Einstein and the big bang

The Big Bang:

Fact or Fiction?

Einstein and the big bang

Cormac O’Raifeartaigh FRAS (WIT)

How big is the universe?

Is it finite or infinite?

Did it have a beginning?

Is it of finite age or eternal?

How old is the universe?

How will it end?

What is the nature of time?

What is the nature of space?

•

Gravity caused by mass of sun

Newton (1642-1727)

•

Infinite, eternal universe

Newton’s universe

•

Attractive force

Olber’s paradox

Seelinger’s paradox

The discovery of the galaxies (1925)

Starry nebulae at immense distance

Far beyond Milky Way

Edwin Hubble

Many galaxies

Motion of galaxies: redshift

frequency

of light depends on

motion of source relative to observer

measure motion of stars and galaxies

from light emitted

Doppler Effect

The runaway galaxies

Far-away galaxies rushing away

at a speed proportional to distance

v =

H

d

Galaxies moving away

(redshifts)

Linear relation between motion

and distance

Explanation for runaway galaxies?

•

Gravity pulls in not out

• Space is fixed

• Time has no beginning

Newton

How can galaxies be receding?

What is pushing out?

Modern theory of gravity

gravity = curvature of space-time

•

space + time not fixed

• spacetime

• affected by motion

• affected by mass

General

theory of relativity (Einstein, 1915)

Evidence for general relativity

•

Bending of light by gravity (1919)

•

Black holes

•

Time stretching by gravity

Apply relativity to the universe

Predicts

dynamic

Universe

Space expanding, contracting

3 possibilities (Friedman 1922, 24

)

Depends how much matter

Rejected by Einstein

Static

universe (1917)

G

+ λg

=

T

Lemaître’s universe (1927)

Redshifts of galaxies = expansion of space

?

Early data from Hubble

Eternal, expanding universe

Starts from Einstein universe at t = -

∞

Rejected by Einstein

Votre physique est abominable”

Ditto for Friedman models

Fr Georges Lemaître

Hubble’s law and relativity (1929)

Cosmic expansion?



RAS meeting (1930)

If redshifts are velocities and effect is non-local



Hubble’s law = expansion of space?

Static models don’t fit data

Dynamic relativistic models required



Friedman-Lemaître models

Time-varying radius

Density of matter decreases

The expanding, evolving universe (1930 -)

If redshifts represent expansion… Evolving universe

•

Eddington (1930, 31)

•

de Sitter (1930, 31)

Further remarks on the expanding universe Expanding universes of every flavour

•

Tolman (1930, 31)

Expansion caused by annihilation of matter ?

•

Einstein (1931, 32)

An origin for the universe?

Expanding

U

smaller in the past

Rewind Hubble graph to ‘origin’

Extremely dense, extremely hot

Explosive beginning at

R

= 0?

Fr Georges Lemaitre

The ‘big bang’ model (1931)

U

originally concentrated in

tiny volume

Extremely dense, hot

Expanding and cooling since

Wrong age (Hubble)

Singularity problem

Steady-state universe (1950s)

Alternative to big bang

(Fred Hoyle)

Expanding universe

BUT

Continuous creation of matter?

Unchanging universe

No beginning

No age problem

Radio-astronomy (1960s)

Bitter debate between S-S and BB

Study most distant galaxies

Compare with local galaxies

Density the same at all times? (S-S)

Or different? (BB)

Answer: different

Bonus: cosmic background radiation

Universal signal (1965)

Low frequency (microwave)

Low temperature (3K)

Echo of

Big Bang!

CMB discovered accidentally

Cosmology today

• Measurements by satellite

• Full spectrum of CMB

• Comparison with theory

COBE satellite (1992)

• Ground telescopes

• Balloon experiments

• Satellite experiments

New! Einstein’s steady-state model (WIT)

Unpublished AE manuscript

AE Archive (1931)

Contains ‘steady-state’ model of the cosmos

Expanding universe of constant matter density Continuous formation of matter from vacuum

Inconsistent theory

Fatal flaw Abandoned

Turns to evolving models

Einstein’s steady-state model (1930s-)

Hubble’s law (1929)

Expanding universe

Age problem of evolving models

Conflict with stellar ages

Unchanging universe?

Continuous creation of matter Associated with λ - energy of space

Anticipates Hoyle et al.

Doesn’t work: no creation term Einstein declines to alter GR!

Einstein’s steady-state model: key quotes

New solution

“In what follows, I wish to draw attention to a solution to equation (1) that can account for Hubbel’s facts, and in which the density is constant over time”

Matter creation

“If one considers a physically bounded volume, particles of matter will be

continually leaving it. For the density to remain constant, new particles of matter must be continually formed within that volume from space “

Dark energy

“The conservation law is preserved in that, by setting the λ-term, space itself is not empty of energy; its validity is well known to be guaranteed by equations (1).”

An abandoned model

A fatal flaw

Matter creation associated with λ

Null result masked by error

Derivation incorrect

Einstein’s crossroads

Identifed problem on revision Declined to amend GFE

Evolving models?

