The SyFy series Battlestar Galactica (2003-10) charts the journey of the titular warship and its accompany fleet of seventy or so civilian vessels from the Twelve Colonies to a refuge on the distant, supposedly mythical planet “Earth”. The revamped series used a scientific advisor – astrophysicist Kevin Grazier – and attempted to use real science to chart Galactica‘s course, although this tended to get less and less prevalent as the show continued. Still, it is quite easy to create a map of the Milky Way Galaxy showing the approximate route of the Fleet and the location of the major planets and landmarks along the way.

Note that this articles contains spoilers for the ending of the Battlestar Galactica TV series. If you haven’t watched it yet (and I recommend it), please avoid the rest of this article.

BSG Map

A map of the local region of the galaxy, with BSG locations estimated. The source map is this one from National Geographic.

When attempting to chart the course of the Fleet, we need to be aware of two things. First of all, the technological limitations of how far and fast the Fleet can travel. Secondly, the major landmarks they passed and how distant they were from one another.

FTL Travel in the Battlestar Galactica Universe

In BSG, interstellar travel is accomplished by means of using an FTL (faster-than-light) drive to instantaneously “jump” from one point in space-time to another. There appears to be no maximum range on how far a ship can jump, but there does appear to be a severe limitation on how far a ship’s computer can calculate a jump safely.

This is because Galactica and the other ships are reliant on their space telescopes to scout a star system before jumping to it. Every star is orbiting the galactic core at a different speed, each planet and moon is circling its parent star at a different rate and of course the speed of light limitation means that you can’t look at a target system and “see” where everything is right “now”. If we looked at Alpha Centauri (4.3 light-years away) and saw a planet there, we wouldn’t be seeing it now but as it was 4.3 years ago. We would have to study the orbit of the planet and then extrapolate it’s current position to work out the jump coordinates to get into orbit. A couple of errors in the calculation and we could end up inside the planet, on the far side of the system or somewhere else altogether.

The further away a star or planet, the fuzzier the images, the hazier the calculations and the more variables that enter the equation. At a certain point the variables become incalculable and the ability to plot a safe jump breaks down: this is known as the “Red Line”. Jumping the red line is possible only if the target area is say a vast area of open space and you can have an error margin of billions of miles or even entire light-years. We see this in the opening mini-series when the Fleet jumps from the orbit of Ragnar (in the Colonial home system) to the Prolmar Sector, a distance of 30 light-years. This is way beyond Galactica‘s red line, but because the target area seems to be pretty big they can get away with it with a reasonable degree of safety.

The maximum precise distance that can be entered on Galactica‘s flight computer is apparently 999,999 stellar units, the BSG equivalent of astronomical units (1 AU=the distance between Earth and the Sun, or 93 million miles/150 million kilometers). This works out at 15.812 light-years. However, this would be an extreme long range jump, taking possibly several days of careful study before a safe jump can be calculated. According to the producers, the Fleet more typically jumps 5 light-years or less at a time, as a jump of this distance can be worked out relatively quickly (the twelve hours mentioned in the Season 2 episode Scattered seems likely).

There are two reasons why the length of time required to work out a jump are fairly long. The first is that most Colonial vessels are designed only for travel within the home system of Cyrannus (or Helios). The Cyrannus system consists of four stars, twenty-four planets, at least 132 moons and four major asteroid belts, all spanning 0.16 light-years. The system is huge (the Solar system is approximately 0.005 light-years wide, extending to the termination shock of the Sun’s influence), but the distances are trivial compared to interstellar travel. Most of the ships in the Fleet only need to travel within the home system and are normally constantly fed astronomical data on the relative positions of every body in the system, which would make cross-system transit fairly trivial. Only the military would have any reason to leave the home system and make interstellar jumps, and even these are relatively short-range. The second reason is that Galactica‘s computers are not networked together (for fear of Cylon computer virus intrusion), so the damage control, mainframe and stellar cartography systems can’t “talk” to one another directly. When these systems are networked together (under extreme duress) in Scattered, they work out jump coordinates in 10 minutes rather than 12 hours.

Cylon FTL technology is comprehensively superior to that of the Colonials. In Lay Down Your Burdens, a Cylon Heavy Raider FTL computer is able to travel from the vicinity of New Caprica all the way back to the Twelve Colonies in just ten jumps. It would have taken Galactica 230 jumps (conservatively) to reach the Twelve Colonies from Kobol, which was significantly closer. This suggests that the Cylons may be able to traverse dozens to a couple of hundred light-years in a single jump.

Lagoon Nebula

The Lagoon Nebula, also known as M8, is a star-forming nebula located approximately 4,100 light-years from Earth, towards the Galactic Core.

