Log In
Or create an account ->
Imperial Library
Home
About
News
Upload
Forum
Help
Login/SignUp
Index
Cover
Half Title
Title Page
Copyright
Dedication
Contents
Preface
Background: what you need to know before you start
1. Gravity on Earth: the inescapable force
Galileo: the beginnings of the science of gravity
The acceleration of gravity is uniform
Trajectories of cannonballs
Galileo: the first relativist
2. And then came Newton: gravity takes center stage
The second law: weight and mass
The third law, and its loophole
Preview: Newton’s gravity
Action at a distance
The new equivalence principle
The gravitational redshift of light
Gravity slows time
Summing up
3. Satellites: what goes up doesn’t always come down
Taking motion apart
Acceleration, and how to change your weight
Getting into orbit
4. The Solar System: a triumph for Newtonian gravity
How to invent Newton’s law for the acceleration of gravity
The orbits of the planets described by Newton’s law of gravity
What is the value of G?
Kepler’s laws
The Sun has a little orbit of its own
Geostationary satellites
The gravitational attraction of spherical objects
Playing with the orbit program
Black holes before 1800
Light is deflected by the Sun’s gravity
5. Tides and tidal forces: the real signature of gravity
Tidal forces in free fall
Ocean tides
Tides from the Sun
Spring and neap tides
What the tidal forces do to the oceans, the Earth, and the Moon
Tides elsewhere in astronomy
Jupiter gives Mercury’s story another twist
Triumph of Newtonian gravity: the prediction of Neptune
Tiny flaw of Newtonian gravity: Mercury’s perihelion motion
6. Interplanetary travel: the cosmic roller-coaster
Getting away from the Earth
Plain old momentum, and how rockets use it
Energy, and how planets never lose it
Getting to another planet
The principle of the slingshot
Using Jupiter to reach the outer planets
Slinging towards the Sun
Force and energy: how to change the energy of a body
Time and energy
7. Atmospheres: keeping planets covered
In the beginning . . .
. . . was the greenhouse . . .
. . . and then came Darwin
The ones that get away
The Earth’s atmosphere
Pressure beats gravity: Archimedes buoys up balloons
Pressure beats gravity again: Bernoulli lifts airplanes
Helium balloons and the equivalence principle
Absolute zero: the coldest temperature of all
Why there is a coldest temperature: the random nature of heat
The ideal gas
An atmosphere at constant temperature
The Earth’s atmosphere
The atmospheres of other planets
Quantum theory and absolute zero
8. Gravity in the Sun: keeping the heat on
Sunburn shows that light comes in packets, called photons
A gas made of photons
Einstein in 1905
Gravity keeps the Sun round
The Sun is one big atmosphere
The Standard Model of the Sun
The structure of the Sun
How photons randomly ‘walk’ through the Sun
Rotation keeps the Sun going around
Solar seismology: the ringing Sun
9. Reaching for the stars: the emptiness of outer space
Leaping out of the Solar System
How far away are the stars?
How bright are stars?
Astronomers’ units for brightness
Standard candles: using brightness to measure distance
10. The colors of stars: why they are black (bodies)
The colors of stars
Why stars are black bodies
The color of a black body
Relation between color and temperature: greenhouses again
Spectral lines: the fingerprint of a star
How big stars are: color and distance tell us the size
But why are stars as hot as they are, and no hotter?
Looking ahead
11. Stars at work: factories for the Universe
Star light, star bright . . .
. . . first star I see tonight
Cooking up the elements
The solar neutrino problem
Life came from the stars, but would you have bet on it?
12. Birth to death: the life cycle of the stars
Starbirth
The gravitational thermostat
The main sequence
Giants
Degenerate stars: what happens when the nuclear fire goes out
The Chandrasekhar mass: white dwarfs can’t get too heavy
Neutron stars
Fire or ice: supernova or white dwarf
Death by disintegration
What is left behind: cinders and seeds
13. Binary stars: tidal forces on a huge scale
Looking at binaries
The orbit of a binary
Planetary perturbations
Tidal forces in binary systems
Accretion disks in binaries
Compact-object binaries
Fun with the three-body problem
14. Galaxies: atoms in the Universe
Globular clusters: minigalaxies within galaxies
Describing galaxies
Galaxies are speeding apart
Measuring the Universe: the distances between galaxies
Most of the Universe is missing!
Gangs of galaxies
The missing mass
Radio galaxies: the monster is a giant black hole
Quasars: feeding the monster
Galaxy formation: how did it all start? Did it all start?
15. Physics at speed: Einstein stands on Galileo’s shoulders
Fast motion means relativity
Relativity is special
The Michelson-Morley experiment: light presents a puzzle
Michelson’s interferometer: the relativity instrument
Special relativity: general consequences
The extra inertia of pressure
Conclusions
16. Relating to Einstein: logic and experiment in relativity
Nothing can travel faster than light
Light cannot be made to stand still
Clocks run slower when they move
The length of an object contracts along its motion
Loss of simultaneity
The mass of an object increases with its speed
Energy is equivalent to mass
Photons have zero rest-mass
Consistency of relativity: the twin paradox saves the world
Relativity and the real world
17. Spacetime geometry: finding out what is not relative
Gravity in general relativity is . . .
. . . geometry
Spacetime: time and space are inseparable
Relativity of time in the spacetime diagram
Time dethroned . . .
. . . and the metric reigns supreme!
