The Universe

Piet Mulders

mulders@few.vu.nl

http://www.nat.vu.nl/~mulders

September 4, 2009

The universe

• Introduction• Basic concepts• Structure of Matter• The fundamental forces• Symmetry• The history of the universe• Open questions … and where to find the

answers

Introduction

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Big Bang – History of Universe

• Our vision of ultimate evolution based on (known!) concepts

• (Amazingly) good agreement!• Cosmic Microwave Background (CMB) as proof

Physics2006

• John C. Mather (1946)NASA Goddard Space Flight Center, Greenbelt, MD, USA(PhD from Berkeley)

• George F. Smoot (1945)University of California, Berkeley, CA, USA(PhD from MIT)

for …

For their discovery of the blackbody form and anisotropy of the cosmic microwave background radiation

From www.nobel.se:The Nobel Prize in Physics 2006 has been awarded to U.S. physicists John Mather (NASA) and George Smoot (LBL) for their discovery of the basic form of the cosmic microwave background radiation as well as its small variations in different directions. The very detailed observations that the laureates have carried out from the COBE satellite have played a major role in the development of modern cosmology into a precise science.

Measuring temperatures in the universe

max

1~T

Looking at the color (maximum of light emission) or more general to the form of the emission spectrum

4~Energy T

These emission shapes can also be created in a lab and were first described by Max Planck (Nobel prize 1918)

History of the CMB

• Expanding universe (Friedmann 1922, Lemaitre 1927, Willem de Sitter) and redshift (Edwin Hubble 1929)

• Richard Tolman (working with Hubble) showed in 1934 that cooling blackbody radiation in an expanding universe retains its form

• Prediction of Cosmic Background Radiation (George Gamov 1948; Ralph Alpher and Robert Herman 1950)

• Accidental observation of Cosmic Microwave Background (CMB) at Bell Labs by Arno Penzias & Robert Wilson 1965 (Nobel prize 1978)

• Robert Dicke, Peebles, Roll and Dave Wilkinson 1965 realized immediately that CMB had been found!

Origin of the CMB

BIG BANG

13.7 billion years ago

Big Bang – History of Universe

• Our vision of ultimate evolution based on (known!) concepts

• (Amazingly) good agreement!• Cosmic Microwave Background (CMB) as proof

• Theory/understanding of space-time• Underlying symmetries• Consistent set of forces

Basic concepts

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Space-time

• We live in a 3+1 dimensional space (possibly embedded in a higher-dimensional space in which a number of dimensions are ‘compactified’ and/or are only relevant at extreme scales)

• Basic symmetry: invariance under Poincaré transformations

• ConceptsEnergy, momentum, angular momentum

• Notion of degrees of freedomposition, time, particles/waves, observables, …

Poincaré symmetry

• Physical laws are invariant under– Translations in space ant time– Rotations– Boosts (change to a reference frame moving with a

constant velocity)

• Forces break the ‘constant velocity’ and equations of motion describe what is happening with particular degrees of freedom (F = m a)

• Symmetries imply certain quantities to be conserved:– Time translations: conservation of energy– Space translations: conservation of momentum– Rotations: conservation of angular momentum

The (theoretical) framework

c

Action: E t ~ p r ~ ℓ

velo

city

: v

=

p

c2/E

0ђ

Quantum mechanics

Relativisticquantum mechanics

Classical mechanics

Special relativity

light

small heavy

big

INLEIDING

299792458 /c m s

341.055 10 Js

The structure of matter

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MaterieMATTER

MaterieMATTER

ELECTRONATOM10-10 m

The periodic table

MaterieMATTER

ELECTRONATOM10-10 m

MATTER

ELECTRONATOM10-10 m

NUCLEUS10-14 m

NEUTRINO

ATOM10-10 m

ELECTRON

MATTER

NUCLEUS10-14 m

NEUTRINO

NUCLEONproton/neutron10-15 m

Atomic nuclei

Island of stability

Atomic nuclei

• Isotopes• Radioactivity

alphabeta gamma

after 15 min.

