Archives of Candlekeep: A Dip in the Astral Sea

Archives of Candlekeep: A Dip in the Astral Sea

This article was first broadcast in Episode Two Hundred and Twelfth on 25th May 2022.

Note: This article was adapted from an episode script, and so there may be parts that don’t flow well when read, because they were initially designed for broadcast.


Recent revelations about Spelljammer have said that the phlogiston is no more. Where the highly volatile mystery substance used to fill the space between local star systems, apparently that void is now going to be filled by the Astral Sea, or at least something called the Astral Sea.

A lot of Planescape fans probably raised their eyebrows and worried a bit when they heard that. Because until we get some more details, it’s possible the 5th edition Astral Sea is going to be very different from before.

Like most things about the D&D cosmology, the astral sea was something that sort of “appeared” over time. Several resources and adventures during original D&D had the concept of multiple planes of existence. Also astral projection was something baked in from the beginning. One of the original spells in D&D was called “Astral Spell” and it talked about sending a character’s astral body to the so-called “astral plane”.

Eventually players and writers started toying with the idea that astral projection like that had risks beyond the ones outlined in the spell. As far as the spell was concerned, if someone tried to use magic while astrally projecting there was a risk the astral body could discorporate and end up in one of the hells or something similar. But the spell referenced “others on the astral plane” and people started to run with that idea.

In a pattern familiar to those who examine the historiography of Dungeons and Dragons, these disparate interpretations persisted independently until the intervention of the Tactical Studies Rules company. The company did not initially put a major focus on the cosmology and non-material areas of the game; by the 1980s when first edition was largely being developed, the moral and religious paranoia surrounding the game was paramount. The company’s response was to downplay obviously religious or perceivably satanic aspects of the game and focus on more traditional fantasy realms and creatures.

It was not until later in the decade when initial panic was subsiding that the company judged fan interest in more cosmological and ethereal topics outweighed the potential risk of backlash. Primarily under the direction of one Jeff Grubb, also notable as being a primary designer of the hell-spawned abomination of fantasy space traversal that should burn in a pit of torment, TSR released the first Manual of the Planes in 1987.

Anyway, the original manual of the planes was the definitive source of information on anywhere a character might end up that wasn’t a physical plane. That included all the elemental planes, the positive and negative energy planes, the ethereal plane, and all the various heavens, hells, and non-judgmental afterlife locations a creature could end up in. A lot of the treatments were mere shadows of what some of those planes would eventually turn into (the Nine Hells only had a four page entry, for example) but it was the first time all a lot of the info had been put together and made official in any way.

One of the larger entries was on the Astral Plane. It hadn’t acquired the “sea” bit yet, and it wouldn’t for a while, but other than the name all the basics were there.

The volume and the things it covered proved so popular that it’s one of the few resources that was reprinted for every edition of D&D up through fourth. That’s  saying something given how much fourth edition messed with the cosmology of the multiverse. Despite that, a lot of the information and properties of the Astral sea have been the same each time.

The Astral plane was basically the connective tissue between all the planes of existence. If a plane wasn’t literally in contact with another one (such as how the Feywild and Shadowfell supposedly exist sort of “wrapped around” the material plane) all the space between was the Astral Sea.

The Astral Sea is described primarily as a realm of thought and intention. If that sounds familiar it’s because the plane of Limbo in D&D operates in a similar fashion, but the Astral sea is so vast that it’s harder for beings to permanently affect it. Unless someone runs into a physical object or creature that’s floating around in the sea, it mostly looks like a continuous, glowing, thin cloud.

It has no gravity in most incarnations, though if someone believes strongly enough that there is gravity and decides which way is down, they will start to fall. That proves true of all directions, though; any creature capable of thought in any way can choose a direction and they will simply start floating that way.

Entry to the Astral plane is possible through two different methods. The first is the aforementioned astral projection. This is the more common method for many creatures that begin in the material plane. The individual’s astral body leaves the physical incarnation but remains tethered by a so-called “silver cord.” The physical body goes into stasis where it neither ages nor requires sustenance, while the astral body exists in the Astral Sea. The astral body enjoys the benefits of a non-corporeal existence, however there is significant peril if the silver cord is severed. In almost all cases, the severing of the cord results in the loss of control of the astral body to whatever stronger willed creatures persist in the area and the death of the physical body. The most well-known cause of such risk is the silver swords of the githyanki species.

