astronomy

Jesse L. Greenstein

Jesse L. Greenstein 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 Jesse L. Greenstein rather than just read about it. In short: Jesse Leonard Greenstein (October 15, 1909 – October 21, 2002) was an American astronomer. His parents were Maurice G. and Leah Feingold.

Key takeaways

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

Reference excerpt

Jesse Leonard Greenstein (October 15, 1909 – October 21, 2002) was an American astronomer. His parents were Maurice G. and Leah Feingold. He earned a Ph.D, with thesis advisor Donald H. Menzel, from Harvard University in 1937, having started there at age 16. Before leaving Harvard, Greenstein was involved in a project with Fred Lawrence Whipple to explain Karl Jansky's discovery of radio waves from the Milky Way and to propose a source. He began his professional career at Yerkes Observatory under Otto Struve and later went to Caltech. With Louis G. Henyey he invented a new spectrograph and a wide-field camera, along with the Henyey-Greenstein phase function. He directed the Caltech astronomy program until 1972 and later did classified work on military reconnaissance satellites. With Leverett Davis, Jr, he demonstrated in 1949 that the magnetic field in our galaxy is aligned with the spiral arms. His theoretical work with Davis was based on the conclusion just reached by William A. Hiltner that the recently detected polarization of starlight was due to dichroic extinction by interstellar dust grains aligned with the ambient magnetic field. For the 1965 book Galactic Structure, edited by Blaauw and Schmidt, Greenstein wrote an important chapter on subluminous blue stars. Greenstein did important work in determining the abundances of the elements in stars, and was, with Maarten Schmidt, among the first to recognize quasars as compact, very distant sources as bright as a galaxy. The spectra of the first quasars discovered, radio sources 3C 48 and 3C 273, were displaced so far to the red due to their redshifts as to be almost unrecognizable, but Greenstein deciphered 3C 48 shortly before Schmidt, his colleague at the Hale Observatories worked out the spectrum of 3C 273.

Honors Awards

Henry Norris Russell Lectureship of the American Astronomical Society (1970) Bruce Medal (1971) Gold Medal of the Royal Astronomical Society (1975) Golden Plate Award of the American Academy of Achievement (1980)

Honors Elected to the American Academy of Arts and Sciences (1954) Elected to the United States National Academy of Sciences (1957) Elected to the American Philosophical Society (1968) Named after him

Asteroid 4612 Greenstein

References

External links Obituary from Caltech Caltech oral history interview Story of the discovery of quasars Bruce Medal page Archived 2020-01-29 at the Wayback Machine Awarding of Bruce medal: PASP 83 (1971) 243 Awarding of RAS gold medal: QJRAS 16 (1975) 356 Biography by Robert P. Kraft, former director of Lick Observatory

Worked examples

Example 1 — a first encounter with Jesse L. Greenstein

Start with the simplest possible case. Write down what Jesse L. Greenstein 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 Jesse L. Greenstein 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 Jesse L. Greenstein 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 Jesse L. Greenstein

In research: Jesse L. Greenstein 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 Jesse L. Greenstein 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: Jesse L. Greenstein is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1909 births, 2002 deaths, American astronomers, so understanding it makes those chapters shorter.
In everyday life: Look for Jesse L. Greenstein 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 Jesse L. Greenstein in 20 minutes

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

Frequently asked questions

What is Jesse L. Greenstein in simple terms?

Jesse Leonard Greenstein (October 15, 1909 – October 21, 2002) was an American astronomer. His parents were Maurice G. and Leah Feingold.

Why does Jesse L. Greenstein 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 Jesse L. Greenstein?

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 Jesse L. Greenstein.