The following quote is taken from a discussion on the internet (it was one of the Google newsgroup archives) and gives a nice account of the way the successive spiritual regions and the spiritual ascent are described in the Radha Soami teachings. Here only the four major regions are described, however other Sant Mat teachings differ in number and detail of the spiritual worlds. While the term Astrol is well established in Sant Mat, the terminology Causal, and Supracausal here replaces older and more traditional (but also unfamilar to the Western reader) names like Trikuti, Daswan Dwar, Sunna, and Banwar Gupha.
Where the Journey Takes Us
As we are absorbed in the inner Light, we pass through the inner sky, stars, moon, and sun, and come to the gateway of the astral realm. We reach Sahansdal Kanwal, the capital of the astral world. This is a magnificent region, described as a thousand-petalled lotus, from which Light and Sound stream forth. The astral region has a brighter Light than this physical region and is permeated with the beautiful Music of the Sound Current that manifests own distinct Sound.
The soul next travels from the astral region to the causal region. The causal region has its own distinguishing Light and Sound. In this region the soul functions with a causal mind and is one with the Universal Mind. The causal region is more ethereal and its Light is brighter than that of the astral region.
Next, the soul travels to the supracausal plane. Here we find a pool of nectar, called the Mansarovar in which the soul bathes and sheds its causal body. The soul is now covered only with its supra-causal layer. This region is beyond the mind and senses. There is absolutely no physical language that can even give us an inkling of what the supracausal realm is like. We have only pale analogies. Since the physical, astral, and causal minds have been left behind in the lower worlds, mind is of no use to us here. It is an experience of the soul. The soul experiences greater bliss and joy than in the three lower regions. The supracausal plane also has its own distinguishing Light and Sound that help the soul recognize where it is. It is in this plane that the soul, losing the forgetfulness that daunted it in the lower planes, cries out "I am That." It realizes, "I am the same essence as God."
Continuing further, the soul finally enters the purely spiritual region of Sach Khand or Sat Lok (True Region). The soul is magnetically pulled to reunite with God. The joy and ecstasy now reach an intensity beyond any human thought. Here, the region of pure Light and Sound bathes the soul. The soul is finally fulfilled.
It is with exhilaration and joyousness that the soul in Sach Khand experiences its own true state. It is in a state in which there is no pain, no sorrow, and no death. All is joyousness, love, and perpetual happiness.
Shabd Meditation has also been called Surat Shabd Yoga. Surat Shabd Yoga literally translates as follows: Surat means the soul. Shabd means the Sound Current, and Yoga means yoking or union. By uniting the soul with the Sound Current one can take the spiritual journey to the higher regions until we ultimately merge back in God.