How vast is the range of the Trichiliocosm?

To understand this sutra, one must first grasp the concept of a Buddha-land. When texts refer to hundreds of billions of Buddha-lands, you must first understand what a single Buddha-land is: a trichiliocosm, the realm taught and guided by a single Buddha.

How vast is a trichiliocosm? We begin with its smallest unit: the caturdvipa, literally “four continents.” A caturdvipa is centered on Mount Sumeru, which stands 84,000 yojanas tall and is composed of gold, silver, lapis lazuli, and crystal.

At the mid-level of Mount Sumeru, the sun and moon orbit around it. At the four cardinal directions around the mountain lie the four great continents: we dwell on the southern side of Mount Sumeru in Jambudvipa (the Southern Jambu Continent), alongside Uttarakuru (the Northern Kuru Continent), Aparagodaniya (the Western Ox-herding Continent), and Purvavideha (the Eastern Divine Continent). Buddhist scriptures provide detailed accounts of the physical forms, lifespans, karmic fortune, political systems, economies, and ecologies of the beings inhabiting these four continents.

Outside Mount Sumeru are seven concentric layers of fragrant seas, each separated by a ring of mountains—seven alternating layers of seas and mountains in total. The outermost layer is enclosed by a great iron encircling mountain, solid and fine as wrought iron. The Mount Sumeru and four great continents enclosed by this great iron encircling mountain together constitute a caturdvipa, the smallest unit of a trichiliocosm.

One thousand such caturdipas constitute a small chiliocosm, covered by the three heavens of the first (and second) dhyana. One thousand small chiliocosms constitute a medium chiliocosm, covered by the heavens of the second (and third) dhyana. One thousand medium chiliocosms constitute a large chiliocosm, surmounted by the four dhyana heavens and the four formless realms. Thus, a single trichiliocosm contains tens of billions of Mount Sumerus, tens of billions of seas, and tens of billions of iron encircling mountains. This is an astronomical-scale concept, and we cannot possibly fathom the full extent of these realms. Even setting aside the tens of billions of Mount Sumerus, modern astronomers cannot confirm the existence of even one Mount Sumeru, having never been able to detect it. Since they cannot detect it, some dismiss it as mere myth.

However, it is important to note that modern astronomers have also found the universe to be far more mysterious than once thought. The material substances observable with their instruments are extremely limited, while the vast majority of the universe remains unobservable. This has led scientists to propose the concept of dark matter: matter undetectable by their current instruments. Scientists estimate that observable matter comprises only 4% of the universe’s total mass, while 96% consists of undetectable dark matter. This is a far more objective view.

Can we really jump to conclusions about regions we cannot observe, and declare that Mount Sumeru does not exist? We sentient beings are like frogs at the bottom of a well, with only a narrow, limited view of reality. The full extent of the entire dharma realm can only be directly perceived by the Buddha, who possesses the perfect fivefold vision. As Buddhist practitioners, we should trust the Buddha’s teaching of the trichiliocosm, even if we cannot yet locate Mount Sumeru. Even modern astronomy, which studies phenomena such as black holes, cannot fully fathom these mysteries. There are countless black holes in the universe, with gravitational pulls so strong that not even light can escape them. It is entirely possible that Mount Sumeru is composed of four extremely subtle substances undetectable by the observational instruments of our world.

If we look further into the Ocean of the Huazang Buddha-realms described in the Avatamsaka Sutra, we see that this Ocean of Huazang Realms is itself a single unit within the entire dharma realm, and there are countless other worlds just like it. This reveals just how narrow and short-sighted our small minds truly are; we must expand our capacity to comprehend such vast truths. To reiterate: a single Buddha-land is a trichiliocosm, and a single trichiliocosm is the realm taught and guided by one Buddha.

For instance, Shakyamuni Buddha teaches within just one such trichiliocosm. He not only manifests the eight stages of enlightenment in Jambudvipa, but does so simultaneously in tens of billions of Jambudvipas. Furthermore, he does not only manifest enlightenment in the Saha World, but also in countless other worlds beyond it. You can only fully understand this by reading the Avatamsaka Sutra—it is truly extraordinary. Finally, a single Buddha-land undergoes the four stages of formation, abiding, decay, and emptiness, with four intermediate kalpas comprising one great kalpa.