The geometry of relativity
Proper measures of time and distance
Equivalence principle: the road to curvature . . .
. . . is a geodesic
The equivalence principle: spacetime is smooth
18. Einstein’s gravity: Einstein climbs onto Newton’s shoulders
Driving from Atlanta to Alaska, or from Cape Town to Cairo
Dimpled and wiggly: describing any surface
Newtonian gravity as the curvature of time
Do the planets follow the geodesics of this time-curvature?
How to define the conserved energy of a particle
The deflection of light: space has to be curved, too
Space curvature is a critical test of general relativity
How Einstein knew he was right: Mercury’s orbital precession
Weak gravity, strong gravity
19. Einstein’s recipe: fashioning the geometry of gravity
Einstein’s kitchen: the ingredients
Einstein’s kitchen: the active gravitational mass comes first
Einstein’s kitchen: the recipe for curving time
Einstein’s kitchen: the recipe for curving space
Einstein’s kitchen: the recipe for gravitomagnetism
The geometry of gravitomagnetism
Gyroscopes, Lense, Thirring, and Mach
The cosmological constant: making use of negative pressure
The big picture: all the field equations
The search for simplicity
General relativity
Looking ahead
20. Neutron stars: laboratories of strong gravity
Nuclear pudding: the density of a neutron star
It takes a whole star to do the work of 100 neutrons
What would a neutron star look like?
Where should astronomers look for neutron stars?
Pulsars: neutron stars that advertise themselves
The mystery of the way pulsars emit radiation
The rotation rate of pulsars and how it changes
Puzzles about the rotation of pulsars
Pulsars in binary systems
X-ray binary neutron stars
Gamma-ray bursts: deaths of neutron stars?
The relativistic structure of a neutron star
The relation of mass to radius for neutron stars
Neutron stars as physics labs
21. Black holes: gravity’s one-way street
The first black hole
What black holes can do – to photons
The gravitational redshift
Danger: horizon!
Getting away from it all
Singularities, naked or otherwise
What black holes can do . . . to orbits
Making a black hole: the bigger, the easier
Inside the black hole
Disturbed black holes
Limits on the possible
The uniqueness of the black hole
Spinning black holes drag everything with them
The naked truth about fast black holes
Mining the energy reservoir of a spinning black hole
Accretion onto black holes
The signature of the supermassive black hole in MCG-6-30-15
Wormholes: space and time tubes
Hawking radiation: black holes are truly black bodies
Black hole entropy: a link to nineteenth century physics
Black hole entropy: a link to twenty-first century physics
22. Gravitational waves: gravity speaks
Gravitational waves are inevitable
Transverse waves of tidal acceleration
How gravitational waves act on matter
Early confusion: are gravitational waves real?
How gravitational waves are created
Strength of gravitational waves
Gravitational waves carry energy, lots of energy
The Binary Pulsar: a Nobel-Prize laboratory
Gravitational waves from binary systems
Listening to black holes
Gravitational collapse and pulsars
Gravitational waves from the Big Bang: the Big Prize
Catching the waves
Michelson returns: the relativity instrument searches for waves
LISA: catching gravitational waves in space
23. Gravitational lenses: bringing the Universe into focus
Pretty obvious, really, . . .
. . . but not always easy
How a gravitational lens works
Why images get brighter
Making multiple images: getting caustic about light
The Einstein ring
MACHOs grab the light
The third image: the ghost in a mirror
Lensing shows us the true size of quasars
Weak lensing reveals strong gravity
24. Cosmology: the study of everything
What is “everything”?
Copernican principle: “everything” is the same “everywhere”
The Hubble expansion and the Big Bang
The accelerating Universe
Was there a Big Bang?
Looking back nearly to the beginning
Cosmic microwave background: echo of the Big Bang
The rest frame of the Universe
Big Crunch or Big Freeze: what happens next?
Cosmology according to Newton
Cosmology according to Einstein
Evolving the Universe
The cosmological scale-factor
What is the cosmological expansion: does space itself expand?
The age of the Universe
25. The Big Bang: the seed from which we grew
Physical cosmology: everything but the first nanosecond
The expansion of the quark soup and its radiation
The laws of physics prefer matter over anti-matter
The Universe becomes ordinary
Making helium: first steps toward life
Does it correspond to reality?
Three and only three neutrinos: a triumph for Big Bang physics
From nuclei to atoms: the Universe goes transparent
The evolution of structure
Ghosts of the dark matter
What is the dark matter?
26. Einstein’s Universe: the geometry of cosmology
Cosmology could be complicated . . .
. . . but in fact it is simple (fortunately!)
Gravity is geometry: what is the geometry of the Universe?
Friedmann’s model universes
What the Universe looks like
27. Ask the Universe: cosmic questions at the frontiers of gravity
The puzzle of the slightly lumpy Universe
Einstein’s “big blunder”
The cosmological constant in particle physics
Inflation: a concept waiting for a theory
Inflation power: the active vacuum
Inflating the Universe
Inflation put to the test
Is inflation still going on?
Is Einstein’s law of gravity simply wrong?
Cosmic defects
Cosmic rays
Quantum gravity: the end of general relativity
A Universe for life: the Anthropic Principle
Causality in quantum gravity: we are all quantized
The quantization of time?
Time for the twenty-first century
Appendix
Glossary
Index
← Prev
Back
Next →
← Prev
Back
Next →