THE SOUTHWORTH PLANETARIUM

207-780-4249   www.usm.maine.edu/planet

70 Falmouth Street   Portland, Maine 04103

43.6667° N                   70.2667° W 

Altitude:  10 feet below sea level

Founded January 1970
Julian Date: 2458829.16

2019-2020:  LXIX

                "Hey, why did the surrealist cross the road?"

                "Why?"
                "Lemon."

THE DAILY ASTRONOMER

Wednesday, December 11, 2019

At the Tip of the Sagittarius Stream

...a solitary creature looks expectantly  toward its eastern horizon  From our perspective he appears quite monstrous:  a bulging eye forming an equilateral triangle with two recessed eyes below.   Protruding from its curved back a self-luminescent dorsal fin points spire like toward a sky black as pitch.   The glow he exudes allows us to barely see swirls of his exhalation vapors that resemble smoke billowing around a neon green light.     He doesn't cut a particularly appealing figure.    Of course -no offense- he would be similarly repulsed by us.   Not that he'll ever see us.   He's thousands of light years away and, besides, from his time frame, we've all been dead for about 170,000 years..

He jerks his head up as a meteor slices across the unbunded abyss above:  one in which stars are few, faint and far between.   His mood, at first dour owing to the early hour, becomes hopeful.    He scans the landscape dappled by many other luminescent figures scattered in all directions.    The glowing figures are showing sudden pulsations: unmistakable signs of building excitement.    Another brilliant meteor, one with a persistent train that leaves a slowly dissolving phantom trail in its wave, heightens the tension.    The three that quickly follow within the next few moments are greeted with a blaze of blinking lights stretching apparently ad infinitum.     The crowds are growing rapidly.

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Now the stupid DA is going to interrupt:

Hello!  My apologies.    You've been listening (or reading) a transmission from the Pantheitkeran mechanism.  We've installed it around the perimeter of our  star dome.   Imagine the frequency spectrum as found on your radio, except we have 17 of them: each one wrapped around the dome circumference, one atop another.   Each spectrum consists of  196611 settings.    (I gather that both 17 and 196611 represent

two of the 31 known odd-sided constructible polygons and for some reason that matters with this mechanism.)  Each setting offers a different view on some point in space-time that appears in full dome clarity on our dome.  For instance -yes, I know you've fallen asleep- imagine that on strip Alpha I aligned point 10,235 with point 8,345 on strip Beta while the other strips remain in the neutral position. (Of course we pretentious twerps used Greek lettering.) That would show me a certain space-time point. (a dazzling cityscape on a sultry desert world somewhere in the galaxy NGC 3982 about 1.7 million years ago.)   Now, if I maintained the two upper positions and shifted the Zeta spectrum so that the point 1,893 aligned with the points in strip one and two, I would watch another ST point (That time it was just a convex eye glowering furiously back at me somewhere in one of the 509 globular clusters surrounding the Andromeda  Galaxy 310 years from now, so, yippie, I've made a new friend.)*

If I weren't such a mathematical fool, I could tell you how many possible settings exist.   

At the beginning of this article, you were reading about a bio-luminescent species living on a planet revolving around a star at the very tip of the Sagittarius Star Stream. See the image above.  Our friends are perched literally at the "top" of this stream.  It was produced by the tidal forces the Milky Way Galaxy exerted on the Sagittarius Dwarf Elliptical Galaxy.  These polar loops consist of stars stripped away from this dwarf galaxy.   Over the course of more than a billion years, these stars will eventually become incorporated into our galaxy.  Now, they are moving rapidly like chairs on a ferris wheel up and around the Milky Way.

We've been watching them marking the "Arrival of the Lights."   (We can't hear them, of course, and wouldn't have the faintest idea about their language anyway.  So the "Arrival of the Lights" is our description of this event.)     Their planet revolves around a wide orbit centred on an F-type star that is more luminous than the Sun.  Consequently, its distance is greater and year correspondingly longer than ours.   At a certain point in its orbit, the dark side of the planet is directed toward the unbounded black void of intergalactic space.   However, as it moves toward its equinox point, the planet maneuvers around toward the clusters of stars comprising the stream arc.       The night sky, which is very dark apart from a smattering of renegade stars** hurling away from the stream, becomes a spectacle of brilliant lights as the planet moves toward the stream.  

In their late winter, the creatures watch for the first of these stars to emerge above the eastern horizon before the dawn twilight obscures them.     (As they are at a high latitude, the rise of their parent star is slow, affording them the opportunity to watch the stars for many moments before morning)   In their summer, the night side of the planet is fully immersed in the nearly pervasive radiance of the star stream:  enough to cast a luster onto the nightscapes comparable to that we see here under full moonlight.)    We here in the Orion Cygnus Arm can't imagine seeing by starlight.    

Sorry for this interruption.    Let's go back.

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The landscape seems as though it is being swept with a wild fire of flickering emerald as the throngs of creatures exult in the appearance of two brilliant stars above the slowly intensifying twilight.  They are joined by a veritable fireworks display of meteors from their most prominent shower, which just happens to correspond to the arrival of the lights.      

Within a minute the festivities reach a climax as a fire opal star peeks above the horizon.   In response, all the creatures gathered in their hundreds along the landscape arc their faces skyward and welcome the star with furious belches of flame.        The new season has begun.

Please don't judge them too harshly.  Imagine their reaction if they could see how we behave....or how we did behave more than a hundred thousand years in their past.

*Yes, you're right.   Considering the size of our dome, the width of each spectrum is small and the numbers so ludicrously small that we need special high powered microscope spectacles to see them.     And, no, we actually don't go to these places (That would be impossible.)  We merely look onto them.

**At the setting  Alpha   3,988   Beta 112,183,   Gamma 668   Eta  14,365   Theta 111 one can see the first beast drawn wagons in a prairie town on a world around one of these flying stars in 96,014 AD

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