Book contents
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- Acknowledgments
- Prologue
- Chapter 1 A brief history
- Chapter 2 The universe
- Chapter 3 Stars
- Chapter 4 The solar nebula
- Chapter 5 Composition and chemical evolution of the solar nebula
- Chapter 6 The evidence from meteorites
- Chapter 7 Building planets
- Chapter 8 The giant planets
- Chapter 9 Satellites and rings
- Chapter 10 The refugees
- Chapter 11 The survivors: Mercury and Mars
- Chapter 12 The twins: Venus and the Earth
- Chapter 13 The Moon
- Chapter 14 The role of impacts
- Chapter 15 Epilogue: on the difficulty of making Earth-like planets
- Name index
- Subject index
Chapter 11 - The survivors: Mercury and Mars
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface to the First Edition
- Preface to the Second Edition
- Acknowledgments
- Prologue
- Chapter 1 A brief history
- Chapter 2 The universe
- Chapter 3 Stars
- Chapter 4 The solar nebula
- Chapter 5 Composition and chemical evolution of the solar nebula
- Chapter 6 The evidence from meteorites
- Chapter 7 Building planets
- Chapter 8 The giant planets
- Chapter 9 Satellites and rings
- Chapter 10 The refugees
- Chapter 11 The survivors: Mercury and Mars
- Chapter 12 The twins: Venus and the Earth
- Chapter 13 The Moon
- Chapter 14 The role of impacts
- Chapter 15 Epilogue: on the difficulty of making Earth-like planets
- Name index
- Subject index
Summary
The giant planets, their satellites, the asteroids and the comets formed very early. In the inner portions of the nebula, within a couple of AU of the Sun, a collection of dry rocky planetesimals that had survived the early solar winds, began slowly to assemble into larger bodies. Moonsized objects appeared. Finally several the size of Mercury and Mars dominated the scene but most were swept up by the two bodies that became Earthand Venus. A couple escaped into stable orbits and survive as Mercury and Mars.
Mercury
Although there is a common perception that Mercury is so close to the Sun that it is difficult to observe, it is often clearly visible away from city lights as a morning or evening star. Mercury is unique on account of its high density that tells us that it has a high content of metallic iron relative to rock. In contrast, the Moon has the reverse; a low content of metal relative to rock. Explanations for the peculiar nature of both bodies have a long history and much effort has been expended in attempts to fit one or both into overall schemes of planetary formation.
Like the Moon, the real significance of the anomalous nature of Mercury has only recently been appreciated; both these objects have played the role of red herrings in our attempts to understand the solar system [1].
- Type
- Chapter
- Information
- Solar System EvolutionA New Perspective, pp. 301 - 330Publisher: Cambridge University PressPrint publication year: 2001