Download CERN, 31 January, 2001

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Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Large structures and Orders of Magnitude
10 7 m
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Sun (Eclipse)
corona
10 9 m
Sun ≈ 2x1030 kg ≈ 1057 (protons + neutrons)
nucleons
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Earth Orbit
10 11 m
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Milky Way
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Spiral Galaxy
100 000 light years
= 10 21 m
10 11 stars
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Galaxy Cluster (Hercules)
10 23 m
Thousands of Galaxies
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Hubble Deep Field
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
A Foamy Universe (bubbles 200 Mly across)
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Summary of the largest structures
10 21 m
10 22 m
10 23 m
10 11
galaxies
10 22
stars
10 24 m
10 25 m
Egil Lillestøl, CERN & Univ. of Bergen
10 26 m
CERN, 31 January, 2001
1080
nucleons
Dominated by Matter and Gravity **
(1011 galaxies, 1022 stars)
Described by General Relativity
(or Newtonian Mechanics)
** This is far from the whole truth !!
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
15 billions =
1.5 x 10 12
years ago
and since then
ever expanding
Where it all came from
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Will the Expansion ever stop ?
Inflation predicts a flat universe.
This means that the Density of Matter and Energy
equals the so called critical density
Ordinary Matter can account for only up to
5% of the critical density
Dark Matter Problems
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
The First Dark Matter problem:
these Galaxies should simply not exist !
So:
is there
invisible (dark) matter
around the
galaxy ?
Need a spherical halo of matter around the galaxy
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
speed
200km/s
measured
predicted
distance from center
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Gravitational lensing
Distant galaxy
109 light years
Foreground cluster
2x 109 light years
Observer
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Reconstruction of Mass Distribution
(250 times more matter than expected from light output)
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Large amounts of invisible (dark) matter
Can NOT be ordinary matter :
- does not interact with light
- does not interact with ordinary matter
- does concentrate around galaxies
and in galaxy clusters.
What is it ???
If the answer is Super Symmetric Particles,
LHC will find it !!
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
The Second Dark Matter problem:
The dark matter seems to make up
only 30-50% of the critical density
This may be linked with observations of
a possible accelerating expansion of
the universe at large distances.
Study of type 1a Supernovae
(1a Supernovae ≈ standard light sources)
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
1a Supernova:
accompanying star
Egil Lillestøl, CERN & Univ. of Bergen
white dwarf
CERN, 31 January, 2001
Far away* supernovae seem to be too far away !
Very difficult observations, but if true could mean:
Resurrection of Einstein’s Cosmological Constant,
or “Qintessence” - one more possibility of
Exotic Matter ????
Need more astronomical data
Need the LHC for a better understanding of
dark matter
* for specialists - red shifts z ≈ 1
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
The Smallest Structures
where Quantum Mechanics reigns, and
where particles are waves, and waves are particles
Heisenberg’s Uncertainty Relation:
(Dx)(Dp) ≈ h/(2p)
or (Dt)(DE) ≈ h/(2p)
h is Planck’s constant - a very small number, (6.6x10-34Js)
x is position, p is momentum,
t is time, and E is energy.
(Dx) means uncertainty in position, etc
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Constituents of matter
Electrons
(10-18 m )
see
Atom
nucleus
nucleon
quark
10-10 m
10-14 m
10-15 m
10-18 m
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Stable (ordinary) matter:
one up quark (charge +2/3)
one down quark (charge -1/3)
leptons
one electron
(charge -1)
one neutrino (no charge, “no” mass)
composite
particles
proton
nucleons
neutron
But for what do we need the neutrino??
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
The Forces of Nature
(what is a force?)
Newton and Gravity
Faraday and Fields
Forces as “Exchange” Particles
An important difference between Matter Particles and Force Particles:
M.P. obey Pauli’s Principle, i.e. only one particle for each quantum state.
F.P. does not have this constraint and can clump together.
This is why Matter appears to be Solid
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Is the Quantum World a Fuzzy World?
The answer is a clear
NO !
QM means that all the
qualities of the subatomic
world and by extension of
everything can be
exactly quantified !
Photon, g
E = hn
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Can not use light microscopes to study atoms !!!
Quantum mechanics tells us that
particles behave like waves and visa versa:
electron
l = h/p
Use electron microscopes
LEP the world’s biggest
electron microscope
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
High Energy electron-proton scattering
quark
electron
New Stuff from
E = Mc2
New, unstable particles, can NOT be explained
as made up of up and down quarks only.
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Creating New Matter with LEP
Need two more generations of quarks
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
How does a point in empty space know exactly
the variety of particles it can produce
and all their properties and their forces .... ???
Back to Heisenberg and Faraday:
Particles and Forces are Quantum Fields filling
every point of “Empty” Space (or the “Vacuum”).
The Fields materialize as Particles when
Energy is fed into this Vacuum.
Structures are temporary, the Pattern lasts for ever !
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Practical Units
electron
(energy U)
-
U= 1 eV
= 1.6x10-19J
(speed at positive plate
18 000 km/s)
+
1 Volt
1 keV =
1 MeV =
1 GeV =
1 TeV =
103 eV
106 eV
109 eV
1012 eV
LEP = 209 GeV
LHC = 14 TeV
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001
Einstein: E = Mc2
Special Relativity:
( E2= (pc)2 + (M0c2)2 )
pc
use units such that c =1
E (GeV or MeV)
p (GeV/c or MeV/c)
M (GeV/c2 or MeV/c2)
E
M0c2
Mproton = 0.931 GeV/c2 ≈ 1 GeV/c2
Melectron = 0.5 MeV/c2
( Mtop = 170 GeV/c2 )
proton diameter = length scale:
10-15 m = 1 fermi (femtometer)
Egil Lillestøl, CERN & Univ. of Bergen
CERN, 31 January, 2001