physics

Reinventing Gravity

Reinventing Gravity is a physics 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 Reinventing Gravity rather than just read about it. In short: Reinventing Gravity: A Scientist Goes Beyond Einstein is a science text by John W. Moffat, which explains his controversial theory of gravity.

Key takeaways

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

Reference excerpt

Reinventing Gravity: A Scientist Goes Beyond Einstein is a science text by John W. Moffat, which explains his controversial theory of gravity.

Moffat's theory

Moffat's work culminates in his nonsymmetric gravitational theory and scalar–tensor–vector gravity (now called MOG). His theory explains galactic rotation curves without invoking dark matter. He proposes a variable speed of light approach to cosmological problems, which posits that G/c is constant through time, but G and c separately have not been. Moreover, the speed of light c may have been much higher (at least trillion trillion times faster than the normal speed of light) during early moments of the Big Bang. His recent work on inhomogeneous cosmological models purports to explain certain anomalous effects in the CMB data, and to account for the recently discovered acceleration of the expansion of the universe. The theory is based on an action principle and postulates the existence of a vector field, while elevating the three constants of the theory to scalar fields. In the weak-field approximation, STVG produces a Yukawa-like modification of the gravitational force due to a point source. Intuitively, this result can be described as follows: far from a source gravity is stronger than the Newtonian prediction, but at shorter distances, it is counteracted by a repulsive fifth force due to the vector field.

Reception The book was positively reviewed in EE Times, Physics World and Publishers Weekly.

See also Einstein Wrote Back, another book by Moffat

References

Worked examples

Example 1 — a first encounter with Reinventing Gravity

Start with the simplest possible case. Write down what Reinventing Gravity claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In physics, 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 Reinventing Gravity 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 Reinventing Gravity 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 Reinventing Gravity

In research: Reinventing Gravity appears in physics 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 Reinventing Gravity 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: Reinventing Gravity is common in secondary-school and first-year university syllabi. It links to neighbouring topics 2008 non-fiction books, Books by John Moffat (physicist), Physics book stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Reinventing Gravity 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 Reinventing Gravity in 20 minutes

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

Frequently asked questions

What is Reinventing Gravity in simple terms?

Reinventing Gravity: A Scientist Goes Beyond Einstein is a science text by John W. Moffat, which explains his controversial theory of gravity.

Why does Reinventing Gravity matter?

Because it connects several physics 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 Reinventing Gravity?

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 Reinventing Gravity.