Major Landmarks on the Road to Earth

Travelling from the Twelve Colonies to Earth, the Fleet passes through or discovers the following major landmarks:

  • The Twelve Colonies
  • Kobol (reached 50 days after leaving the Colonies)
  • The Lagoon Nebula
  • New Caprica (reached 205 days after leaving Kobol)
  • The Lion’s Head Nebula (reached 50 days after leaving New Caprica)
  • The Star Cluster and Algae Planet (reached 67 days after leaving the Lion’s Head Nebula)
  • The Ionian Nebula (reached 100-120 days after leaving the Algae Planet)
  • Old Earth (aka the Thirteenth Colony) (reached 65-70 days after leaving the Ionian Nebula)
  • The Cylon Colony (reached maybe 100-120 days after leaving Old Earth)
  • New Earth (reached immediately from the Cylon Colony)

Of these landmarks, the only ones that “really” exist are the Lagoon Nebula and New Earth (aka our Earth). The other nebulas appear to be supernova remnants which typically disappear over the course of a few tens of thousands of years as their material is either dispersed by interstellar radiation and solar winds, or absorbed into newly-forming stars and planets, so would likely not be visible now anyway (not to mention being fictional!). The Lagoon Nebula is located 4,100 ly from Earth towards the galactic core, in the constellation of Sagittarius. Rather fortuitously, the position of the Lagoon Nebula allows us to actually map out a lot of the journey by itself.

The Fleet never reaches the Lagoon Nebula itself. Instead, they see it in the Temple of Athena on Kobol in the episode Home, Part II. The Temple holds a starmap showing the precise patterns of twelve constellations as seen from the Thirteenth Colony. These include an image of the Lagoon Nebula in Sagittarius (the episode says Scorpius, but the producers later confirmed this was a mistake). Adama immediately recognises the Lagoon Nebula, except that from Earth it appears larger (he says that the nebula is a “long way” from Kobol). This suggests that the Twelve Colonies, Earth and the Lagoon Nebula form a direct line of sight, otherwise the nebula – not being a symmetrical object – would not be immediately recognisable to Adama.

This instantly gives the Fleet both a direction and rough destination: simply fly towards the Lagoon Nebula until the surrounding stars appear as the constellations do in the Temple of Athena. At that point you’re in the rough neighbourhood of Earth. In fact, from the Temple information alone you should be able to narrow down the location of Earth to a few light-years, or tens of light-years at worst. This seems fine but there is a problem: the information from the trip to Earth is 4,000 years out of date. This is long enough for the stars to move (in their respective orbits around the galactic core) and slightly change the appearance of the constellations. With hundreds of stars to line up in the right location, this may expand the error of margin from a few dozen to maybe a hundred or two hundred light-years: still a reasonable search area but one that would take months to explore thoroughly.

This is likely why later on we see the Galactica crew attempting to actually trace the exact route of the Thirteenth Tribe to Earth. This route seems to be longer, more haphazard and less direct than simply going straight towards the Lagoon Nebula, but it also allows Galactica to pick up additional clues and information, as well as finding important waystops (oases in the desert, if you will) to resupply and regroup. Also, finding the exact places the Thirteenth Tribe visited earlier helps narrow down the search parameters for when the Fleet does arrive in the correct vicinity.

Kobol

A Colonial Raptor orbiting Kobol.

Distances

We are given one direct, very firm piece of information on distance in the course of the series: Kobol is slightly less than two thousand light-years from Old Earth (the Thirteenth Colony). The Thirteenth Tribe left Kobol using slower-than-light, subluminal drives approximately 4,000 years ago. After reaching and colonising Old Earth (the trip took under 2,000 years, but only months from the POV of the people on board the ship because of relativity), there was enough time – decades to a couple of centuries – for several cities to be built on the planetary surface before they were destroyed in a nuclear war which took place 2,000 years ago. The five survivors of the cataclysm then departed Old Earth and reached Kobol during the First Cylon War, approximately forty years before the events of the mini-series. This puts the Thirteenth Colony to somewhere between 1,500 and 2,000 ly from Kobol, assuming the Thirteenth Tribe’s sublight engines were able to reach speeds approaching 99% of lightspeed.

This now begs the question as to how far the Twelve Colonies are from Kobol. According to the map of the Twelve Colonies created for Caprica, Kobol is also c. 2,000 light-years from the Colonies. With the Twelve Colonies, Earth and Lagoon Nebula being in a straight line, this seems to conclusively locate Earth 4,000 light-years from the Colonies with Kobol in the middle. Unfortunately this introduces a number of major continuity issues, most notably that it only takes the Fleet 50 days and 230 (ish) jumps of around 8 light-years each time to reach Kobol (the Fleet actually makes many more jumps due to the events of 33, but once a bit past Kobol they work out it’ll be about 230 jumps to get back home). That means they cover half of the entire distance from the Colonies to Earth in the first season alone. Based on the timescales involved, if the Fleet had simply kept flying towards the Lagoon Nebula from Kobol at the same rate, they would have reached Earth before they even encountered Pegasus!

