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Astronomy in Pournelle's Future History

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Galactic Map

MAP: Milky Way Galaxy and the Empire of Man

This map of our galaxy (the "Milky Way") is based on the one in the 1994 Cambridge Atlas of Astronomy. All star positions are taken from the Gliese Catalog of Nearby Stars and various other catalogs.

Very few real astronomical objects are mentioned in Pournelle's Future History series:

Galactic latitude and longitude give an object's position from Earth's perspective. The core of the galaxy is at 0° latitude and 0° longitude, at a distance of around 30000 LY. Due "north" along the galactic axis is latitude +90°.

There are over 100 000 000 000 stars in the Milky Way Galaxy. The Core of the galaxy is an ellipsoid with 5000 LY as its vertical radius and 10000 LY as its horizontal radius. The entire galactic disk has a horizontal radius of 50000 LY; our sun is around 30000 LY from the center.

Thus, leaving Sol and heading through Sagittarius, it is 20000 LY to the edge of the Core and another 10000 to the galactic center; heading through Gemini it is around 20000 to the horizontal edge of the galaxy. But one can leave the galactic disk by heading "vertically" a mere 1500 LY.

Note from the map that our sun isn't actually in the local (Sagittarius) arm. But the spaces between the arms still contain stars. As David Gerrold once commented, trying to pinpoint the precise "edge" of the galaxy is like trying to bisect a sneeze. We will merely see a gradual increase in the distance between stars as we "leave" the galaxy.

The motion of stars in a galaxy is very odd – the stars rotate about the center of the galaxy at a much different rate than the spiral arms rotate! Think of the stars as cars, and the arms as "traffic jams" on a freeway – the speed at which the "jam" moves doesn't match the speed of any car. If you're interested in the details, take a look at Binney and Tremaine's Galactic Dynamics.

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Map of Known Stars

MAP: From Sol to the Coal Sack

This map shows Sol, 82 Eridani (Meiji), Acrux (Crucis?), and the Coal Sack. Their locations were already described above. The map's scale is correct with regard to these objects.

The additional stars on this map are not identified with any stars known today:

These distances aren't enough to triangulate the precise positions of these stars. But using these distances and the map in Gripping Hand, they can be plotted within a reasonable degree of error. Note that I have, for simplicity, assumed that these lie somewhat in a plane; by letting them move towards and away from the viewer (galactic north and south) the apparent map-distances could be reduced.

The "CoDominium 2090" border reflects the 200 light-year diameter of the CD mentioned on FL 297. More on this later.

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Map from Earth to Sparta

MAP: From Sol to Sparta

This map shows a closer view of the neighborhood of Sol. The scale of this map is speculation, other than the distance from Sol to 82 Eridani.

The tricky part lies in the fact that Alderson jumps are of varying size. Sparta is six jumps (and six or seven months) from Earth, and Tanith is one jump and one month from Earth (for sources, see below). Meiji is 20 LY from Earth, and (by the ideal route) only two jumps. As a reference for comparison, we may note that (elsewhere in the galaxy) Prince Samual's World and Makassar are 12 LY apart and only one jump apart.

So I've allowed around 10 to 15 LY to each jump on this map, although this is clearly not going to be always the case. (According to WWPW 34, as of 2091 the longest jump ever acheived was 42 LY, and the context makes it clear this was an unusually long jump.)

Green lines represent single jumps. Blue lines represent one or more jumps: this simply means there is a fairly direct "route" between these two stars, but the number of jumps is unknown.

The usual route from Meiji to Earth involves several jumps and passes by Colby. The "direct" route involved exactly two jumps, stopping off at A-7820 (presumably a red dwarf or other uninteresting star) on the way. ("He Fell into a Dark Hole" 18, 21, 24)

The stops from Earth to Sparta are explicitly given on GTS 149 (Prince 717).

Tanith is on the standard routes from Sparta to Earth and from Sparta to New Washington. (See below for more details on New Washington's location). Coming from the Earth, the worlds of Haven, Frystaat, and Dayan are "beyond Sparta". (GTS 94, 149; Prince 679, 717) Crucis is probably also in this direction, since Dayan (later known as Dyan) is in Crucis Sector. (WWI 362)

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  Distances and travel times

There are frequent mentions of travel times and distances in the Future History books. For the most part they are consistent. This allows us to categorize planets based on their proximity to Earth.

In what follows, all travel times are for normal transit during the 21st century unless otherwise specified. The fastest military ships can sometimes cut these travel times in half (PS 166; Prince 986; WWJ 192) due to their faster speed, and due to the fact that ordinary ships must choose a route that passes near refueling stations, whereas certain military ships get more light-years to the tank (Prince 975). It is also stated that "the fastest messages" can travel in half the time (PS 8; Prince 870) -- but this seems too slow, for a series of messaging lasers sent between small ships stationed next to Alderson Points could be extremely quick, and this would explain how the messages about the "Rump Senate" coup travel from Earth to Sparta in a mere two months (March to May 2096).