more on neutrinos

Neutrino’s

Building blocks of the subatomic world

Materie

ELECTRON

MATTER

ATOM10-10 m

NUCLEUS10-14 m

NEUTRINO

NUCLEONproton/neutron10-15 m

ELECTRON

MATTER

ATOM10-10 m

NUCLEUS10-14 m

NEUTRINO

NUCLEONproton/neutron10-15 m

QUARKup/down

Basic building blocks of matter

home

Really down to bits!

1079 electrons in the Universe

How do we know this?

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By using the largest microscopes on Earth

Antiparticles

Standard model content

• 3 particle families

The fundamental forces

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Forces in daily life

Electromagnetism Gravity

• Two of four basic forces• Both based on fundamental principles

Standard model

• 3 particle families• 4 fundamental forces

• strong force quark nucleon atomic nucleus• electromagnetic force atom molecule complexity• weak force decay

• gravity

UNIFICATION

more on gravity

Standard model

• 3 particle families• 4 fundamental forces• Corresponding force

particles And a consistent theoretical framework: a renormalizable non-abelian gauge theory

Steven WeinbergSheldon GlashowAbdus Salam

Gerard ‘t HooftMartinus Veltman

Example: neutron decay

Neutron beta-decay

At the quark level

n p + e + e

d u + e + e

How do quarks and gluons give the proton its properties?

A one-line theory: QCDMassless quarks

and gluons

Protons and neutrons:Basic constituents of atomic nuclei forming99.5 % of the visible mass in the universe

Mass of nucleon

• Almost massless quarks: mu ~ 5 MeV and md ~ 10 MeV

• constant force T0 = 1 GeV/fm leads to confinement of color over distances of ~ 0.8 fmPressure in bubble: B ~ 100 MeV/fm3 EV = 4BR3/3 ~ 200 MeV

• Momentum p ~ 1/R ~ 250 MeV

• Energy per quark: EQ ~ 250 MeV

• Total energy: E ~ 940 MeV = mass of nucleon

d uu

u d d

proton

neutron

Central theme of standard

model:SYMMETRY

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Mirror symmetry

• Mirror world?• Example: top• Mirror world exist• Conclusion: mirror symmetry is a

symmetry of our daily world

Broken mirror symmetry

• A pion decays into spinning particles

• For a neutrino only one spin direction exist!

• But how can we measure this?

• spin + charge magnet

• Only observed at N-pole of the magnet!

lefthanded

For neutrinos there exist L but not R

mirror imagesrighthanded

CP symmetry

• Mirror symmetry (P) is broken in the subatomic world• Particle-antiparticle symmetry (C) is also broken• But … the combination is indeed a symmetryalmost

__ _K0 = ds, K0 = sd have slightly different masses and decay in a different way

CPT symmetry

Time reversal

• CPT is (to our present knowledge!) indeed a good symmetry of the world

• CP is almost a good symmetry• Thus also time reversal is almost a good

symmetry, but not exact!• This symmetry breaking allows for the surplus of

matter over antimatter in the universe (even if this is only 1 : 109)Number of baryons 0,25 x 1079 (~ 0,25 per m3)But the number of photons and neutrinos 1088 (~ 400 per cm3)

more on mass in universe

CP-violation in standard model

CP-violation can be implemented in the standard model through complex phase(s) in CKM-matrix.This requires at least three families!

CabibboKobayashiMaskawa

The history of the universe

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BIG BANG

13.7 billion years ago

inflation

and finally now….

Open questions in the standard model

• 3 particle families• 4 fundamental forces• corresponding force particles• Glimp of the ‘Higgs particle(s)’?

… and very many questions remaining!

(Anti)matter in universe ??Black holes ?

Space and time ?Points ?Strings ?

Chaos ?

