astronomy

Jan Woltjer (astronomer)

Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) rather than just read about it. In short: Jan Woltjer (3 August 1891, Amsterdam – 28 January 1946, Leiden) was a Dutch astronomer. Woltjer was the son of the classical scholar Jan Woltjer.

Key takeaways

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

Reference excerpt

Jan Woltjer (3 August 1891, Amsterdam – 28 January 1946, Leiden) was a Dutch astronomer. Woltjer was the son of the classical scholar Jan Woltjer. On 13 December 1916 he married Hillegonda de Vries in Groningen. He worked and taught at Leiden University, where Gerard P. Kuiper was one of his students. He was the father of the astronomer Lodewijk Woltjer (1930–2019), who was the director general of the European Southern Observatory from 1975 to 1987. The crater Woltjer on the Moon and the asteroid 1795 Woltjer are both named after him.

References

External links Website Leiden professors

Illustrations

Worked examples

Example 1 — a first encounter with Jan Woltjer (astronomer)

Start with the simplest possible case. Write down what Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer)

In research: Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) 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: Jan Woltjer (astronomer) is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1891 births, 1946 deaths, 20th-century Dutch astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer) out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Jan Woltjer (astronomer) in simple terms?

Jan Woltjer (3 August 1891, Amsterdam – 28 January 1946, Leiden) was a Dutch astronomer. Woltjer was the son of the classical scholar Jan Woltjer.

Why does Jan Woltjer (astronomer) 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 Jan Woltjer (astronomer)?

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 Jan Woltjer (astronomer).