Book contents
- Frontmatter
- Contents
- Preface
- Background: what you need to know before you start
- 1 Gravity on Earth:
- 2 And then came Newton
- 3 Satellites
- 4 The Solar System
- 5 Tides and tidal forces
- 6 Interplanetary travel
- 7 Atmospheres
- 8 Gravity in the Sun
- 9 Reaching for the stars
- 10 The colors of stars
- 11 Stars at work
- 12 Birth to death
- 13 Binary stars
- 14 Galaxies
- 15 Physics at speed
- 16 Relating to Einstein
- 17 Spacetime geometry
- 18 Einstein's gravity
- 19 Einstein's recipe
- 20 Neutron stars
- 21 Black holes
- 22 Gravitational waves
- 23 Gravitational lenses
- 24 Cosmology
- 25 The Big Bang
- 26 Einstein's Universe
- 27 Ask the Universe
- Appendix: values of useful constants
- Glossary
- Index
24 - Cosmology
The study of everything
Published online by Cambridge University Press: 05 June 2012
- Frontmatter
- Contents
- Preface
- Background: what you need to know before you start
- 1 Gravity on Earth:
- 2 And then came Newton
- 3 Satellites
- 4 The Solar System
- 5 Tides and tidal forces
- 6 Interplanetary travel
- 7 Atmospheres
- 8 Gravity in the Sun
- 9 Reaching for the stars
- 10 The colors of stars
- 11 Stars at work
- 12 Birth to death
- 13 Binary stars
- 14 Galaxies
- 15 Physics at speed
- 16 Relating to Einstein
- 17 Spacetime geometry
- 18 Einstein's gravity
- 19 Einstein's recipe
- 20 Neutron stars
- 21 Black holes
- 22 Gravitational waves
- 23 Gravitational lenses
- 24 Cosmology
- 25 The Big Bang
- 26 Einstein's Universe
- 27 Ask the Universe
- Appendix: values of useful constants
- Glossary
- Index
Summary
Cosmology is the study of the Universe as a whole. A century ago, scientists had only a vague idea about what even the Milky Way galaxy was like, and they were only able to make guesses about the Universe beyond. Most educated people believed that the nature and history of the Universe were simply matters for religious belief. The word “cosmology” referred to the set of beliefs one had about the whole world: Earth, God, Universe, Creation.
In this chapter: we introduce our study of cosmology. We focus on the measurements that astronomers can make about the Universe as a whole: the Hubble expansion and the acceleration of the Universe. We learn about homogeneity and the Copernican principle, about what the expansion does to space and what is in it, and how to compute the evolution of the Universe.
▷ The image under the text on this page reminds us that creation myths and cosmologies were central parts of the belief systems of ancient peoples. It is remarkable how many cultures believed in a beginning of time, a moment of creation. The ancient Egyptians had several creation myths. The Hebrew creation story even orders the events in much the same way that modern science would, although on a vastly different time-scale. More than any other branch of physics, the scientific study of cosmology raises religious sensitivities and addresses questions that have long been regarded the domain of philosophy and belief.
- Type
- Chapter
- Information
- Gravity from the Ground UpAn Introductory Guide to Gravity and General Relativity, pp. 345 - 366Publisher: Cambridge University PressPrint publication year: 2003