Book contents
- Frontmatter
- Contents
- Overview
- Prologue
- A note on scientific units
- Acknowledgements
- Part I Views of Venus, from the beginning to the present day
- Part II The motivation to continue the quest
- Chapter 9 Origin and evolution
- Chapter 10 Atmosphere and ocean
- Chapter 11 A volcanic world
- Chapter 12 The mysterious clouds
- Chapter 13 Superwinds and polar vortices
- Chapter 14 The climate on Venus, past, present and future
- Chapter 15 Could there be life on Venus?
- Part III Plans and visions for the future
- Epilogue
- References and acknowledgements
- Appendix A Chronology of space missions to Venus
- Appendix B Data about Venus
- Index
- Plate section
- References
Chapter 14 - The climate on Venus, past, present and future
from Part II - The motivation to continue the quest
Published online by Cambridge University Press: 05 September 2014
- Frontmatter
- Contents
- Overview
- Prologue
- A note on scientific units
- Acknowledgements
- Part I Views of Venus, from the beginning to the present day
- Part II The motivation to continue the quest
- Chapter 9 Origin and evolution
- Chapter 10 Atmosphere and ocean
- Chapter 11 A volcanic world
- Chapter 12 The mysterious clouds
- Chapter 13 Superwinds and polar vortices
- Chapter 14 The climate on Venus, past, present and future
- Chapter 15 Could there be life on Venus?
- Part III Plans and visions for the future
- Epilogue
- References and acknowledgements
- Appendix A Chronology of space missions to Venus
- Appendix B Data about Venus
- Index
- Plate section
- References
Summary
Let us begin with a thought experiment. Had Venus and Earth been swapped at birth – that is, at the time when they had accumulated virtually all of their present mass but before their atmospheres were fully evolved – what would the inner Solar System look like today? In this thought experiment, Venus is now at Earth’s distance from the Sun, and Earth 30 per cent closer than it was. Venus still rotates slowly and has any bulk compositional differences it acquired by forming at the closer position to the centre of the protosolar cloud, or as a result of any random processes that actually happened when planetesimals were combining to form the planets.
Currently, theories of the formation of the Solar System would have the gases in the protosolar cloud dissipate into space, and the atmospheres of Earth and Venus form later, mostly from gases that exhaled from their interiors. This would not have changed in their new positions, and in any case we believe at present that the gases that were supplied to the atmospheres of both planets were roughly the same. The motions of the planetesimals within the accretion zone jumbled the condensed and trapped volatiles that would later form the atmospheres of each planet. If Earth and Venus were truly identical in composition at the outset then presumably the result of swopping orbits over 4 billion years ago would be to produce much the same result as we have today.
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- The Scientific Exploration of Venus , pp. 215 - 224Publisher: Cambridge University PressPrint publication year: 2014