The phenomenon where the spirit within a body can be separated from the physical body and can be led to travel to higher astral planes, is called astral travelling. Thus it is a method of projecting the soul out of the body and sending it to high celestial planes and in the world of consciousness, where the surroundings can be observed from afar.
Astral travelling is a very old phenomenon. The spiritual 'sanyasis' who resided in lonely mountain caves and belonged to old and spiritually advanced cultures of India ,Egypt and the like , were believed to go onto trances and go wherever they wanted.
Astral travelling may be experienced at a time of near death instances or at the time of lucid dreaming. For example, survivors of road accidents or drowning have given accounts of seeing their own accidents beforehand, as if seen in a movie.
Astral travelling is usually experienced at the time of lucid dreams or Meditational trances. Lucid dreaming is the act of passing into the world of dreams with a focused and awake mind state. This is why, when a person is fully conscious of his dreaming, he is said to be having lucid dreams, where he leaves his physical body to travel into other consciousness layers.
It is difficult to achieve astral travelling since a very high degree of control on one's sub conscious mind is required which one can only be attained through intense Meditational practices. For astral travelling, it is necessary that you arrange for a calm and peaceful environment beforehand, free of any electronic device. Be aware of your food intake before such an attempt since non vegetarian food or things such as caffeine increases body heat and multiply thoughts in one's mind and hence should be avoided. Moreover, your mind should be free from all negative thoughts.
Astral travelling can be achieved by attaining a deep trance like state through basic Meditational practices. Essentially you should try to mimic the REM sleep mode which is the last phase of our sleep cycle characterized by rapid eye movement and intense brain activity. Relax your body so as to make it go to sleep while intensely concentrating to keep your mind wakeful and focused. Visualize yourself floating out of your body or use a prop like a rope to see yourself climb out if required and direct all your energies to energize this vision in order to manifest it in reality.
Getting out from the body is the primary problem faced during astral travelling. Even if there is the smallest of doubts in your mind, you will be stuck in your body. You should have complete unhindered faith in yourself to achieve the desired goal. If you are in constant thought and doubt of your actions in leaving the body, you may actually fail in doing so.
The second problem arises when you have managed to leave your body and travelling outwards. You should remember that even the slightest of fears in the mind that whether you are going to get too far away or not, or weather you can return back, will cause yourself to be ' sucked in' into your physical being once again, and you'll wake up all of a sudden. Thus, the main thing is to be clam, fearless and peaceful and have faith and believe in yourself to enjoy and experience astral travelling. | 
