A map of existence, not a map of the sky
Buddhist cosmology is the traditional picture of how the universe is arranged and where beings can be reborn. It developed in the centuries after the Buddha, mainly in Indian texts, and was then adapted in each Buddhist region. It is a framework for understanding karma and rebirth rather than a scientific model, and it should not be read as a rival to modern astronomy. Astronomy describes physical space, stars and galaxies as measured by observation. Buddhist cosmology describes states of existence and how actions are said to shape them.
Many Buddhists today treat the traditional picture as literal, some treat it as symbolic or psychological, and many hold a mixture of both views. A calm approach is to read it as a tradition with its own aims, not as a scientific claim.
The three spheres
Early Buddhist texts organise existence into three broad spheres.
- The desire realm (kamaloka), where beings are driven by wants and aversions. It includes hell realms, hungry ghosts, animals, humans, demigods and the lower heavens.
- The form realm (rupaloka), higher heavens linked to refined states of meditative absorption.
- The formless realm (arupaloka), the most subtle states, associated with the highest absorptions.
Counting differs. Theravada sources often list thirty-one planes of existence across the three spheres, while Mahayana and Vajrayana texts commonly present variant lists. Texts also differ on names and on the order of some heavens, so a figure given in one tradition may not match another.
The six realms of rebirth
In Tibetan, Chinese, Korean and Japanese traditions, a simplified scheme of six realms is very common: gods, demigods (asuras), humans, animals, hungry ghosts and hell beings. Theravada texts also discuss these states, though the sixfold diagram is more prominent in Mahayana and Vajrayana art. Rebirth in any of them is understood to be impermanent, and the human realm is often described as a fortunate one because it offers the chance to practise. This is the scheme painted in the Wheel of Life mural, which many visitors see in Tibetan monasteries.
Mount Meru and the world system
Many Indian texts describe a world with a great central mountain, Mount Meru (Sumeru), surrounded by concentric rings of seas and mountains and four continents. The Abhidharmakosa, a text associated with the fourth-to-fifth-century thinker Vasubandhu, gives a systematic account that became influential in Tibet and East Asia. Mount Meru symbolism appears in temple design, in some stupa forms and in the mandala offering. Borobudur and some Southeast Asian temples are sometimes interpreted as reflecting such a vision, though scholars differ about how closely.
Beyond a single world system, the texts speak of enormous numbers of world systems, grouped into a thousand-fold, two-thousand-fold and three-thousand-fold great universe. These numbers are used to convey vastness rather than to give measurements.
Time in cycles
Cosmic time is measured in kalpas, vast cycles of formation, abiding, decline and dissolution. The texts give very large figures, often by analogy; one traditional comparison describes a kalpa through the image of a mountain worn away by a cloth brushing it at long intervals. Different texts give different calculations, so there is no single agreed length.
Buddhist astronomy and calendars
Separate from cosmology is the practical study of the sky. Buddhist societies have long used lunar calendars to fix festivals and observance days, and in Tibet, Bhutan, Mongolia and elsewhere there are astrological traditions, such as those connected with the Kalachakra teachings, that are used to calculate calendars. In Burma, the planetary posts around the Shwedagon Pagoda reflect a local tradition linking weekdays with planets and animals. These systems draw on Indian, Chinese and local sources, and they are cultural practices rather than doctrines required of all Buddhists.
Cosmology and science
Some modern Buddhist teachers and scholars hold that the traditional picture was a product of its time and that the core teachings, such as impermanence and dependent origination, do not depend on it. Others value the cosmology as part of the tradition’s heritage. Both responses are common. If you speak with monks or teachers, expect a range of views and avoid assuming one position.
Seeing cosmology at pilgrimage sites
You will meet these ideas in practical ways:
- murals and mandalas that show realms, Mount Meru or the Wheel of Life;
- temple halls arranged to evoke heavens or sacred mountains;
- stupas whose levels are explained as stages of a path;
- offering rituals that symbolically present the universe.
Guides and monks at a site can explain what a particular image shows, though their explanations will reflect their tradition. Photography rules for murals vary, and you should ask before using a camera.
Reading with care
Because the sources are old and varied, many details are uncertain or contested. When a guide book or website gives precise numbers for heavens, hells or ages, check which text it relies on. Where texts disagree, the honest answer is often that traditions differ.