astronomy

H. Jay Melosh

H. Jay Melosh 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 H. Jay Melosh rather than just read about it. In short: H. Jay Melosh (June 23, 1947 – September 11, 2020) was an American geophysicist specialising in impact cratering.

Key takeaways

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

Reference excerpt

H. Jay Melosh (June 23, 1947 – September 11, 2020) was an American geophysicist specialising in impact cratering. He earned a degree in physics from Princeton University and a doctoral degree in physics and geology from Caltech in 1972. His PhD thesis concerned quarks. Melosh's research interests include impact craters, planetary tectonics, and the physics of earthquakes and landslides. His recent research includes studies of the giant impact origin of the Moon, the Chicxulub impact that is thought to have extinguished most dinosaurs, and studies of ejection of rocks from their parent bodies. He was active in astrobiological studies that relate chiefly to the exchange of microorganisms between the terrestrial planets (a process known as panspermia or transpermia). Melosh was a member of the American Geophysical Union, Geological Society of America, Meteoritical Society, American Astronomical Society (Division of Planetary Sciences,) and the American Association for the Advancement of Science. He was the recipient of the Barringer Medal of the Meteoritical Society for his work on the physics of impact, and of the G. K. Gilbert Award from the Geological Society of America. He was elected to the National Academy of Sciences in 2003.

Career Melosh took his first faculty role at Caltech between 1976 and 1979, where he researched the Moon's orientation in relation to mass concentrations (mascons) and large impacts, and was also a member of the GRAIL science team. He then went on to take a position with SUNY Stonybrook as an associate professor of geophysics until 1982 when he left to join the University of Arizona as a faculty member in the planetary sciences, where he continued work on impact cratering until 2009. In 2009, Dr. Melosh moved to the Purdue University Department of Earth, Atmospheric, and Planetary Sciences to study impact cratering, planetary science, and geophysics until his retirement.

Awards and honors Asteroid 8216 Melosh is named in his honor. The American Geophysical Union 2008 Harry H. Hess Medal - for “outstanding achievements in research in the constitution and evolution of Earth and sister planets.” In 2024 Melosh Crater was named after him in his honor. The crater is located near the Aram Chaos terrain in the equatorial region of Mars. The crater is almost 100 km in diameter and has a history of lava infilling and water flooding.

Publications H. J. Melosh (1989). Impact cratering: A geologic process. Oxford University Press. Bibcode:1989icgp.book.....M. ISBN 0-19-510463-3. LCCN 88005353. OCLC 17649090. OL 7387860M. Wikidata Q105670571. Planetary Surface Processes, Cambridge University Press, 2011, (ISBN 0-52-151418-5)

References

External links Homepage of H. Jay Melosh Archived December 17, 2013, at the Wayback Machine

Illustrations

Worked examples

Example 1 — a first encounter with H. Jay Melosh

Start with the simplest possible case. Write down what H. Jay Melosh 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 H. Jay Melosh 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 H. Jay Melosh 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 H. Jay Melosh

In research: H. Jay Melosh 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 H. Jay Melosh 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: H. Jay Melosh is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1947 births, 2020 deaths, American Astronomical Society, so understanding it makes those chapters shorter.
In everyday life: Look for H. Jay Melosh 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 H. Jay Melosh in 20 minutes

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

Frequently asked questions

What is H. Jay Melosh in simple terms?

H. Jay Melosh (June 23, 1947 – September 11, 2020) was an American geophysicist specialising in impact cratering.

Why does H. Jay Melosh 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 H. Jay Melosh?

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 H. Jay Melosh.