On this basis we have to assume that the 2,000 ly distance is simply incorrect (it may be what is believed by the Colonials at the time of Caprica but this is in error) and Kobol is much, much closer to the Twelve Colonies. If we go with the 5 light-year distance for jumps given by the writers, that puts Kobol approximately 1,150 light-years from the Twelve Colonies. At 3 light years per jump it would be 690 light-years and so on. This would put Kobol at the one-quarter or one-third distance to Earth, which still seems a bit too close considering the length of time it takes the Colonials to reach Earth afterwards (even removing the sixteen-month layover on New Caprica), but is at least more plausible.

Galactica Fleet

The battlestar Galactica and its accompanying refugee fleet.

The Route of the Caravan of the Heavens

The Fleet departs the Twelve Colonies within hours to a day or so of the initial Cylon attack. It regroups at the gas giant Ragnar at the edge of the system before making a jump way past Galactica‘s red line to the Prolmar Sector, 30 ly distant (the mini-series). The Cylons immediately pursue, appearing every 33 minutes without fail. With Galactica unable to make a normal jump calculation (which Scattered suggests takes 12 hours), it has to instead make a series of rapid-fire microjumps. As long as these jumps are more than 33 light-minutes distant, it means that the Cylons can’t visually “see” the fleet and have to rely on other ways of tracking the fleet (it is hinted that they are being given the jump coordinates by an agent on the Olympic Carrier and are doing the 33 minute thing simply to mess with the Colonials).

After six days and 239 such microjumps, the Galactica crew destroy the Olympic Carrier and effectively prevent the Cylons from directly pursuing them (33). The Cylons instead resort to “staking out” the watering holes – fuel, water and food sources – in the surrounding systems to try to trap the Fleet (Water, You Can’t Go Home Again, The Hand of God). It’s also probable that the Cylon agents in the Fleet at this time are able to signal the Cylons, if at least not providing “live” information on the Fleet’s movements (there is no FTL communications in the BSG universe either) then letting them know where they’ve been.

Fifty days after leaving the Twelve Colonies the Fleet reaches Kobol (Kobol’s Last Gleaming, Part I). From a location past Kobol it is 230 jumps back to the Colonies (Pegasus). Assuming 5 light years per jump, that makes for a distance of 1,150 light-years from the Colonies to that location, putting Kobol at somewhat less, maybe in the 900-1,000 light-year range. At Kobol the Fleet discovers the Tomb of Athena and a starmap showing the constellations of the Twelve Tribes and the Lagoon Nebula (Home, Part II). The Fleet begins heading towards the Lagoon Nebula. Assuming Old Earth and New Earth are in the same stellar neighbourhood (which appears likely from later information) and given that we know that Old Earth is 2,000 light-years from Kobol, that puts the Fleet at roughly one-third of the distance from the Colonies to Earth at this time. This puts the distance from the Fleet to the Lagoon Nebula at this time to around 6,100 light-years.

Starmap

A very rough and approximate map of the major landmarks on the road to Earth.

What happens next is a bit odd: Galactica and the Fleet take a further 205 days to travel from Kobol to New Caprica. This timeline discrepancy was introduced by the writers when they needed to have Athena give birth to Hera between eight and nine months after conception, with conception taking place in late Season 1. Given that the entirety of Season 1 spans about seven weeks and has the Fleet cover one-third the distance to Earth already, this appears problematic. However, there is a possible explanation. After leaving Kobol the Fleet encounters the battlestar Pegasus and destroys the Cylon fleet that has been trailing them since the Colonies, including its resurrection ship (Resurrection Ship, Part II). The destruction of the resurrection ship makes the Cylons a lot warier about attacking the Fleet. This takes the heat off the Colonials and means they can spend a lot longer doing jump calculations, make shorter but safer jumps and also gives them time for much-needed downtime, repairs and maintenance. The Fleet also spends a month undertaking mining operations in an asteroid belt (Scar), whilst Pegasus spends a large amount of time building new Vipers and training new pilots with its simulators.

The Fleet reaches New Caprica (Lay Down Your Burdens, Part I) and settle the planet. A year later the planet is occupied by the Cylons (Lay Down Your Burdens, Part II). Four months later Galactica and Pegasus mount a rescue operation. This is successful, but Pegasus is destroyed in the process (Exodus, Part II). The Fleet then resumes the search for Earth. It is difficult to pinpoint the location of New Caprica except that it is within a dense nebula cloud. This nebula is so thick that, unlike other nebulas in the series, it interferes with DRADIS signals. It is possible that New Caprica is actually located in the outskirts of none other than the Orion Nebula, located 1,350 light-years from Earth. Based on the trajectory and distances given so far, the Orion Nebula is very close to the route from Earth to the Colonies via Kobol. The Orion Nebula also appears in the background of a scene in Scattered, suggesting that it the Fleet is at least in the vicinity. Since the Fleet locates New Caprica by accident, it is even possible that they had already passed the area and doubled back to the settle the planet.

