Astral travel is a paranormal interpretation of an out-of-body experience achieved either awake or via lucid dreaming or deep meditation. The concept of astral projection assumes the existence of another body, separate from the physical body and capable of traveling to non-physical planes of existence. Commonly such planes are called astral, etheric, or spiritual. Astral projection is often experienced as the spirit or astral body leaving the physical body to travel in the spirit world or astral plane. Astral projection is controversial. Skeptics say that there is only anecdotal evidence that anything actually leaves the body.