D&D 5E What is the Astral Sea according to 5e?


Mind Mage
What is the Astral Sea according to 5e?

I have some sense of how the cosmology will work for D&D 5e and its Spelljammer setting option. There is a video interviewing Perkins who explains the basics of how this cosmology will work.

What is: Wildspace and the Astral Sea?

There still is some room for personal interpretation and speculation − heh, and I will do so in this post and thread. What is clear is:

Astral Plane = Wildspace + Astral Sea

Essentially, "wildspace" is an area around a star (namely a sun) or some kind of stellar system, such as a nebula. Then the "astral sea" is the misty dreamy scape between these stars. Indeed, "astral" literally means "starry", and the stars are visibly prominent from within the astral plane.

My current impression is, within the aster, the distant stars look something like lamps within a fog. Here is where my speculation begins.

Note, I use the term "ether" to mean the stuff that the ethereal plane is made out of. Ether is the "quintessence", the fifth element, that all of the other elements are made out of. Ether is the same thing as "force", like the force of gravity or the force of telekinesis. Force is remarkable because it is both physical and immaterial. It is also possible to make constructs out of ether, like force shields, or the virtual bodies of ghosts. The "shallow ether" is the part of the force that exists in the material plate, including gravity and the atomic forces that keep atomic substances together. The "deep ether" is a spirit world that lacks a connection to the material plane.

By analogy, I use the term "aster" to mean the stuff that the astral plane is made out of. Aster is pure "thoughtstuff". It lacks force and matter. It follows its own cognitive rules, and has its own experiential properties. The astral plane is a mindscape, where dreams, symbols, and cultural archetypes take on a life of their own, whose closeness or distance is as near or far as ones ability to contemplate them or have affinity with them.

It is significant, the wildspace is part of the astral plane − not the material plane.

In reallife, outer space is mostly an empty, bleak, and lonely void. This part the material world is "space" − roominess − with little or no matter in between. Even forces are faint from far away substances.

As far as I can tell, the same is true in the D&D multiverse setting. When a character is in the material plane, on the planet of Toril, they look up thru the dark emptiness of outer space and can notice the extreme isolation of it.

However. When this same character dematerializes, and forms a virtual body made out of thoughtstuff, one can roam the astral plane to explore a different kind reality. Within the mindscape of the astral plane, the space between planets and stars is an ocean teaming with life. This life is the dreams of planets, animals, and peoples. And is wondrous.

The wildspace is the part of the astral plane that is within the influence of some point of light, a sun or comparable stellar system. The distance of this influence seems to correlate with a stars pull of gravity. The star itself and the objects around it defacto have minds that exert a mindful presence, a kind of animism. They exist at the level of thought as well as at the levels of force and matter. Within the wildspace, the star and its vicinity is a vivid experience of spectral colors and the dreams of nearby mindful beings.

But the emptiness between stars is different. Here the astral vividness diminishes, and the thoughtstuff of the vacuum is a mistiness. Something like a silvery fog with subtle hints of whitish reds and purples. The distant stars shine thru this mist.

In the material plane, the stars are impossibly far away. Unreachable. But it is possible to hyperjump out of the material plane, to travel across the mindscapes. To travel at the speed of thought.

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Mind Mage
Here is the description of the astral plane in the 5e Players Handbook.

The astral plane is the realm of thought and dream. Visitors traveI as disembodied souls to reach the planes of the divine and demonic. It is a great, silvery sea, the same above and below, with swirling wisps of white and gray streaking among motes of light resembling distant stars. ... Occasional bits of solid matter can be found here, but most of the astral plane is an endless open domain.


According to 5e, the astral plane is a level of existence of thoughts and dreams, and immaterial virtual bodies made out of thoughtstuff.

Note, there is awkward wording about "matter". I take this to mean, there are virtual thought constructs that behave as if solid matter, in contrast to most of the astral "sea" that is "swirling wisps".

The 5e Spelljammer setting coheres with the 5e Players Handbook setting. Perhaps the only difference is, where the astral sea in the Players Handbook has "light resembling distant stars", in the Spelljammer setting we learn that these lights actually are the distant stars.

I find it intriguing that the 5e spelljammer ships of the astral sea, have actually dematerialized out of the material plane, and exist as thought-constructs sailing thru a mindscape sea. They are flying in a dream.


Mind Mage
Planescape Cosmology.png

I find it intriguing that the 5e spelljammer ships of the astral sea, have actually dematerialized out of the material plane, and exist as thought-constructs sailing thru a mindscape sea. They are flying in a dream.
I think matter that enters the Astral Sea is still matter. A person is only made of thoughts if they Astral Project themselves. The Githyanki are still flesh and blood creatures.


Mind Mage
I think matter that enters the Astral Sea is still matter. A person is only made of thoughts if they Astral Project themselves. The Githyanki are still flesh and blood creatures.
I understand the astral plane to be strictly immaterial.

It is impossible for matter to exist in the astral plane, in the same way that it is impossible for matter to exist in a dream. To dream about matter is a purely symbolic thought construct.

Divine thought created the material world. Then the astral constructs are a kind of architectural blueprint for the material world. The aster is a world of information.

Angels are thought constructs − information patterns, sometimes called intellects − by definition without flesh and blood.

An astral body is a virtual body, an information construct. One can use this information to translate and inform a material form, thus materializing a body of matter in the material plane.