Anyway, after leaving New Caprica the Fleet follows astronomical information from Baltar’s notes and reach the Lion’s Head Nebula fifty days later (Torn), where they find a beacon left behind by the Thirteenth Tribe (which is then destroyed before any information can be extracted from it). At this point, Galactica has taken severe damage from the Battle of New Caprica and is in rough shape. We see exactly how rough in Season 4, when the ship starts showing signs of structural collapse, but certainly it’s already clear that the ship is not operating at full capacity. It can be assumed that the Fleet may be making much shorter and safer jumps at this point.

The Lion’s Head Nebula is home to a rotating pulsar. There are a few pulsars within 1,500 ly of Earth (the closest is about 700 ly away) so this isn’t too much of a problem. From the nebula the fleet finds its way to a dense star cluster (The Passage), beyond which lies the Algae Planet where the Thirteenth Tribe built the Temple of Hopes (The Eye of Jupiter). There are plenty of star clusters at the distance we are looking at, although not quite in the right direction. The closest are the Pleiades at c. 450 light years at a slight tangent from Orion, but the Pleiades are very easily recognisable and if the cluster was supposed to be them, I think it’d have been made clearer. After reaching the Algae Planet, the local star goes nova and provides the Fleet with the next clue, the way to the Ionian Nebula (Rapture). The location of the Algae Planet is unknown, but the destruction of its star would have left behind an interesting supernova remnant. Although completely speculative, I always liked the idea that this remnant would become NGC7293, aka the Helix Nebula, simply because it bears an uncanny resemblance to the Eye of Jupiter.

Helix Nebula

The Helix Nebula, NGC7293, is a supernova remnant located approximately 714 light-years from Earth.

This then causes a major problem: the Ionian Nebula is said by Lt. Gaeta to be thirteen thousand light-years from the Algae Planet (or 2,600 jumps at five light years a time!). Reluctantly, I have to conclude that this distance – which grossly at odds with all other distances given in the series – is erroneous and Gaeta actually meant thirteen hundred ly. This is still problematic but not as much as trying to fit in a 13,000 ly side-trip into the series, especially given they make the trip in 120 days max (from Rapture to Crossroads, Part II) which is simply impossible given the limitations of Colonial technology. 1,300 ly is about the distance from the Orion Nebula to Earth, so it’s possible that this side-trip is actually in error and takes Galactica and the Fleet way off course. It’s notable that the Thirteenth Tribe merely saw the Ionian Nebula supernova in the sky, they didn’t necessarily travel there directly which the Fleet did. This is backed up by the fact that in the first few episodes of Season 4 the Fleet seem stumped by what to do next and have to rely on the conveniently-returned Starbuck to guide them to Earth, which after seventy-odd days of flying in circles she eventually does (Revelations).

Old Earth is a nuclear wasteland, completely uninhabitable. The Fleet begins a thorough, exacting search of the surrounding star systems for a habitable planet to settle on (Sometimes a Great Notion). At this point the constellations from Old Earth match those from the Temple of Athena – which makes sense – but of course we know that those constellations also mostly match those as seen from our Earth. As a result, this puts Old Earth and New Earth in the same stellar neighbourhood, meaning that the Fleet may have found it anyway if the search had continued for much longer.

Instead, of course, Galactica is forced to mount an assault on the Cylon Colony, the Cylon mobile command centre which has been moved into close proximity of the Fleet to oversee its final destruction and the kidnapping of Hera. The Colony is located in close orbit above a black hole. Galactica launches the rescue mission and it is successful. However, with the Colony’s orbit compromised and decaying, Galactica has to make an emergency jump. Using the coordinates provided by studying the mysterious “music”, Starbuck programmes Galactica‘s FTL computer to jump 362,321 astronomical units, or 5.77 light-years. The ship then arrives in orbit above New Earth (Daybreak, Part III).

There isn’t a black hole system 5.77 light-years from Earth, but as the closing moments of the finale reveal this isn’t necessarily a problem: the series is revealed as having taken place 150,000 years in the past. 150,000 years ago it is possible that a black hole system passed within 6 ly of the Solar system and the galaxy’s rotation has carried it a significant distance away from us in that time.

So there you have it. A lot of speculation, because the writers of the show weren’t always paying attention to things like time, space and distances, but broadly speaking we can see BSG as a surprisingly constrained show, spanning just a few thousand light-years rather than implausibly trying to take in the entire galaxy like some shows do. Something that does come through in all of this is how utterly vast space is and how even a tiny proportion of the galaxy (Galactica traverses approximately 3% of the width of the galaxy in its journey) is unfathomably huge.

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