The astral planes are usually conceived as either realms that overlap the physical in different layers, or as states of consciousness that need to be traversed in order. Usually, the progression is from the physical to the etheric, then the astral, then various other realms or spirit worlds beyond the astral.
In astral projection the traveller finds him- or herself in an apparently real domain, which has no parallel to any physical setting. This is termed by New Agers and occultists among others as the astral plane or "the astral". Environments here may range from populated to unpopulated, artificial to natural to completely abstract environments and from beautific to horrific. Here, normal physical laws often do not apply. The quality of detail ranges from crude to vivid and fascinating. Projectors may gain access to visions of the past or future of Earth, and to the Akashic records. It has been said that space and time do not exist on the astral plane in the same way they do on earth, or that they can be transcended. Many travelers have theorized that people having dreams travel to the astral realms. Travelers have reported seeing dreamers enact dream scenarios on the astral plane, unaware of the more extensive and varied non-physical environment surrounding them. Some also claim common movements in dreams, such as falling or feeling like you are walking through quicksand, is the astral body in action.
The astral environment is often divided into levels or planes. There are many different views concerning the overall structure of the astral planes, and many different numbering schemes applied to them. These planes may include heavens and hells, places where people go immediately after death, transcendent environments for those who are "more enlightened," and other less-easily characterized states.
Though closely related to astral projection, in etheric projection a projector encounters mainly that which exists physically, moving about in a (usually invisible) etheric body. The term was used as far back as the 1940s, by Dion Fortune in her book Psychic Self Defence. In contrast to astral projection, during this type of experience, there are no fantastical worlds, or self-absorbed encounters; the majority of the experience can -hypothetically- be validated.
The world encountered during etheric projection may seem to be at variance with physical reality if strict mind control is not maintained. Robert Monroe describes this type of projection as a projection to "Locale I" or the "Here-Now", and describes it as containing people and places that actually exist in the material world. Robert Bruce refers to a similar area as the "Real Time Zone" (RTZ) and describes it as the nonphysical dimension level closest to the physical.
In Western theosophy, each subtle body is functionally distinct. Since the etheric body and astral body are not the same, they cannot represent the same kind of psychic activity.
According to Max Heindel, the etheric "double" serves as a medium between the astral and physical realms. Ether, also called prana, is the "vital force" that empowers the Physical forms in order for change to take place. This means that when one views the physical during an OBE, they are not technically "in" the astral realm at all.