The black hole provides a rich symbol of the inner journey of consciousness. It is the last stage in the evolution of some stars. All stars, including our own sun, give off heat and light during their lives by converting hydrogen into helium in the nuclear fusion furnace in their interiors, This energy released in the centre of the star not only warms its planets and sustains life on them, but also enables the star to maintain the same size for billions of years. The star in this stage of nuclear burning is a balance of two colossal forces. There is the inward force of gravity which makes the star want to collapse in upon itself. But exactly counterbalancing it is an outwardly directed force due to the flow of heat and light from the centre, which exerts an outward pressure on the layers of the star and prevents the star from collapsing to a smaller and smaller size.
A time comes, however, when the star has exhausted its internal nuclear fuel. Then it begins to contract and become more and more dense. If the mass of the star is great enough, roughly more than three times the mass of our own sun, then there is no force which can stop it from collapsing under its own weight down to a point of infinite density. Space and time are severely distorted in the region of such an object, called a black hole, because its gravitational field is so strong that nothing, not even light, can escape from the black hole once it gets closer than a certain distance called the event horizon (about 15 km. for a black hole of three times the mass of the sun).*1
General relativity predicts some interesting physical phenomena around and within black holes. First of all, clocks or timepieces run at different rates depending upon the gravitational field they are in. The more intense the gravitational field - and black holes have the most intense gravitational fields, the slower the clocks run. Also even biological processes slow down in a gravitational field; so that if there is an observer with a clock deep in a gravitational field, his thought processes also slow down and he perceives his clock running at the normal rate. An observer far away from a black hole, however, sees clocks running slower and slower, the closer they get to it.
So if, from outside, I watch an astronaut fall into a black hole, I see him fall more and more slowly until at the event horizon he seems to come to a complete stop; and as I see it, his clock has slowed to a stop, that is, time has come to a stand still. The in-falling astronaut, on the other hand, does not notice the slowing of time; his clock seems to tick along at its usual rate. If he were to look back out at the outside universe, he would perceive clocks there running at enormous rates. When he reaches the event horizon, outside clocks seem to be running infinitely fast.
In a moment the astronaut sees the whole history of the universe pass. Thus an infinite amount of time as measured far away from the black hole passes before the astronaut reaches the event horizon. He never makes it as seen from outside. From the astronaut's point of view, only a short time passes and he quickly passes on through the event horizon.
The astronaut falling into a black hole is analogous to a meditator moving inward in his meditation. Patanjali's Yoga Sutras imply that as a yogi progresses inward in meditation, his subjective time relative to the outside world slows down. According to Vyasa in his commentaries, a moment is defined as the period in which a yogi can notice the most minute mutation or change in that on which he fixes his attention. In this philosophy the mutation of something is just the sequence in which its characteristics are manifested to consciousness. Time is then just the intellectual concept regarding sequences of changes or manifestations of characteristics.
When the yogi, looking within at his object of meditation, keeps his concentration one-pointed for a long time, as measured on external clocks, it would be one moment for him, yet many moments for another mind in a more quickly mutating state of consciousness. The deeper the yogi goes in meditation, the more absorbed and fixed his mind becomes and the slower time flows, as measured by succession of moments. According to K. L. Seshagiri Rao, the moment in dharana is 12 seconds, in dhyana 12x12 equals 2 minutes 24 seconds, in samadhi 12x12x12 seconds equals 28 minutes 48 seconds, and in nirvitarka samadhi 12x12x12x12 equals 5 hours 45 minutes and 36 seconds. As the yogi reaches the state of discriminative knowledge, time stops altogether, just as at the event horizon of the black hole.
Samyama is dharana, dhyana and samadhi practised together. Discriminative knowledge comes to the yogi when he practises samyama on the moment and its sequence. When samyama is practised, 'the light of knowledge (prajna) dawneth.' The past, present and future are all known together at the same moment to the yogi who has discriminative knowledge. This knowledge is intuitional, comprehensive of all things, and has no sequence.
Such a yogi is omniscient. He has transcended time and space, but after becoming disinterested even in omniscience, he experiences an expansion of consciousness and 'then on account of the infinitude of knowledge... the knowables appear as few.' He is enlightened, liberated, has attained moksha. His mind's natural activities have ceased as there are no more samskaras (latent impressions); but the yogi can come back, so to speak, by creating a mind from pure ego for the purpose of giving instruction on spiritual knowledge for the benefit of all creatures.
The created mind is free from fluctuations and samskaras and can be terminated at will. The moksha or freedom attained by such a yogi is not merely the freedom from rebirth. This yogi has become a 'co-creator'. The co-creator participates in the creation of the future. Of all the possible futures, the co-creator makes manifest whichever future he desires.
*1. W. J. Kauffman III, The Cosmic Frontiers of General Relativity, Little, Brown and Co., Boston, 1977.