astronomy

Wheel of time

Wheel of time 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 Wheel of time rather than just read about it. In short: The wheel of time or wheel of history (also known as Kalachakra) is a concept found in several religious traditions and philosophies, notably religions of Indian origin such as Hinduism, Jainism, and Buddhism, which regard time as cyclical and consisting of repeating ages. Many other cultures contain belief in a similar concept: notably, the Q'ero people of Peru, the Hopi people of Arizona, and the Bakongo people of…

Key takeaways

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

Reference excerpt

The wheel of time or wheel of history (also known as Kalachakra) is a concept found in several religious traditions and philosophies, notably religions of Indian origin such as Hinduism, Jainism, and Buddhism, which regard time as cyclical and consisting of repeating ages. Many other cultures contain belief in a similar concept: notably, the Q'ero people of Peru, the Hopi people of Arizona, and the Bakongo people of Angola and Democratic Republic of the Congo.

Ancient Africa

In traditional Bakongo religion, the four elements are incorporated into the Kongo cosmogram. This sacred wheel depicts the physical world (Nseke), the spiritual world of the ancestors (Mpémba), the Kalûnga line that runs between the two worlds, the sacred river (mbûngi) that began as a circular void and forms a circle around the two worlds, and the path of the sun. Each element correlates to a period in the life cycle, which the Bakongo people also equate to the four cardinal directions and seasons. According to their cosmology, all living things go through this cycle.

Mbûngi represents aether and is the void that exists before creation. Musoni time (South) represents air and is the period of conception that takes place during spring. Kala time (East) represent fire and is the period of birth that takes place during summer. Tukula time (North) represents earth and is the period of maturity that takes place during fall. Luvemba time (West) represents water and is the period of death that takes place during winter.

Ancient Rome The philosopher and emperor Marcus Aurelius saw time as extending forwards to infinity and backwards to infinity, while admitting the possibility (without arguing the case) that "the administration of the universe is organized into a succession of finite periods".

Buddhism

The Wheel of Time or Kalachakra is a Tantric deity that is associated with Tibetan Tantric Buddhism, which encompasses all four main schools of Sakya, Nyingma, Kagyu and Gelug, and is especially important within the lesser-known Jonang tradition. The Kalachakra tantra prophesies a world within which (religious) conflict is prevalent. A worldwide war will be waged which will see the expansion of the mystical Kingdom of Shambhala led by a messianic king.

Hinduism

In Hindu cosmology, kala (time) is eternal, repeating general events in four types of cycles. The smallest cycle is a maha-yuga (great age), containing four yugas (dharmic ages): Satya Yuga, Treta Yuga, Dvapara Yuga and Kali Yuga. A manvantara (age of Manu) contains 71 maha-yugas. A kalpa (day of Brahma) contains 14 manvantaras and 15 sandhyas (connecting periods), which lasts for 1,000 maha-yugas and is followed by a pralaya (night of partial dissolution) of equal length, where a day and night make one full day. A maha-kalpa (life of Brahma) lasts for 100 of Brahma's years of 12 months of 30 full days (100 360-day years) or 72,000,000 maha-yugas, which is followed by a maha-pralaya (full dissolution) of equal length.

Jainism

Within Jainism, time is thought to be a wheel that rotates for infinity without a beginning. This wheel of time holds twelve spokes that each symbolize a different phase in the universe's cosmological history. It is further divided into two equal halves having six eras in them. While in a downward motion, the wheel of time falls into what is known as Avasarpiṇī and when in an upward motion, enters a state called Utsarpini. During both motions of the wheel, 24 tirthankaras come forth to teach the three jewels or sacred Jain teachings of right faith, right knowledge, and right practice, then create a spiritual ford across the ocean of rebirth for humanity.

Modern usage

Literature In an interview included with the audiobook editions of his novels, author Robert Jordan has stated that his bestselling fantasy series The Wheel of Time borrows the titular concept from Hindu mythology. The first chapter of every book in the series begins with the lines: "The Wheel of Time turns, and ages come and pass, leaving memories that become legend. Legends fade to myth, and even myth is long forgotten when the Age that gave it birth comes again."

See also Eternal return Wheel of the Year

References

Sources Jordan, Robert (1990). The eye of the world. New York: T. Doherty Associates. ISBN 0-312-85009-3.

Illustrations

Worked examples

Example 1 — a first encounter with Wheel of time

Start with the simplest possible case. Write down what Wheel of time 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 Wheel of time 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 Wheel of time 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 Wheel of time

In research: Wheel of time 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 Wheel of time 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: Wheel of time is common in secondary-school and first-year university syllabi. It links to neighbouring topics Buddhist cosmology, Hindu philosophical concepts, Jain cosmology, so understanding it makes those chapters shorter.
In everyday life: Look for Wheel of time 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 Wheel of time in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Wheel of time 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 Wheel of time out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Wheel of time in simple terms?

Why does Wheel of time 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 Wheel of time?

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 Wheel of time.