astronomy

John W. Valley

John W. Valley 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 John W. Valley rather than just read about it. In short: John Williams Valley (born February 28, 1948, in Winchester, Massachusetts) is an American geochemist and petrologist. He is an expert on stable isotope geochemistry, especially as applied to understanding the evolution of the Earth's crust.

Key takeaways

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

Reference excerpt

John Williams Valley (born February 28, 1948, in Winchester, Massachusetts) is an American geochemist and petrologist. He is an expert on stable isotope geochemistry, especially as applied to understanding the evolution of the Earth's crust.

Biography Valley grew up in Lexington, Massachusetts, and started collecting rocks when he was four years old. He studied geology at Dartmouth College (AB 1970) and at the University of Michigan (MS 1977, PhD 1980) He was an assistant professor at Rice University (1980-1983) before moving to the University of Wisconsin, Madison, where he was an assistant professor (1983-1985), associate professor (1985-1989), and full professor from 1989 until his retirement in 2019 as professor emeritus. In 2005 he was appointed Charles R. Van Hise Distinguished Professor. He was a Fulbright Scholar at the University of Edinburgh (1989-1990). His doctoral students include Claudia Mora, Jean Morrison, and John Eiler. Valley is an expert on stable isotope geochemistry applied to metamorphic, igneous and sedimentary rocks. He has worked extensively on high-grade metamorphic Precambrian rocks, especially in the Grenville Province of New York and Canada. He and his colleagues investigated the Sierra Nevada batholith, lavas from Pacific islands, and rhyolites from the Yellowstone Plateau Volcanic Field. Valley has studied numerous proxies for paleoclimate including speleothems, mollusks, foraminifera, otoliths, pearls, and fossil teeth. He organized three conferences on applications of new SIMS technology to paleoclimatology (HiRes2013, 2015 and 2017).

Valley and others demonstrated that carbonates in the Martian meteorite Allan Hills 84001 formed at low temperatures, and that material from the comet 81P/Wild is chondrule-like indicating transport from the asteroid belt to the cold outer reaches of the Solar System. In 2001, Valley, with 3 co-workers, discovered the oldest known samples of Earth, detrital zircons from the Jack Hills in Western Australia, which document the existence of differentiated crust on Earth by 4.4 Ga (billion years ago) about 150 Myr (million years) after the Earth's formation at 4.55 Ga. The oxygen isotope ratios of these zircons indicate that the Earth cooled sooner, by over 600 Myr, than previous evidence indicated and that oceans were habitable to life by 4.3 Ga, 800 Myr earlier than the oldest well-documented micro-fossils. He has also shown, by a unique correlation of carbon isotope ratios (measured at micron-scale) to morphology, that these ancient fossils are indeed biogenic and lived in complex communities of microbial life 3,465 million years ago, indicating that the first life came earlier. Valley has been active in professional service. In 2005, he founded the Wisconsin Secondary Ion Mass Spectrometry Laboratory (WiscSIMS) to develop new methods for measuring stable isotopes in the nano to micrometer range. Over 400 scientists have now worked at WiscSIMS. He served on many committees for mineralogy, geochemistry, and geology, including the NRC Committee on the Scientific Context for the Exploration of the Moon (2007). From 2014 to 2023 he served on the board of governors for the Gemological Institute of America. He has been associate editor for the Geological Society of America Bulletin (1985-1991), the American Journal of Science (1996-) and the Proceedings of the National Academy of Sciences (2021-). From 2011 to 2015 he was an editor in chief for the journal Elements. He was the president of Mineralogical Society of America in 2005–2006. Valley was elected a Fellow of the Geological Society of America (GSA, 1992), the Mineralogical Society of America (MSA, 1993), the American Geophysical Union (AGU, 1996), the European Association of Geochemistry (2011), and the Geochemical Society (2011). AGU gave him the Norman L. Bowen Award in 2003 In 2019 GSA awarded him the Arthur L. Day Medal. In 2022 he received the Roebling Medal from MSA. He was elected a Member of the National Academy of Sciences in 2019. In 2017, the International Mineralogical Association (IMA) approved the name "valleyite" for the mineral Ca4Fe6O13, discovered by Huifang Xu and named in honor of John W. Valley. In 1972 Valley married Andrée Simone Taylor. They have two sons, Matthew and David. Valley is also a skilled woodworker. Before graduate school, he made furniture in Helena, Montana, while there with Andrée, who was Resident Artist at the Archie Bray Foundation for the Ceramic Arts. Andrée works extensively in metal and ceramic sculpture. Her work is displayed internationally.

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with John W. Valley

Start with the simplest possible case. Write down what John W. Valley 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 John W. Valley 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 John W. Valley 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 John W. Valley

In research: John W. Valley 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 John W. Valley 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: John W. Valley is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1948 births, American geochemists, American mineralogists, so understanding it makes those chapters shorter.
In everyday life: Look for John W. Valley 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 John W. Valley in 20 minutes

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

Frequently asked questions

What is John W. Valley in simple terms?

Why does John W. Valley 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 John W. Valley?

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 John W. Valley.