Phase tr

ansitions ?

Gravitational

waves Why 3 families ??

Neutrinos ?

Their masses ?

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Where to find the answers?

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In accelerators ?

• Collissions in the Large Hadron Collider at CERN– New particles

(Higgs, …)– New symmetries

(Fermion-Boson symmetry)

– Origin of mass – Origin of symmetry

breaking (e.g. CP-violation)

ATLAS

CMS

LHCb

(future) detectors at CERN

Super KamiokandeUnderground ?

Underground ?

• Atmospheric neutrinos oscillate over thousands of kilometers

• Solar neutrinos change flavor in the Sun

• Masses m ~ 0.01 eV

(that is extremely small, but compare k ~ 104 eV/K) Sudbury Neutrino Observatory (SNO)

In the mediterranean?or the ice?

• Looking for high energy cosmic neutrinos– Supernovae– Neutron stars– Black holes ANTARE

S

KM3NET

AMANDA

ICECUBE

Answers in the sky?

Cold Dark Matter

Dark baryonicmatter (3.5%)

Normal matter: stars (0.4%)

Dark Energy

CosmicAccelaration

73%

23%

Dark matter

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Rotation curves of galaxies

( )( )

GM Rv R

R

34( )

3M R R

Note that4

( )3

v R R G

‘problem’ is known for a long time (Zwicky 1937)

Possible solutions:• Dark matter (Oort 1932)• Gravity (Bekenstein 2004)

Mass bending light

Albert Einsteinsir Arthur Eddington

Gravitational lensing,standard tool for investigating quasars

Matter and gas in bullet cluster

Optical

Matter and gas in bullet cluster

Optical X-ray

Matter and gas in bullet cluster

Gravitational

Optical

Matter and gas in bullet cluster

• Stars (1-2%)• Hot gas which interacts electromagnetically

and is pulled back in the collission (5-15%)• A lot of dark matter, which like the galaxies

interacts only gravitationally (> 80%)• No need for ‘abnormal’ gravitational effects

4700 km/s

720 kpc

What could this dark matter be?

• Gravitational anomaly improbable• But as for the matter, we simply don’t know

– Supersymmetric particles– Neutrino’s (righthanded ones), m > 4 eV/c2

– …• LHC, neutrino detectors or gravitational wave

detectors, unraveling cosmic rays, LOFAR, …

Going back further

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The CMB

T = 3 mK

T = 2.728 K

T = 20 K

• Uniform distribution

• A dipole effect corresponding to the motion of Earth with respect to CMB rest frame (about 600 km/s)

• Effect of our own galaxy (choosen as the equator of the projection)

• Quadrupole (Sachs/Wolfe)

• Absence of other mK variations gives support to inflation models and dark matter

,T 2.7248K 2.7252K

Temperature maps of sky

, ,lm lmaT Y ,T

2.7248K 2.7252K

l

Angular momentum Spectrum

0.4 100.3(6.5 ) 10baryonen

fotonen

N

N

Cosmology becoming a precision science

WMAP data

Future of CMB research

• COBE (1989-1993)• WMAP (2001-present)• Planck

Planck is part of the ESA Horizon 2000 Scientific Program. Its scientific goal is to measure the CMB anisotropies at all angular scales larges than 5-10’ over entire sky with a precision of 2x10-6

Planck has been launched in May 2009 and has been directed to the second Lagrangian point of the Earth-Sun System.

1.5 x 106 km

Present day view of cosmos

Rotation of galaxies Gravitational lenses Microwave background

and even further

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Multi-messenger approach:• Neutrinos (ANTARES, KM3NET)• UHECR (Auger, LOFAR)• Gravitational waves (VIRGO, LISA)

Gravitatiegolven: trillingen van ruimte en tijd

op aarde (VIRGO in Pisa)

in de ruimte (LISA)

Kosmische straling

HISPARC

AUGER (Argentinie)

EINDE

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