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astronomy

Peter Goldreich

Peter Goldreich 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 Peter Goldreich rather than just read about it. In short: Peter Goldreich (born July 14, 1939) is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology.

Peter Goldreich — main illustration
Peter Goldreich — illustration

Key takeaways

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

Reference excerpt

Peter Goldreich (born July 14, 1939) is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology. Since 2005 he has also been a professor at the Institute for Advanced Study in Princeton, New Jersey. Asteroid 3805 Goldreich is named after him.

Career Goldreich received a bachelor of science in engineering physics from Cornell University in 1960, and obtained a Ph.D. from Cornell in 1963 under the supervision of Thomas Gold. In 1963 and 1964 Goldreich was a postdoctoral fellow at Cambridge University. From 1964 to 1966 he was an assistant professor of astronomy and geophysics at UCLA. Goldreich joined the faculty at Caltech in 1966 as an associate professor. He later became a full professor in 1969 while remaining at Caltech, and in 1981 he became the Lee A. DuBridge Professor of Astrophysics & Planetary Physics also at Caltech. He also sits on the Board of Adjudicators for the Shaw Prize, and the selection committee for Astronomy Prizes.

Scientific accomplishments Goldreich has made a wide range of significant contributions to theoretical astrophysics and planetary sciences. In 1966 Goldreich published a classic paper on the evolution of the Moon's orbit and on the orbits of other moons in the Solar System. He showed that for each planet there is a certain distance such that moons closer to the planet than that distance maintain an almost constant orbital inclination with respect to the planet's equator (with an orbital precession mostly due to the tidal influence of the planet), whereas moons further away maintain an almost constant orbital inclination with respect to the ecliptic (with precession due mostly to the tidal influence of the Sun). The moons in the first category, with the exception of Neptune's moon Triton, orbit near the equatorial plane. He concluded that these moons formed from equatorial accretion disks. But he found that the Moon, although it was once inside the critical distance from the Earth, never had an equatorial orbit as would be expected from various scenarios for its origin. This is called the lunar inclination problem, to which various solutions have since been proposed. Goldreich and Alar Toomre first described the process of polar wander in a 1969 paper, although evidence of paleomagnetism was not discovered until later. Goldreich collaborated with George Abell to conclude that planetary nebulae evolved from red giant stars, a view that is now widely accepted. In 1979 Goldreich, along with Scott Tremaine predicted that Saturn's F ring was maintained by shepherd moons, a prediction that would be confirmed by observations in 1980. They also predicted that Uranus' rings were held in place by similar shepherd moons, a prediction that was confirmed in 1986. Goldreich, along with Tremaine predicted planetary migration in 1980, which would later be invoked to explain hot jupiters. In 1969, Goldreich published a paper together with William Julian that is now considered a classic work on pulsar magnetospheres. They provided a simple and compelling model for the structure of magnetic fields anchored in a neutron star and showed that these fields can extract the neutron star rotational energy to power electromagnetic emission. Similar considerations were later used to understand the magnetospheres of rotating black holes.

Awards and honors Woodrow Wilson Honorary Fellowship, 1960–1961 Andrew Dixon White Fellowship, 1960–1961 National Foundation Fellowship, 1961–1963 National Academy of Sciences, National Research Council Postdoctoral Fellowship, 1963–1964 Sloan Foundation Fellowship, 1968–1970 Elected to National Academy of Sciences, 1972 Elected to American Academy of Arts and Sciences, 1973 Henry Norris Russell Lectureship of the American Astronomical Society, 1979 California Scientist of the Year, 1981 Chapman Medal of the Royal Astronomical Society, 1985 Brouwer Award of the Division on Dynamical Astronomy of the American Astronomical Society, 1986 Amos de Shalit Lecturer at the Weizmann Institute, 1986 Thomas Gold Lecturer at Cornell University, 1987 Regents Fellow, Smithsonian Institution, 1988–1990 Miller Professorship, University of California, Berkeley, 1990 Gerard P. Kuiper Prize of the Division for Planetary Science, American Astronomical Society, 1992 Morris Loeb Lecturer, Harvard University, 1992 Gold Medal of the Royal Astronomical Society, 1993 Foreign Member of the Royal Society, 2004 Shaw Prize, 2007 In 1995, Goldreich received the National Medal of Science for "his profound and lasting contributions to planetary sciences and astrophysics, providing fundamental theoretical insights for understanding the rotation of planets, the dynamics of planetary rings, pulsars, astrophysical masers, the spiral arms of galaxies, and the oscillations of the Sun". Goldreich was awarded the Grande Médaille of the French Academy of Sciences in 2006 for his numerous contributions in the field of Astrophysics. Goldreich received the 2007 Shaw Prize in Astronomy "in recognition of his lifetime achievements in theoretical astrophysics and planetary sciences".

References

External links Goldreich's website at the Institute for Advanced Study Scholarly Publications by Peter Goldreich

Illustrations

Peter Goldreich illustration

Worked examples

Example 1 — a first encounter with Peter Goldreich

Start with the simplest possible case. Write down what Peter Goldreich 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 Peter Goldreich 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 Peter Goldreich 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 Peter Goldreich

In research
Peter Goldreich 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 Peter Goldreich 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
Peter Goldreich is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1939 births, 20th-century American astronomers, 21st-century American Jews, so understanding it makes those chapters shorter.
In everyday life
Look for Peter Goldreich 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 Peter Goldreich in 20 minutes

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

Frequently asked questions

What is Peter Goldreich in simple terms?

Peter Goldreich (born July 14, 1939) is an American astrophysicist whose research focuses on celestial mechanics, planetary rings, helioseismology and neutron stars. He is the Lee DuBridge Professor of Astrophysics and Planetary Physics at California Institute of Technology.

Why does Peter Goldreich 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 Peter Goldreich?

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 Peter Goldreich.

Tags

  • 1939 births
  • 20th-century American astronomers
  • 21st-century American Jews
  • 21st-century American physicists
  • Academics of the University of Cambridge
  • American fellows of the Royal Society
  • California Institute of Technology faculty
  • Cornell University College of Engineering alumni
  • Foreign members of the Royal Society
  • Institute for Advanced Study faculty
  • Jewish American scientists
  • Living people

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