I rotate around the sun
not really climbing
to an orbital wave
that rises gracefully
and twirls among the stars.
A Comet's Tale originated from early discussions with Emily Ferrell about a release with the Subterranean Tide label. I had mentioned that I always wanted to do a release based around my interests in astronomy and a day later Emily came back with the evocative poem that graces the cover art. That poem directly triggered the idea of following the path of a comet from its origins in the distant Oort Cloud of our outer solar system, to it's perilous journey past our Sun and return home, if it survives!
A comet is basically a large boulder-like mass of ice, gas and dust, which closely resembles the smaller rocky asteroids in form. Very slight gravitational forces from nearby stars, including the Sun, can pull these objects out of their normal orbit and onto a new path which sends them careering into our solar system. The Oort Cloud is the most distant home of comets and forms a sort of spherical shell of objects orbiting our solar system way out beyond Neptune. The musical journey follows a typical long-period comet (a comet that takes more than 200 years to complete it's orbit), which has been dislodged from the Oort Cloud and is on an incoming trajectory around our Sun. Aphelion is when our comet is at it's furthest point from the Sun, coasting in through the outer solar system, it's dust tail streaming majestically behind it and increasing in speed all the time. As it reaches it's point of closest approach to the Sun, or Perhelion, the speed picks up and the comet faces it's most dangerous time buffeted by the solar wind and in a constant tug-o-war with the powerful gravitational pull of the Sun. A special group of comets, the Sungrazer's, are the adrenaline junkies of the comet world and either survive, or die by evaporation, as they skim close to the Suns upper atmosphere. If a comet survives this passage around the Sun and passes close to Earth on it's way back out to the Oort Cloud it can turn into one of the most spectacular objects seen in the night sky. The sun heats up the comet and triggers the expansion of internal gasses, which explode through the surface. The comet then goes into an outburst phase where it dramatically increases in size and brightness and becomes visible to us with small telescopes, binoculars or the naked eye. One of the common gasses vented is Cyanogen and this can give the comet's coma (head) and tail a lovely green hue. The dust left behind in the trail of an orbiting comet makes up most of the material we see as meteors flashing through the sky during a meteor shower as the dust burns up in our atmosphere. Many of the main meteor showers can be directly linked to a particular passing comet or asteroid. The comet then passes out of our visible range to return again in a few hundred, or perhaps thousands, of years and is therefore truly a once-in-a-lifetime object to see.
If you get a chance this winter do follow the story of Comet C/2012_S1 (ISON) as it becomes visible from November onward en.wikipedia.org/wiki/C/2012_S1
This is a newly discovered sungrazer comet which has the potential to be one of the most spectacular comets visible this century...if the Sun doesn't melt it!