen-helium fusion, the star begins to swell. At this point the core is primarily carbon and oxygen, the carbon then ignites and fuses to create other elements. Desperately clinging to life with a core becoming largely made up of iron, the clarinet fights a losing battle. With rising and falling strings characterising the outer layers of the core stripping away, the clarinet gives one last cry as the core collapses, unable to support itself - releasing a powerful supernova:
We hear the second theme again, filled with anguish as the supernova tears across space in a shock wave:
As the supernova remnants push and spread matter into far reaches of space, the first theme is restated, this time with the viola line also re-interpreted by the clarinet, foreshadowing the new beginning of the stellar cycle:
After a cadenza from the clarinet, the music modulates into E-flat major, a key I find to be deeply comforting and warm. Lyrical and gentle, this finale conveys the birth of a new stellar nursery. After such chaos and division, matter comes together one again, and the cycle continues.
The two prominent themes come together for the first time as theme one is played the lower strings, with the second theme being played by the violins. The solo clarinet floats above these, binding them together. The piece ends with a C minor chord with an added second, providing an unresolved end, reminding us that this process is cyclical:
Writing this piece was a true marriage of my two passions - composition and research. So much of my research is spent specialising in historical musicology, particularly that of vocal music. Branching out into something new was really exciting, and proved a substantial challenge. I don't think I'll be getting into astrophysics anytime soon though! I hope you as the listener - and performers too - can look at this piece now as more than just dots on a page, and see an overarching story. Stars are born and die over periods of time that are simply intangible to us humans. With this piece I hoped to bring the process a bit more "down to Earth" as it were, and condense it.
If you made it this far, I truly thank you.
- Tyler Welton-Stewart
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