The plane humans live on, is the lowest of the higher realms of existence where one has the ability to comprehend the Dhamma. The Ābhāsvara worlds form the upper limits of existence. The scriptures talk about four tiers of existence or planes of consciousness. At the lowest level are the realms of Hell, and the worlds of Animal, hungry ghosts, & Asura / Titans. Above our world of Humans, there are the seven worlds of desire (Kama-lokas / Kamavacara). Above them are sixteen worlds of forms known as Ripa-lokas / Rupavacara. Above them are the four formless worlds (Arupa-lokas / Arupavacara).
Even on Earth, Buddhas are ALWAYS born in the middle kingdom. The following is what Buddha said of this region:
"Even if one escapes from the evil creations, it is one's rare fortune to be born as a human being. Even if one is born as a human, it is one's rare fortune to be born as a man and not a woman. Even if one is born as a man, it is one's rare fortune to be perfected in all the six senses. Even if he is perfected in all the six senses, it is his rare fortune to be born in the middle kingdom. Even if he is born in the middle kingdom, it is rare fortune to be born in the time of a Buddha. Even if he is born in the time of a Buddha, it is rare fortunate to see the Enlightened One. Even if he is able to see the Enlightened One, it is his rare fortune to have his heart awakened in faith. Even if he has faith, it is his rare fortune to awaken the heart of wisdom. Even if he awakens the heart of wisdom, it is his rare fortune to realise a spiritual state which is above discipline and attainment."
A Buddha’s birth, His Supreme Buddha-hood, His first Dhamma discourse, and His pass away (Parinibbāna) - all happen within this Middle Kingdom. We know of these details because of Buddha’s Ten Extra Ordinary Powers. One of the ten powers is that a Buddha is…
capable of seeing how He spent His past lives in many ways. He has the capability to remember His past lives in terms of one life, two lives, three lives, four lives, five lives, ten lives, twenty lives, thirty lives, forty lives, fifty lives, hundred lives, thousand lives, or even hundred thousand lives. In fact, He can remember the past up to infinite time such as many Sanvatta Kalpa, Vivatta Kalpa, and Sanvatta Vivatta Kalpa.
He is capable of remembering all the past lives with all related information in a manner as follows: “I lived in that particular place, in that name, and in that family name. My skin color was this. I ate these kinds of foods and felt these and these happiness and sorrow. I died in these ways and got born in that other place. I got that particular name in that life. I had this family name. My skin color was this. I ate these kinds of foods and felt these and these happiness and sorrow. I died in these ways and got born in that other place.”
