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
9 - Reaching for the stars
The emptiness of outer space
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
With this chapter, we let gravity lead us out of the familiar territory of the Solar System and into the arena of the stars. This is a tremendous leap: the furthest planet, Pluto, is never more than 50 AU away from the Earth, while the nearest stars to the Sun – the αCentauri system – are 270 000 AU away! In between is almost nothing. Yet, just as gravity determines the structure of the Sun, so also it governs the stars.
In this chapter: how astronomers measure the brightness and distances of stars.
Stars are the workplaces of the Universe. Stars made the rich variety of chemical elements of which we are made; they created the conditions from which our Solar System and life itself evolved; our local star – the Sun – sustains life and, as we shall see, will ultimately extinguish it from the Earth.
In this section: the huge number and variety of stars.
▷ The biggest stars are called giants, and the smallest are neutron stars.
Leaping out of the Solar System
The huge variety of kinds of stars gives a clue to why they can do so many different things. There are stars that are 20 times larger than the whole Solar System, and others that are smaller than New York City. Big stars can blow up in huge supernova explosions; small ones can convert mass into energy more efficiently than a nuclear reactor.
- Type
- Chapter
- Information
- Gravity from the Ground UpAn Introductory Guide to Gravity and General Relativity, pp. 103 - 108Publisher: Cambridge University PressPrint publication year: 2003