Albert Einstein and the
Dark Side of the Universe

Professor Howard Baer

High Energy Physics (theory)

Florida State University

Einstein:Time Magazine Person of the Century

At end of century, Albert Einstein named ``Person of the Century'' by Time Magazine

Why?

Isaac Newton: 1643-1727

3 laws of motion: F=ma

Law of universal gravitation

Can predict path of motion of planets, baseballs,... as function of time

Time is universal

JC Maxwell: 1831-1879

Unified treatment of electricity and magnetism

Light as an electromagnetic wave

Embodied by four ``Maxwell eq'ns''

Albert Einstein: 1879-1955

As youth, fascinated by behavior of magnets

Excel: math/physics

Anti-authoritarian

``Won't amount to much!''

Clerk in Swiss patent office

1905: the ``miracle year''

Photoelectric effect: photons

Brownian motion: molecular size

Special Relativity space+time= spacetime

Special Relativity E=mc^2

Special Relativity

Laws of physics same for all inertial observers

Speed of light =300,000,000 m/s for all observers

Unify space and time

Unify mechanics and electrodynamics

Time dilation/ length contraction

Verified daily in physics: e.g. muon decay

SR inconsistent with Newton's gravity: no action at a distance

1908: still in patent office in Bern: happiest thought of his life:

A freely falling person will not notice their own weight

Principle of Equivalence: in FF reference frame, the laws of physics are those of SR

Gravitational redshift

Bending of light rays by the sun

Einstein: 1909-1914

1909: Assoc. Professor at Zurich

1911: Full Professor at Prague

1913: Collaboration begins with mathematician Marcel Grossmann

Learns tensor calculus and non-Riemannian geometry, which is exactly suited for the General Relativity theory (GR)

1914: Kaiser Wilhelm Inst. in Berlin

General Theory of Relativity

Formulates theory in curved spacetime

Curvature -> gravitational pull

November 1915 breakthrough

Einstein equations relate curvature of spacetime to matter/energy content

Matter tells spacetime how to curve

Curvature tells matter how to move

Predict gravity waves/ orbit of Mercury

Consequences of GR theory

Consistent EM, mechanics and gravity

Gravitational waves: how a moving matter distribution tells spacetime how to curve

Detected indirectly via spin rate of neutron stars

Frame dragging with Gravity Probe B!

Direct detection with LIGO detectors in Hanford, WA and Lousiana?

Stars

White dwarves: collapsed star size ~earth; mass of sun

Neutron stars:

Black holes: total gravitational collapse so even light can't escape the gravitational pull

Cosmology: the universe as a whole

GR predicts universe to be expanding or contracting

Einstein's CC

1929: Hubble finds universe is expanding

Abandon CC

Big Bang theory

Universe composed of galaxies

All rushing apart

Universe began with a hot ``Big Bang''

t(universe)~13.7 billion years old

t(earth)~4.2 billion years

Big Bang theory 2

All galaxies rushing apart

Can predict abundance of cosmic elements: nucleosynthesis

Agrees with observation: t~ 1sec ABB

Relic radiation from Big Bang

BB theory: early universe very hot

Relic radiation from Big Bang should pervade all space

Detected 1965: Penzias and Wilson

1990-2003: COBE/WMAP

Precision cosmology

Recent precision determination of composition of universe:

5% atoms: what we/planets/stars made of

25% dark (non-shining) particles

70% dark energy (?)

What is dark matter? Dark energy?

Einstein Cosmo. Constant =dark energy?

The dark side of the Universe

Dark matter properties:

Massive stable particle with no electric charge: not present in the laws of physics as we know them!

Hunt for dark matter

Large hadron collider at CERN (Swiss/French border)

startup: 2008

proton-proton collisions at 14 trillion electron volts!

Search for dark matter relics from the Big Bang

Ultrasensitive, ultracold detectors deep undergound search for rare nuclear scattering from dark matter particles: e.g. CDMS in Sudan mine, Minnesota

Dark matter in core of Sun

DM collects in core of Sun

Annihilates into neutrinos

Neutrinos detected by muon tracks in ice at south pole!

The hunt is on to identify the ``Dark Side of the Universe''!

Dark matter production at accelerators

Search for DM relics from Big Bang

DM annihilation in core of Sun

DM annihilation to anti-matter in galactic halo

Dark energy: telescopic observations of most distant objects in the Universe: Einstein's cosmological constant or ????

Howard Baer

2005-04-06T17:04:36