Author Topic: Inner Sphere in context  (Read 280 times)


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Inner Sphere in context
« on: 03 October 2017, 02:46:44 »
University of Chicago archives had the following dusty images, of everything within 500pc = 1700ly of Earth, which I annotated to situate the BT Universe in galactic context:

Please do note that the academic image follows the scientific community's galactic coordinate system, which is actually "left handed".  Makes life slightly more difficult, please consider the captions.

Most if the Inner Sphere resides in the vast "Local Bubble", a largely evacuated region of the Interstellar Medium (ISM) wherein the space plasma is hotter and more rarified (less dense) than average.  That makes night skies comparably bright and full of twinkling stars as far as the telescope can see. 

However, the Coreward Periphery of Kurita space extends into the outskirts of the Aquila Rift, a dense molecular cloud whose higher particle density would tend to obscure & redden distant starlight (basically the "sunset effect" on Earth, whereon dust in the atmosphere scatters waning dusk sunlight, preferentially the blue wavelengths, so dimming & reddening the sky).  This would plausibly make night skies on such worlds darker & redder than elsewhere, with "fewer stars all less visible".  Maybe gives writers some ideas for story settings?

Also note that, perfectly plausibly, the "Outworlds Wastes" stretch Spinward into a long "Spinward-stretching finger" of the Local Bubble, as if it were easier to detect and hence reach the viable star systems there.  And one may note that the "Exodus path" of the pre-Clan SLDF wound its way Spinward & Coreward from Kurita space, "around & behind" the dense Aquila Rift cloud.  The Caliban Nebula ("cn" on the map) appears to be a dense "compression" nebula "swept up" by the expanding "Scorpius-Centaurus Shells", i.e. shock-fronts sweeping through the ISM from ancient Supernovae (SNe).  Likewise, the Clan Homeworlds ("CH" on the map) reside in a denser & cooler region of the ISM, on the "farside outskirts" of the Aquila Rift.  Like Coreward Kurita space, the night skies would probably be dimmer & redder than those of the IS, e.g. Earth, further obscuring & hiding the CHs from the IS.

The Hanseatic League & Neuva Castile ("HL" & "nc" on the map) appear to reside within dense molecular clouds.

The SNe shockfront "shells" sweeping outwards from the Sco-Cen association & Orion star-forming regions contain high levels of radioactive Iron-60.  The "Orion shell" may have been generated by an ancient SN several hundred thousand years ago, whose compact neutron star remnant now careens through the galactic disk (from near the Orion star forming region, in a generally Spinward direction) as the Geminga Pulsar ("G" on the map).  More space trivia, maybe even useful :) 
« Last Edit: 03 October 2017, 02:49:56 by Thunderbolt »


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Re: Inner Sphere in context
« Reply #1 on: 10 October 2017, 11:58:48 »
IS looking "down" from N galactic pole

Map, scaled and reflected, of the IS situated in the "Local Bubble", as viewed from high "above" the plane of the galactic disk.  Shading shows "column density" of space gas & dust "projected" onto the disk plane of the Sun's orbit around the galactic center.  "Vertical" (z-axis) information is "projected out".  The figure includes the UMa (trivia: most of the stars of the Big Dipper) and Hyades in CC space, as well as the (projections of the) spherical "shock front" shells sweeping outward from the Scorpius-Centaurus star-forming regions arcing around the periphery of the LC:

possible game FX: the high-density (10x the Local Bubble average, ~0.5/cm3) of gas & dust swept up into the fast-moving shock fronts (~100km/s relative velocity) is "clumpy" with dense "cloud cores" 1-100AU across which can & do overwhelm stars' winds to penetrate into their inner planetary systems, without being disrupted or dispersed.  There they can & evidently have obscured the central star, and deposited material onto inner planets, for hours to days to weeks or more.

A high-velocity core passing through an IS star system would resemble the 21st century movie Gravity, acting like a giant shotgun blasting planets, moons, travelling dropships, and recharging jumpships with high-velocity microscopic debris.  This could affect all manner of orbital & space-transport-dependent BT operations, grounding dropships and endangering all space-based assets, for protracted periods.

This could account for why the IS, more than less, appears to abut the boundaries of the Local Bubble, without penetrating past its walls.  First, the higher densities of dust & gas beyond obscure observations of any star systems secreted amidst the same, making measurement of distances & determinations of precise locations difficult.  Moreover, the possible presence of transient mass anomalies near those stars further complicates Jump-point positioning & Hyperspace Jump calculations.