The following worlds are relatively close to Earth. All of them were settled during the 21st century.

The following worlds are a medium distance from Earth. All of them were settled during the 21st century.

The following are among the farthest colony worlds settled during the 21st century.

The following worlds were settled during the First Empire, and lie beyond the farthest extent of the CoDominium: New Chicago, the New Caledonia system (which contains New Scotland and New Ireland), Maxroy's Purchase, Harlequin, and probably Crucis. For details, see Galactic Map, Map of Known Stars, and Map of objects near the Coal Sack.

Additional notes:

The story "Brenda" implies that Sol, Sparta, and Nuliajuk are near each other but Tanith is distant from these three (WWII 182), but this cannot be correct, as it is established that Tanith is quite close to Sol.

The locations of Makassar and Prince Samual's World are unknown. They are 12 LY distance from one another, and during the 31st Century the trip between them takes about 46 days and involves one jump (KDS 6, 93, 95, 155, 255, 305). Makassar was settled during CoDominium times (GTS 11; Prince 619). Given the pleasant climate of Prince Samual's World and its proximity to Makassar, it might have been settled in the 21st century as well, but if so it probably originally bore a different name, as its name apparently dates from 2273 when it became a Member Principality of the First Empire (KDS timeline).

Finally, it should be noted that an Alderson path can exist entirely within a multiple-star system. According to The Gripping Hand 60, the Sparta system contains two stars: Sparta's orange sun Agamemnon (class K0), and a red dwarf star Menalaus/Menelaus (class M). "The Edge of Darkness" establishes that there is an Alderson tramline between these two stars. The tramlines leading from Menelaus to other stars had not yet been fully mapped in 2091; one of them leads to a red dwarf system 8 light-years away (WWPW 42, 43, 51).

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Map of objects near the Coal Sack

MAP: Trans-Coalsack Sector

This map is a close-up of the Trans-Coalsack Sector and the region nearby. The Locations of the Mote, Murcheson's Eye, New Chicago, Maxroy's Purchase, and the New Caledonia system (which includes New Scotland and New Ireland) were discussed above.

The shape of the Coal Sack in this drawing, as well as the location of the "curdle", are based on the map in The Gripping Hand, (slightly modified to indicate that as seen from the Mote system, the Eye is seen with one edge of the Coal Sack as its background, as indicated on Mote 105, 154.)

As in the previous map, green lines represent single jumps and blue lines are more indirect routes. In particular, the route from New Chicago to New Cal involves several jumps (Mote 32, 36).

Additional stars:

Also, the flare star EST 1310 is located "Galactic South of the Coal Sack", but no specific distance is given. (WWII 177, 197, 213.) It's not on this map, since galactic north and south are towards and away from the viewer from this perspective.

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New Washington and the Size of the Empire

The extent of human settlement in the galaxy grows as time progresses, at least up to the end of the First Empire. The Second Empire seems to be merely retaking old territory; they may not be founding new colonies at all.

In the 2080's, the CoDominium is 200 light-years in diameter, and contains 70 human colonies, according to FL 297. There are variations on these figures: GTS 248 counts "more than 100" human colonies, while PS 2 counts "more than 130" and the Mote prologue claims "200" by the end of the century.

In 3017, the Second Empire includes at least the entire 600 light-years from Earth to the Coal Sack. Mote 458 says that "everyone within two hundred parsecs wanted a seat on the Commission." In 3029, Horvath says the Empire contains "fifteen million cubic parsecs", which makes it about 1000 light-years in diameter. (Mote prologue.)

Horvath also mentions that the Empire contains 200 worlds in the year 3029. In 3046, Jennifer Banda says the Blaine Institute has specimens from 400 Imperial worlds and 30 Outie worlds. Also in 3046, Renner refers "1000 worlds", but this may be an exaggeration. (Mote prologue; Hand 73, 83.)

Despite slight variations, these numbers are roughly consistent. And all the planets mentioned during the 21st century are relatively close to Earth -- with one possible exception: New Washington.

I don't have a good resolution to this problem. I tend to disbelieve the "one jump from New Chicago" version, however. Perhaps the fleet assembled at New Washington before the final series of jumps?

  There is one other piece of data that suggests a CoDominium much larger than 100 light-years in radius. In The Battle of Sauron (second edition) chapter 33, it is stated that Betelgeuse is 180 light-years from Haven. Since Betelgeuse is between 500 and 800 light-years from Earth, this would put Haven at least 300 light-years from Earth, which contradicts the data mentioned above.

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Appendix: Astronomy Books and Web Sites

First, some written references:

And some on-line references:

Also, you can buy the Yale Bright Star Catalogue, 5th Edition (Hoffleit, Warren 1991), but it doesn't seem to be online anymore.

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Star-Map from Jerry Pournelle's Future History
Updated 22 February 2018 by Larry King

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