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astronomy

Johann Radon

Johann Radon 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 Johann Radon rather than just read about it. In short: Johann Karl August Radon ([ˈʁaːdɔn]; 16 December 1887 – 25 May 1956) was an Austrian mathematician. His doctoral dissertation was on the calculus of variations (in 1910, at the University of Vienna).

Johann Radon — main illustration
Johann Radon — illustration

Key takeaways

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

Reference excerpt

Johann Karl August Radon ([ˈʁaːdɔn]; 16 December 1887 – 25 May 1956) was an Austrian mathematician. His doctoral dissertation was on the calculus of variations (in 1910, at the University of Vienna).

Life Radon was born in Tetschen, Bohemia, Austria-Hungary, now Děčín, Czech Republic. He received his doctoral degree at the University of Vienna in 1910. He spent the winter semester 1910/11 at the University of Göttingen, then he was an assistant at the German Technical University in Brno, and from 1912 to 1919 at the Technical University of Vienna. In 1913/14, he passed his habilitation at the University of Vienna. Due to his near-sightedness, he was exempt from the draft during wartime. In 1919, he was called to become Professor extraordinarius at the newly founded University of Hamburg; in 1922, he became Professor ordinarius at the University of Greifswald, and in 1925 at the University of Erlangen. Then he was Ordinarius at the University of Breslau from 1928 to 1945. After a short stay at the University of Innsbruck he became Ordinarius at the Institute of Mathematics of the University of Vienna on 1 October 1946. In 1954/55, he was rector of the University of Vienna. In 1939, Radon became corresponding member of the Austrian Academy of Sciences, and in 1947, he became a member. From 1952 to 1956, he was Secretary of the Class of Mathematics and Science of this Academy. From 1948 to 1950, he was president of the Austrian Mathematical Society. Johann Radon married Maria Rigele, a secondary school teacher, in 1916. They had three sons who died young or very young. Their daughter Brigitte (1924–2020) obtained a Ph.D. in mathematics at the University of Innsbruck and married the Austrian mathematician Erich Bukovics in 1950. Radon, as Curt C. Christian described him in 1987 at the occasion of the unveiling of his brass bust at the University of Vienna, was a friendly, good-natured man, highly esteemed by students and colleagues alike, a noble personality. He did make the impression of a quiet scholar, but he was also sociable and willing to celebrate. He loved music, and he played music with friends at home, being an excellent violinist himself, and a good singer. His love for classical literature lasted through all his life. In 2003, the Austrian Academy of Sciences founded an Institute for Computational and Applied Mathematics and named it after Johann Radon (see the external link below).

Achievements Radon is known for a number of lasting contributions, including:

his part in the Radon–Nikodym theorem; the Radon measure concept of measure as linear functional; the Radon transform, in integral geometry, based on integration over hyperplanes—with application to tomography for scanners (see tomographic reconstruction); Radon's theorem, that d + 2 points in d dimensions may always be partitioned into two subsets with intersecting convex hulls; the Radon–Hurwitz numbers. He is possibly the first to make use of the so-called Radon–Riesz property.

See also Radon spaces Radonifying function

References

External links

O'Connor, John J.; Robertson, Edmund F., "Johann Radon", MacTutor History of Mathematics Archive, University of St Andrews Johann Radon at the Mathematics Genealogy Project Johann Radon Institute for Computational and Applied Mathematics (RICAM)

Illustrations

Johann Radon illustration

Worked examples

Example 1 — a first encounter with Johann Radon

Start with the simplest possible case. Write down what Johann Radon 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 Johann Radon 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 Johann Radon 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 Johann Radon

In research
Johann Radon 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 Johann Radon 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
Johann Radon is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1887 births, 1956 deaths, 20th-century Austrian mathematicians, so understanding it makes those chapters shorter.
In everyday life
Look for Johann Radon 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 Johann Radon in 20 minutes

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

Frequently asked questions

What is Johann Radon in simple terms?

Johann Karl August Radon ([ˈʁaːdɔn]; 16 December 1887 – 25 May 1956) was an Austrian mathematician. His doctoral dissertation was on the calculus of variations (in 1910, at the University of Vienna).

Why does Johann Radon 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 Johann Radon?

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 Johann Radon.

Tags

  • 1887 births
  • 1956 deaths
  • 20th-century Austrian mathematicians
  • Academic staff of TU Wien
  • Academic staff of the University of Breslau
  • Academic staff of the University of Erlangen-Nuremberg
  • Academic staff of the University of Greifswald
  • Academic staff of the University of Hamburg
  • Academic staff of the University of Innsbruck
  • Academic staff of the University of Vienna
  • Burials at Döbling Cemetery
  • Functional analysts

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