astronomy

Per Barth Lilje

Per Barth Lilje 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 Per Barth Lilje rather than just read about it. In short: Per Vidar Barth Lilje (born 11 March 1957) is a Norwegian astronomer. He was born in Tønsberg.

Key takeaways

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

Reference excerpt

Per Vidar Barth Lilje (born 11 March 1957) is a Norwegian astronomer. He was born in Tønsberg. He took his Ph.D. at the University of Cambridge in 1988, and worked at the Nordic Institute for Theoretical Physics from 1989 to 1992. He became professor at the University of Oslo in 1993, and previously headed the Institute of Theoretical Astrophysics there. His fields are cosmology and extragalactic astronomy. In 2017 he was inducted into the Norwegian Academy of Science and Letters.

References

External links List of publications by Per Barth Lilje in CRIStin

Worked examples

Example 1 — a first encounter with Per Barth Lilje

Start with the simplest possible case. Write down what Per Barth Lilje 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 Per Barth Lilje 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 Per Barth Lilje 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 Per Barth Lilje

In research: Per Barth Lilje 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 Per Barth Lilje 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: Per Barth Lilje is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1957 births, Academic staff of the University of Oslo, Alumni of the University of Cambridge, so understanding it makes those chapters shorter.
In everyday life: Look for Per Barth Lilje 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 Per Barth Lilje in 20 minutes

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

Frequently asked questions

What is Per Barth Lilje in simple terms?

Per Vidar Barth Lilje (born 11 March 1957) is a Norwegian astronomer. He was born in Tønsberg.

Why does Per Barth Lilje 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 Per Barth Lilje?

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 Per Barth Lilje.