In the same way that angels within the aster are immaterial, githyanki within the aster are psionic thoughts and memories that are immaterial.

When astral angels physicalize into the material plane they normally do so via conjuration to form a temporary physical avatar, namely a virtual body made out of physical force. However it is also possible for an angel to materialize into the material plane as a body of flesh and blood. Angels rarely become flesh and blood because of the limitations of matter and the resulting loss of angelic information.

Such hyperjump space travel is actually dematerializing here and rematerializing there. It is a method of teleportation, but the extreme distances prolong consciousness during the process.
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Mind Mage
I visualize the astral, ethereal, and material as overlapping concentric circles.

These planar names, refer to thought, force, and matter, respectively.

Vere Cosmology - Astral Ethereal Material - Simple.png

Everything that exists is made out of positivity. Pure negativity is nothingness, nonexistence. Negativity allows positivity form different kinds of things within its emptiness. Without negativity, positivity is undifferentiated infinite positivity. Negativity is an important aspect of creation. For example, at a material level of existence, positivity is the energy of atoms (somethingness), and negativity is empty space (nothingness). Space allows atomic energy to form virtually unlimited forms of different kinds. At a level of force, positivity is a push toward creativity, such as a big bang, and negativity is a pull toward annihilation, such as a black hole. The level of thought refers to consciousness, where positivity is soul and negativity is amnesia is nonconsciousness. Positive thought includes creativity, hope, and wellbeing. Negative thought includes destruction, despair, and illness.

Withn the interplay between positivity and negativity, plane of thought exists. The thoughtstuff that thought constructs are made out of, is also called aster. During the creation of the material plane, these astral thoughts planned out the influences of force and the substances of matter, like a blueprint for a building. Within this creation is the primordial force of the big bang, pure radiant energy, sometimes called the point of light within the darkness. Eventually this explosion of positivity evolves into the electromagnetic forces, gravitational forces, and the atomic forces of all that exists within the material world.

These are overlapping concentric circles. The level of matter includes: matter, force, and thought. For example, a human body of matter includes some degree of gravitational force, as well as a conscious mind of thought. The human might not be able to perceive the rest of the astral plane, but each human mind is part of the astral plane, even if only subjectively experienced from the perspective of the material plane.

Similar to the way a human body includes a human mind, the various phenomena of nature have animistic minds. A river has a mind, a mountain has a mind. In this way, features of nature exist within the astral plane, and are especially part of its wildspace that teams with life.

In some ways, force is a bridge between matter and thought. Force includes reallife physical force like gravity − but it also includes fantasy physical force like telekinesis. The material body of a human has an aura force that permeates it and extends out from it, similar to a light shining from a lantern, intense around the body but perceptible from a distance away. This bodily force is often called "ki". It is possible for a mind to manipulate this aura of force to alter ones body or to influence and manipulate an object or mind, a distance away.

Similar to the way a body has an aura of force that emanates from it, the entire material plane has an aura of force that emanates from it. Sometimes this is understood as an echo from matter. This emanation from matter is called the ethereal plane. More specifically, the parts of the ethereal plane that are beyond the material plane are called the "deep ether". The deep ether is spirit worlds that have force (and minds), but lack a correlation to a material location. The deep ether tends toward freeform. Deep ether can be responsive to the desire of a strong mind. The shallow ether is the physical forces that are actually part of the material plane, including gravity. But these shallow ethereal forces also include the forces of manifesting fey, poltergeisting ghosts, ethereal creatures, and so on. The shallow ether can see the material plane, and if ones force is strong enough even physically interact with the material plane telekinetically, or via a virtual body avatar conjured out of force. Most ethereal forces are subtle and negligible within the material plane. Generally only a strong mind can focus and shape a significant amount of force to alter the material plane.

Each of these three planes, astral thought, ethereal force, and material matter, can resonate strongly with either positivity or negativity.

• Astral positivity: celestial dominions
• Ethereal positivity: feywild
• Ethereal negativity: shadowfell
• Astral negativity: fiendish dominions

The astral plane of thoughts, include ethical alignments. Here, altruistic impulses are celestial Good, while predatory impulses are fiendish Evil. Between the positivity and the negativity are shades of gray. Actually, there is no gray, but rather shifting moments of positive and negative, and various frequencies. In the interplay between, there can be Evil celestial creatures or Good fiendish creatures, albeit rare. The feywild tends toward Good and Neutral, but Evil exists there too. Likewise the shadowfell tends toward Evil and Neutral, but Good exists there too.

Strictly speaking the positive and negative of the material plane is matter and space, respectively. However, there are places within the material plane that exhibit strong affinity with celestial and fey positivity, or else with fiendish and shadow negativity. To the extent that these material places cohere, they can be palpably Good or Evil, or even alter in dreamlike ways where the threshold from matter into ether or aster is thin.

Vere Cosmology - Astral Ethereal Material.png
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Mind Mage
Question: if the astral is just a thoughtscape, why can’t PCs do anything they can think of?
The astral plane is a thought scape, where symbols, archetypes, cultures, ideals, take on a life of their own. One must learn how to navigate. For example to arrive at a dominion of Good ethical ideals normally requires oneself to be Good, whence the symbolic affinity with that dominion.

Part of the magic of a spelljammer ship is to dematerialize into a thought construct, but also is to navigate the thought scape, including by linguistic means.

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