ECHOES OF THE BIG BANG

CAROLIN CRAWFORDGRESHAM PROFESSOR OF ASTRONOMY

NASA, ESA

Stephen Leshin

Stephen Leshin

Edwin Hubble

Stephen Leshin

UVX-rays micro-wave

radioIR

long wavelength

γ-rays

short wavelength

space-exploratorium.com

Georges Lemaitre

THE ‘PRIMEVAL ATOM’

THE ‘BIG BANG’

Fred Hoyle

COSMOLOGICAL PRINCIPLEThe Universe is isotropic and

homogeneous Georges Lemaitre Fred Hoyle

NASA/ESA/Illingworth et al

Maddox et al

SDSS / Blanton

NASA/ESA

1.8 billion years

NASA/NOAA/GSFC/Suomi NPP/VIIRS/Norman Kuring

1.8 billion years 3-4 billion years

NASA/ESA/Illingworth et al

COSMOLOGICAL PRINCIPLEThe Universe is isotropic and

homogeneous…in time as well as space

RADIO SOURCE NUMBER COUNTS

Steady State UniverseTime and place are unimportantThe distant Universe resembles the local

Big Bang UniverseTime is important; the Universe changes and

evolvesThe distant Universe is younger than the local

Observed distant radio sources as they were in the past

count numbers of radio sources at different brightnesses

Martin Ryle

ESO/M Kornmesser

George Gamow

THE ORIGIN OF THE CHEMICAL ELEMENTSNASA/ESA/Nota

NASA/ESA

THE HELIUM PROBLEM

THE DISCOVERY OF THE COSMIC MICROWAVE BACKGROUND

Arno Penzias & Robert Wilson

Wavelength (cm)

Inte

nsity

0.03 0.3 3 30 300

NASA

Wavelength (cm)

Inte

nsity

0.03 0.3 3 30 300

NASA

COBE 1989

FIRAS

NASA

Wavelength (cm)

Inte

nsity

0.03 0.3 3 30 300

NASA

FIRAS

NASA

ANISOTROPIESCOBE

DMR

NASA

TEMPERATURE VARIATIONS = DENSITY FLUCTUATIONS

COBE

• John Mather George Smoot

NASA

Fermilab

THE FLATNESS PROBLEM

THE HORIZON PROBLEM

Addison Wesley

THE HORIZON PROBLEM

Addison Wesley

Fermilab

Radiation-dominated era

CMBR

Fermilab

Radiation-dominated era

CMBRbaryon-radiation fluid

TEMPERATURE VARIATIONS = DENSITY FLUCTUATIONS NASA

ordinary matter pulls together under gravity

radiation pressure of photons pushes outwards

dark matter clusters under gravity

W Hu

the ordinary (baryonic) matter bounces to create oscillations in the density

TEMPERATURE VARIATIONS = DENSITY FLUCTUATIONS NASA

WMAP Hinshaw et al

THE POWER SPECTRUM

BOOMERanG experiment

BOOMERanG experiment

BOOMERanG experiment

WMAP 2001

NASA

COBEWMAP

NASA

WMAP Hinshaw et al

Total matter content (curvature of space)

Ordinary matter

Dark + ordinary matter

Dark energy

Ωtotal

Ωbaryons

ΩΛ

Ωmass

Hu & Dodelson

ESO

WMAP

4.6 % ordinary matter24 % dark matter71.4 % dark energy

age of Universe 13.772±0.059 billion years

V

NASA/JPL-Caltech/ESA

ESA / Planck collaboration

WMAP PLANCK

ESA / Planck collaboration

WMAP

4.6 % ordinary matter24 % dark matter71.4 % dark energy

age of Universe 13.772±0.059 billion years

PLANCK

4.9 % ordinary matter26.8 % dark matter69 % dark energy

NASA / WMAP Science team

HOW THE EARTH MOVESWED 3RD APRIL 1PM