Book contents
- Frontmatter
- Contents
- Preface
- 1 Why things move
- 2 From the falling apple to Apollo 11
- 3 How strong is gravity?
- 4 Fusion reactors in space
- 5 Living in curved spacetime
- 6 Ocean tides and gravity waves
- 7 The strange world of black holes
- 8 Cosmic energy machines
- 9 The big bang
- 10 The Universe: from simplicity to complexity
- 11 Gravity and the creation of matter
- 12 The many faces of gravity
- Index
9 - The big bang
Published online by Cambridge University Press: 05 August 2012
- Frontmatter
- Contents
- Preface
- 1 Why things move
- 2 From the falling apple to Apollo 11
- 3 How strong is gravity?
- 4 Fusion reactors in space
- 5 Living in curved spacetime
- 6 Ocean tides and gravity waves
- 7 The strange world of black holes
- 8 Cosmic energy machines
- 9 The big bang
- 10 The Universe: from simplicity to complexity
- 11 Gravity and the creation of matter
- 12 The many faces of gravity
- Index
Summary
THE STATIC UNIVERSE IN NEWTON'S THEORY
Back in the 1690s, Isaac Newton attempted an ambitious application of his law of gravitation. Newton wanted to describe, with the help of his theory of gravity, the largest physical system that can be imagined – the Universe. How did Newton fare in this attempt?
In a letter to Richard Bentley dated 10 December 1692, Newton expressed his difficulties in the following words:
It seems to me, that if the matter of our Sun and Planets and all ye matter in the Universe was evenly scattered throughout all the heavens, and every particle had an innate gravity towards all the rest and the whole space throughout which this matter was scattered was but finite: the matter on ye outside of this space would by its gravity tend towards all ye matter on the inside and by consequence fall down to ye middle of the whole space and there compose one great spherical mass. But if the matter was evenly diffused through an infinite space, it would never convene into one mass.
Figure 9–1, which illustrates a finite and uniform distribution of matter in the form of a sphere initially at rest, helps explain Newton's difficulty. Will the sphere stay at rest forever? The matter in the sphere has its own force of gravity, which tends to pull the different parts of the sphere toward one another, with the result that the sphere as a whole contracts. We have encountered this force of selfgravity in stars (Chapter 4) and in the phenomenon of black-hole formation (Chapter 7).
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- Chapter
- Information
- The Lighter Side of Gravity , pp. 157 - 176Publisher: Cambridge University PressPrint publication year: 1996