As above, but with an added contour, showing the intersection of the "wall" of the "Local Bubble" (where the density of space gas & dust increases sharply) with the Sun's orbital plane.  Almost invariably, anywhere & everywhere where the shading extends "Sun-ward" beyond & inside of the contour, represents concentrations of space gas & dust below the plane of the picture:

IS looking "forward" along Sun's direction of motion from anti-spinward

Our Local Bubble forms a "chimney" penetrating through the galactic disk and opening out into the galactic halo both "above" and "below" the disk.  The Local Chimney angles "up and away" from the galactic center (towards the N galactic pole [+z] and rimward [-x]).  From the anti-spinward vantage point, the LC & FWL are visible,  coreward (+x) and rimward (-x), respectively.  Their depicted radius is the usual & customary 400 lyr ~ 122 pc.

As above, the shading shows projected column density, and the contour shows the intersection of the Local Bubble wall with the plane (x,z) of the picture.  On the left side of the image, wherever the shading extends beyond the contour represents material "beyond" the plane of the picture, i.e. farther spinward (y>0).

Crude sketch of the "verticality" of the IS, to swiftly suggest the extra "degree of freedom" available to writers, GMs, et al:

possible game FX: Adding another axis ("z") along which IS star systems could have differing positions would tend to increase the distance between them.  "Stretching" the IS "vertically" would make the IS rather sparsely populated, such that inhabited star systems are few & far between

However, as of the 31st-32nd centuries, only one in a thousand star systems are settled.  So, in amongst the systems typically displayed on IS star charts, drift a thousand times as many others, whose otherwise typical stars do not happen to harbor viable worlds suitable for settlement.

This suggests the notion of "transit systems", non-inhabited IS star systems used as "KF-drive recharging stations" en route between inhabited ones.  Notable Jumpship pilots may have accumulated centuries-worth of Jump-point data for their favorite selection of systems, as well as Hyperspace Jump calculations for transits between them.

Some of those transit systems may harbor "marginally habitable" worlds which once were tentatively settled during the heyday of the Star League, but whose colonies collapsed in the centuries since.  Such sites could conceal Lostech.

Note that Periphery powers probably extend as far in the "vertical" direction (z) as they do in the primary galactic disk plane.  If so, even major Periphery powers, like the Taurian Concordant (depicted in dark orange) and Magistropy of Cassiopeia (depicted in light green), would be dwarfed by the major IS states.  Note, too, that both the Taurian Concordant & Magistropy of Cassiopeia would have breathtakingly beautiful night skies, by virtue of being located near to the panoply of OB star-forming regions in Taurus, Auriga, Perseus & Cassiopeia.

IS looking "outward" from the galactic core

The Local Bubble is actually more like a "crater" which narrows in the "downward" direction, i.e. towards the S galactic pole (-z).  Here, viewed from the galactic core (or Clan homeworlds), the LC & DC are visible, anti-spinward & spinward, respectively. 


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Re: Inner Sphere in context
« Reply #2 on: 10 October 2017, 16:38:34 »
This is a brilliant layout and thank you for doing this!
Ghost Bears: Cute and cuddly. Until you remember its a BLOODY BEAR!


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Re: Inner Sphere in context
« Reply #3 on: 11 October 2017, 06:36:50 »
Thanks for the thanks :)

I've been trusting the outputs of the NED coordinate converter.  Very frustrating if you're not used to the required input format:
  • Generally, you have to set everything to "J2000.0" instead of "B1950.0" -- including the "observation epoch" on the second hand which must be typed manually
  • the required format for starting coordinate values
    • Right Ascension (RA) = "12h 34m 56s" (hours / minutes of arc / seconds of arc)
    • Declination (Dec) = "-78d 54m 32s" (+/- degrees / minutes of arc / seconds of arc, and need to use the regular "-" character, notably not Wikipedia's "−" (emdash??) character
Astronomy helps understand BT universe history, e.g. the hundred year concealment of the Rim World's Republic from the IS... "behind" the blazingly bright Sco-Cen star-forming regions as well as one of the dense shock-front shells emanating from them and bulldozing into the surrounding molecular clouds just "beyond" the peripheral marches of Steiner space.  Just one example, another being that the SL-era OWA deep-periphery settlements extend naturally into the "finger" or "tunnel" jutting spinward from the Local Bubble, also viewable on the maps above, all meshes up :)


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Re: Inner Sphere in context
« Reply #4 on: 12 October 2017, 08:43:05 »
Very cool. I'll need to give it a closer look later when I get the time.