Yogic Science

     Yoga or The Yogic Science is a part of  Indian Culture. It is  a Pure and fundamental Science of Human body , it explains about body, mind and soul. There are plenty of yoga techniques such as Kundalini yoga Raja yoga, Kriya Yoga, Hamsa Yoga, Hata yoga etc. Sri patanjali maharshi gave us more then 109 yoga sutras  that constitute the foundational text of Ashtanga Yoga also calle Raja Yoga is a form of meditation in which the mind is trained to be focused at one point. It aims at the calming of the mind using a succession of steps, culminating in samadhi. According to the samkhya-based Raja yoga-philosohy, this results in kaivalya, the recognition of the pure mind, and the subsequent liberation from rebirth.
    
     Raja yoga is traditionally referred to as aṣṭanga (eight-limbed) yoga because there are eight aspects to the path to which one must attend. The eight limbs of ashtanga yoga are:
Yama – code of conduct, self-restraint
Niyama – religious observances, commitments to practice, such as study and devotion
Āsana – integration of mind and body through physical activity
Praṇayama – regulation of breath leading to integration of mind and body
Pratyahara – abstraction of the senses, withdrawal of the senses of perception from their objects
Dharaṇa – concentration, one-pointedness of mind
Dhyana – meditation (quiet activity that leads to samadhi)
Samadhi – the quiet state of blissful awareness, super conscious(?) state. Attained when yogi constantly sees Paramatma in his (jivaatma) heart.
They are sometimes divided into the lower and the upper four limbs, the lower ones—from yama to pranayama—being parallel to the lower limbs of hatha yoga, while the upper ones—from pratyahara to samadhi—being specific for the rāja yoga. The upper three limbs practiced simultaneously constitute the samyama.

  Yama: Yama (restraints) consists of five parts: ahimsa (non-violence), satya (truthfulness), asteya (non-stealing), brahmacharya (sexual abstinence), and aparigraha (non-covetousness). Ahimsa is perfect harmlessness, as well as positive love. The five directives of yama lay down behavioral norms as prerequisites for elimination of fear, and contribute to a tranquil mind.

  Niyama: Niyama is observance of five canons: shaucha (internal and external purity), santosha (contentment), tapas (austerity), svadhyaya (study of religious books and repetitions of mantras), and ishvarapranidhana (self-surrender to God and his worship). Niyama, unlike uama, prescribes mental exercises to train the mind to control emotions.

Asana: Asana in the sense of a posture that one can hold for a period of time, staying relaxed and with normal (calm) breathing (or, as some sources say, "without effort").
In English, the Sanskrit word asana means "seat", the place where one sits; or posture, position of the body (any position). Asanas (in the sense of Yoga "posture") are said to derive from the various positions of animals' bodies (whence are derived most of the names of the positions). 84 asanas are considered to be the main postures, of which the highest are Shirshasan (headstand) and Padmasan (lotus).
The practice of asanas affects the following aspects or planes of the human being:
Physical (blood circulation, inner organs, glands, muscles, joints and nerve system)
Psychological (developing emotional balance and stability, harmony)
Mental (improved ability to concentrate, memory)
Consciousness (purifying and clarifying consciousness/awareness)
From the rāja yoga perspective, it is considered that the physical postures and pranayama serve to prepare the body and mind for the following steps: pratyahara, dharana, dhyana and samādhi (withdrawal of the senses, contemplation, meditation, and state of expanded or transcendental consciousness, where the activity of the mind ceases and "The Knower and The Object of Knowledge Become One").

Praṇayama: Praṇayama is made out of two Sanskrit words (praṇa = life energy; ayama = control or modification). Breathing is the medium used to achieve this goal. The mind and life force are correlated to the breath. Through regulating the breathing and practicing awareness on it, one learns to control prana.
According to Raja yoga, there are three main types (phases, units, stadia) of pranayama:
Purak (inhalation)
Rechak (exhalation)
Kumbhak (holding the breath); which appears as:
Antara kumbhak (withholding the breath after inhalation)
Bahar kumbhak (withholding the breath after exhalation)
Keval kumbhak (spontaneous withholding of the breath)
There are numerous techniques of pranayama, each with their specific goals. The main techniques are:
Surya Bhedana
Candra Bhedana
Nadi Shodhana (anuloma viloma)
Bhastrika
Kapalabhati
Ujjayi
Plavini (bhujangini)
Bhramari
Sheetkari
Sheetali
Murccha
All pranayama practice ultimately works toward purification of the nadis (energy channels) and the awakening of kundalini shakti at the muladhara chakra. The awakening of kundalini energy (also described as the awakening of divine consciousness or wisdom), and its ascent to the crown chakra is the final goal of rāja yoga.

  Pratyahara: Pratyahara is bringing the awareness to reside deep within oneself, free from the senses and external world. The Goal of Pratyahara is not to disrupt the communication from the sense organ to the brain. The awareness is far removed from the five senses. Pratyahara cannot be achieved without achievement of the preceding limbs (pranayama, niyama, etc.). The awareness comes to rest deep in the inner space, and during this time the yogi's breath will be temporarily suspended. Pratyahara should not just be likened to concentration or meditation, etc. It is a yogic practice that takes on adequacy with the prior 4 limbs as prerequisites.

  Dharana: Yoga starts from concentration. Concentration merges into meditation. Meditation ends in samadhi. Retention of breath, brahmacharya, satvic (pure) food, seclusion, silence,satsanga (being in the company of a guru), and not mixing much with people are all aids to concentration. Concentration on bhrakuti (the space between the two eyebrows) with closed eyes is preferred. The mind can thus be easily controlled, as this is the seat for the mind.

 Dhyana: In Dhyana, the meditator is not conscious of the act of meditation (i.e. is not aware that s/he is meditating) but is only aware that s/he exists (consciousness of being), and aware of the object of meditation. Dhyana is distinct from Dharana in that the meditator becomes one with the object of meditation. This means that the meditator although aware of the object through meditation detaches him/erself from its existence in the physical world. Much like meditation focused on the breath Dhyana is rooted in the concentration of not being concentrated.
The final stage of meditation in dhyāna is considered to be jhāna. At this stage of meditation, one does not see it as a meditational practice, but instead merges with the idea and thought. One cannot reach a higher stage of consciousness without jhāna.

 Samadhi: Meditation on Om with bhava removes obstacles in sadhana and helps to attain samadhi. Avidya (ignorance), asmita (egoism), raga-dvesha (likes and dislikes), abhinivesha(clinging to mundane life) are the five kleshas or afflictions.
Samadhi is of two kinds:
Savikalpa, samprajnata or sabija; and
Nirvikalpa, asamprajnata or nirbija.
In savikalpa or sabija, there is triputi or the triad (knower, known and knowledge). Savitarka, nirvitarka, savichara, nirvichara, sasmita and saananda are the different forms of savikalpa samadhi. In nirvikalpa samadhi, nirbija samadhi or asamprajnata samadhi there is no triad.

In the last sutra , Patañjali says the soul reaches its end in liberation, enlightenment, kaivalya.