It is also possible to enter the astral plane physically in the same manner any other planar traversal would occur; planar shifting, persistent portal, or a door in the city of Sigil. The Astral Sea had links to all known planes of existence at all times. Said links typically manifested as so-called “color pools” where the hue of the manifestation gave insight into the connected plane. However, the manifestation of those portals was inconsistent and geographically dispersed. In most volumes it was stated a travel time of eight to twelve hours would be required for any group or individual actively searching for a pool, and locating a pool connecting to a desirable plane was by no means guaranteed.

Fortunately, in one sense whoever was searching could take their time. With, say, the Feywild, you can go in for an hour and it’s 50/50 whether a few minutes or a hundred years had passed in the material world. With the Astral Sea, time is always massively slowed down from the perspective of the other planes. The conversion rate is usually given as 1000 years in the Astral Sea equates to one day in the material plane. And that applies to individual bodies as well. People in the Astral Sea will notice the passage of time as normal, but if they’re a creature that ages, they will do so at the rate of wherever they came from. So again, if you spend 1000 years in the Astral Sea, your body will only age a day.

On the other hand, as hinted at earlier, you probably won’t want to take your time in the Astral Sea because there are other things there and they aren’t all friendly.

The githyanki are some of the most well known travelers in the Astral Sea, mostly thanks to Planescape. Planescape as a setting and series of games introduced the idea of literally sailing through the astral plane, and is primarily responsible for the name “Astral Sea.” Boats (again, based on water sailing ships) that could travel through the Astral Sea became a fixture of the setting once Planescape took off, and some of the most common sailors were the silver-sword wielding marauders. That was, of course, when they couldn’t find a dragon to ride instead.

However, those who know their D&D lore know the Githyanki didn’t come from the Astral Sea, they just like to travel there a lot. Common theory says that’s true of most things in the Astral Sea; it’s believed very few, if any, creatures are actually native to the plane. There are several creatures that were given labels as “astral-” whatevers, including specter-like Astral searchers, large astral whales, and even astral dragons, but most people who’ve studied them believe the creatures actually started somewhere else and simply adapted to living in the Astral Sea.

The only possible exception is the beholder-faced, crab armed, gargantuan monstrosity known as the Astral Dreadnought. It’s believed to be a true native of the Astral Sea only because nobody can figure out where else it possibly could have existed, apart from someone’s nightmares.

Apart from the proliferation of living beings either quazi-native to or traversing the plane at any given time, there are other objects that have become trapped there. The volatility of portals and the various activities and machinations of powerful beings has occasionally caused landmasses to be cast adrift in the nothingness. Some of the landmasses resemble floating islands, featuring a landscape on one side and tapering cliffs on all others. Others simply manifest as great hunks of dirt, rock, or more esoteric matter, with no cultivated or designed surface.

Some of the aforementioned formless hunks of matter are in fact corpses. It is possible for beings claiming to be deities to meet their end, and in many cases when that occurs, the resulting lifeless husk ends up in the Astral Sea. There are various causes for this; in some cases the body is intentionally set adrift as a matter of sanitation in the original plane. In other cases the deity was engaged in a conscious or habitual activity that ensured their body remained in their original plane and absent a conscious effort the default state was ejection to the Astral Sea. Regardless of the reason, the size and often unique form of these bodies is such that many smaller and mortal beings are unable to discern their true nature absent extended exposure.

The Astral Sea was originally designed as an obstacle; it’s not supposed to be the best way to do anything in particular as far as planar travel. However, the design of the cosmology in D&D makes it so the Astral Sea may end up being a group of characters’ only option. The Astral Sea was the easiest plane to get into in 3.5 and earlier, and even by 4th edition it was still easier to end up there than anywhere other than the Shadowfell or the Feywild. It’s also easiest to move in; as we mentioned, all you need is a functioning brain. Also as mentioned, that ease of use comes with tradeoffs; whether you’re astrally projecting or physically going there, it’s going to take a lot of your character’s time to get anywhere because things are so spaced out. Also, the longer you remain there, the more likely it is that something will find you and try to make your life miserable.

Now as far as 5th edition goes, as of when this was recorded we don’t know exactly how the Astral Sea has translated to its new place as the bridge between Spelljammer star systems. It would seem like all of the “freely moving by thought”, time slowdown, and portals to alternate planes stuff would need to go to fit with Spelljammer. Then again, suddenly having access to air again after a certain amount of traveling through space and shrinking the “real world” time scale would solve a lot of problems with interstellar travel that would otherwise be there. Also, several entries about creatures from Spelljammer have already mentioned the dead gods thing. So it’s very possible the new Astral Sea will look and feel a lot like the old one. We’ll just have to wait and see.