Significance of Einstein’s steady-state model

Unsuccessful theories important

Understanding the development of successful theories

New perspective on steady-state theory

Logical possibility: not a crank theory

Insight into Einstein’s philosophy

Discards model rather than add new term to GFE Occam’s razor approach

Insight into scientific progress

Slow dawning

Links with modern cosmology

Dark energy: creation energy and λ Cosmic inflation: de Sitter metric

Einstein’s steady-state model and cosmology today

Dark energy (1998)

Accelerated expansion (observation) Positive cosmological constant

Einstein’s dark energy

“The conservation law is preserved in that, by setting the λ-term, space itself is not empty of energy; its validity is well known to be guaranteed by equations (1).”

Cosmic inflation

Inflationary models use de Sitter metric

Used in all steady-state models

Flat curvature, constant rate of matter creation Different time-frame!

COBE measurements of CMB

• Expected temperature

• Expected frequency

• Perfect blackbody spectrum

COBE (1992)

Nobel Prize 2006

•

Radiation very uniform

•

Galaxy formation?

Problems

Horizon problem

why so uniform?

Galaxy problem

how did galaxies form?

Flatness problem

fine balance?

Background radiation raised new questions

Singularity problem

∞ density, ∞ curvature

at

t

= 0 ?

quantum gravity?

Einstein’s 1931 model (

F-E

)

Instability of static universe

Hubble’s observations

Expanding cosmos

Remove cosmic constant?

Adopt Friedmann 1922 analysis

Age and singularity problems

Einstein’s 1931 model (F-E)

Numerical estimates of radius and density

P ~ 108 _{light-years, ρ} ~ ₁₀-26 _g/cm3

Calculations problematic

H₀ ~500 kms-1_Mpc-1 _{: D}2 ~₁₀-55 _cm-2

Age estimate problematic

Not a periodic solution

Einstein-deSitter model (1932)

Remove curvature

Adopt Friedmann analysis

Calculate critical density

10-28 _g/cm3 _{: agrees with astrophysics}

Well-known model

Models: observational parameters needed

Spatial curvature

Cosmic constant

Deacceleration

Density of matter

Timespan

Hubble constant

=

_?

What do redshifts represent?

Is expansion a local effect

?

The formation of galaxies

Growth in static medium

Exponential growth by gravitational collapse

λ_j =c_s/(Gρ₀/π)1/2

Growth in expanding medium

Linear growth of density perturbations δρ/ρ ∝ R

Structure not from density fluctuations?

An origin for the universe?

Rewind Hubble graph

Extremely dense, extremely hot

Primeval atom

Expanding and cooling since

Singularity problem

∞ density, ∞ temp at t = 0 ? Quantum theory

Age problem

U

Lemaître’s hesitating universe (1931-34)

Primeval atom

Explosive expansion from radioactive decay

Expansion slows down

Positive cosmic constant

Energy of vacuum; stagnation

Indefinite timespan

Formation of structure?

Accelerated expansion

Cosmic rays = radiation from early universe?

Finale: Paradigm shift or slow dawning?

Hubble/Slipher

Empirical law for nebulae

Friedmann

Time-varying solutions

Lemaître

Theory and observation

Slow emergence of theory and evidence

Slow acceptance: no upsurge of interest 1935-65

Obs: Parsons, Huggins, Leavitt, Shapley

Models I: Einstein, de Sitter, Weyl, Lanczos, Robertson

Act IV Slow acceptance: 1935-65

Hot big bang

(1940s)

Nucleosynthesis in the hot infant universe? Background radiation from early universe?

Little interest from community

No search for the cosmic radiation General relativity difficult, abstruse

Steady-state universe

(1948)

Later ruled out by experiment

(1960s)

Radio-galaxy counts, CMB

Gamow, Alpher and Hermann

Act V Cosmic background radiation

Search for radio signals

Large, sensitive receiver

Universal signal (1965)

From every direction

Low frequency (microwave)

Low temperature (3K)

Echo of big bang

Radiation from early universe

Penzias and Wilson

Cosmology today

•

Satellite measurements of CMB

No interference from atmosphere

•

Expected temperature

•

Full spectrum

•

Perturbations

Planck Satellite (ESA): Results

Paradigm shift or slow dawning?

Revolutionary v normal science

The paradigm shift

Change of worldview occurs Social factors important

Incommensurability

Thomas Kuhn

Slow exploration of theory and observation

Slow acceptance of new paradigm (1935-65)

Exp U:

Tolman’s annihilation of matter

Non-static line element (1930)

Einstein, de Sitter models ruled out

Cause of cosmic expansion?

General evolutionary process

Transformation of matter into radiation

Rate of transformation

From Hubble’s law and from stellar physics

Influenced Einstein

Steady-state model

New results: Planck Satellite (ESA, 2013)

1.

Improved sensitivity

10

1

x



2.

Full spectrum of

T

anisotropy

3.

Gravitational lensing

4.

Polarization measurements

Planck results (2013)

1.

2.

Curvature: flat

Ω

= -0.0005 +- .07

3. Positive cosmic constant

Ω

= 68%

4. New mass/energy parameters

67.3 +- 1.2 km/s/MPC

Age = 13.8 billion yr

Planck Results

1.

Power spectrum

Not scale invariant n

= 0.96

2.

Compatible with inflation

3.

Complex inflation out

Hybrid models out Cyclic models out

The big bang model - questions

Nature of dark energy?

Nature of dark matter?

Particle experiments?

Which model of inflation?

The multiverse?

The singularity problem

What does time zero mean?

No-boundary universe