astronomy

Yāma

Yāma is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Yāma rather than just read about it. In short: Yāma is the third of the six heavenly worlds of the desire realm in Buddhist cosmology. It is located between Trāyastriṃśa and Tushita.

Key takeaways

Yāma belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Yāma to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Yāma from memory before moving on to harder problems.

Reference excerpt

Yāma is the third of the six heavenly worlds of the desire realm in Buddhist cosmology. It is located between Trāyastriṃśa and Tushita. This world is variously translated as "wonderful times", "virtuous", "excellent times" or "of the hours." It is said that the Yāma heaven is always illuminated so that there is no division of day and night. The gods here enjoy satisfaction of the five desires, which arise in relation to the five sense organs.

Etymology Yāma is a Sanskrit technical term referring to a measurement of time, similar to a "watch" in English. A 24-hour day is divided into eight three-hour "watches", which makes a yāma equal to 1/4 of a day or night. An equivalent unit of time is a prahar, which is synonymous with the modern pahar. A Chinese text referred to as the Sse-kiau-tsih reads that the gods of this world distinguish time by the opening and shutting of flowers. There are several Chinese translations / kanji transcriptions of the name Yāma, including but not limited to 焰摩天, 夜摩天, 唱樂天, 時分天, and 炎魔.

Descriptions Yāma is the first heaven that functions as a disconnect between the swarga heavens (Heavens in which Devas can interact with humans) and the human realm. The deities here are not involved in conflict with the asuras due to them being positioned above Tāvatiṁsa on Mount Meru and are said to "have arrived at divine bliss" (dibbaṃ sukhaṃ) (Vibh-a 18:6,1). According to the Visakhuposatha Sutta of the Pāli Canon, time there runs very differently than on Earth: "That which among men is two hundred years...is one night and day of the Yāma devas, their month has thirty of those days, their year twelve of those months; the lifespan of the Yāma devas is two thousand of those heavenly years." A month in this world may be calculated to be 6,000 human years. A Yāma deva year is 72,000 years, and a Yāma deva lifespan is 144,000,000 years. According to the Dāna Sutta, those who practice generosity with the intention of continuing a family custom of such deeds create the karmic conditions to be reborn in Yāma Heaven.

Mahāyāna The Amitāyurdhyāna Sūtra provides a few further details. Yāma Heaven includes the river Jambū, and a celestial palace that features a canopy decorated with five hundred million jewels, compared with that found in Amitābha's Pure Land. According to the Avataṃsaka Sūtra in 60 fascicles, bodhisattvas of the fourth stage may become the ruler of this heaven.

See also Yama (Buddhism) - An arguably unrelated deity in the Buddhist pantheon Third Heaven

References

Worked examples

Example 1 — a first encounter with Yāma

Start with the simplest possible case. Write down what Yāma claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Yāma before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Yāma ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Yāma

In research: Yāma appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Yāma in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Yāma is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buddhist cosmology, so understanding it makes those chapters shorter.
In everyday life: Look for Yāma outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Yāma in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Yāma means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Yāma out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Yāma in simple terms?

Yāma is the third of the six heavenly worlds of the desire realm in Buddhist cosmology. It is located between Trāyastriṃśa and Tushita.

Why does Yāma matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Yāma?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Yāma.