A Brief History of Black Holes in Infinite Space: From Navigational Hazards to Interstellar Shortcuts
Every game in the Infinite Space trilogy has featured black holes on every randomly generated map. However, their depiction varies slightly between individual games, although they are generally considered to be navigational hazards throughout the whole series. With that in mind, let's take a look at these vast cosmic whirlpools and how they came to be regarded as potential gateways to interstellar shortcuts in later games.
In the original Strange Adventures in Infinite Space, black holes had to be avoided at all costs, since their immense gravitational pull would ensnare and destroy any flotilla that got too close to them (with the exact distance depending on how fast that flotilla could travel between star systems); if that flotilla was your own, the game would immediately end. Black holes were spawned randomly at the start of a game, and would remain hidden unless you discovered them by getting close enough. Unlike in later games, however, you could rename any black holes you found, and there were hardly ever more than two of them on any map.
Discovering a black hole in the original game. Note that you can rename any black holes you find in Strange Adventures, a feature omitted from both sequels.
Black holes were left mostly unchanged for Weird Worlds and Sea of Stars, with a few exceptions. Having an Anti-Graviton Shunt (a new item introduced in Weird Worlds) installed on any ship in your flotilla would render it immune to the effects of a black hole, and you can even visit them, although you won't find any items there. While orbiting a black hole, you can even enter it and emerge in another black hole (including the one you just entered), regardless of whether or not you have already discovered it. Doing so, however, would run the risk of damaging a random piece of equipment in your fleet, but only in Weird Worlds.
In addition to this, if the map contained the hidden space station Primordius, it would always spawn at a black hole. In Sea of Stars, it was also immune to detection via a Continuum Renderer Array; as for the black holes themselves, there were now always five of them on any map (whereas in Weird Worlds, smaller maps would have fewer black holes), and each one would be marked in red on the map after it was found, unless you were using an Anti-Graviton Shunt.
Interestingly, Weird Worlds also allowed you to completely remove NPC fleets (except for the Klakar Frigate) from the map without actually attacking and destroying them in direct combat. This trick requires the use of an Aethric Mirror and an Anti-Graviton Shunt. To pull it off, you'll need to visit a black hole, and use the mirror on an NPC fleet (except for abandoned vessels and Primordius, all of which are immune). If successful, you will swap places with the NPC fleet and destroy it in the process.
From my own observations, this is an overpowered tactic. In fact, one theory as to why the Aethric Mirror was removed from Sea of Stars is that the developers deliberately wanted to prevent players from completing the game in such anticlimactic fashion. Then again, considering how much easier it is in that game to destroy hostile fleets by conventional means, it may not even have been necessary to consider including the Aethric Mirror on the list of obtainable items this time around.
Above, from top: Three types of black holes in Sea of Stars: hazardous (red), explored (green) and non-hazardous (purple).
Given that traveling through black holes no longer damages any of your ships (or any equipment installed on them, for that matter), it is now more viable than ever to use them as shortcuts through interstellar space if you have an Anti-Graviton Shunt. If you want (or have) to visit a distant star system on the map that would take a very long time (around 365 days, or 1 Earth year) to reach via conventional means, it may be faster to find a nearby black hole, then enter it, and from there, keep entering other black holes until you find the one closest to your desired destination. From there, it should be a short hop to your final destination - saving you plenty of time compared to a direct approach.
In short, black holes seem intimidating for newcomers to the Infinite Space trilogy, but you'll quickly learn how to avoid them - unless you have an Anti-Graviton Shunt, in which case you would be better off exploiting them instead for a faster trip through Sector Prime.