Doug Singleton, CSU Fresno

August 2nd , 2018 Universidad de Colima

The Mysterious Dark Matter and

Dark Energy in our Cosmos

SNe 1994D (HST)

ANCIENT GREEK COSMOLOGY

RENAISSANCE COSMOLOGY

MODERN COSMOLOGY

DARK MATTER & QUINTESSENCE

COMPOSITION OF THE UNIVERSE

CONCLUSIONS: ANCIENT X MODERN

PLAN OF THE TALK

1. Greek Philosophy & Cosmology

Socrates (469-399 B.C.)

PreSocratics: Thales, Heraclitus,

Pythagoras, Parmenides, Zenon, Empedocles,

Filolau, Anaxagoras, Diogenes…

Thales (624-546 B.C.) Water - the basic element!

Empedocles : Water, air, earth & fire (4)

Filolau & others : 4 + Quintessence/Aether

3 GREEK COSMOLOGISTS

COSMOS = SOLAR SYSTEM + STARS

ImprovedGeocentric Model - Unified the system of

Epicycles, Equants and Deferents. 13-

volume series book – ALMAGEST!

Eudoxus (408-355 B.C.): Model

around anwith 27 spheres rotating

stationary earth

Aristotle (384-322 B.C.):

Model with 55 Spheres

Ptolemy (90-160 A.D.):

?

Aristotle (384 – 322 B. C.)

Major Figure of Greek Science

Politics,Ethics,History,Physics,Biology,Logic!

Cosmological Propositions:

Universe is Finite, Spherical and limited by the Stars Sphere

The Center of the Universe is the Earth, Spherical and Inert

Each Planet and also the Moon/Sun have their own Sphere

Neither vacuum nor time exist outside the Sky!

5 elements: Water, Air, Earth, Fire & Aether (Quintessence)

Quintessence is the matter of the celestial bodies

Geocentrism: Standard Cosmological

model for 16 Centuries!

Q: WHY WAS THE 5TH ELEMENT

(QUINTESSENCE) PROPOSED BY

THE GREEKS?

A: Because the moon seems to be heavy

but does not move to the center of the Earth

(Heavy bodies fall to the center of the Universe!)

Roughly speaking Quintessence was

hypothesized in order to solve a

problem of acceleration!

Purgatory

PARADISE THE EMPYREAN

HELL

JERUSALEM

Divine Comedy - Dante Alighieri (1320)

Greek Legacy

Christian View+

2. RENAISSANCE COSMOLOGY

Copernicus (1473-1543): Heliocentrism

Tycho Brahe (1546-1601): Precision

Astronomical Observations!

COSMOS ?

Giordano Bruno (1548-1600): Defense of an Infinite Universe. Earth was not the center.

“Other Universes”

Heretic - Executed in Rome (burned at the stake!)

KEPLER (1571-1630): Empirical Laws

describing the planetary motion

GALILEO (1564-1642)

Defense of Copernican

Cosmology (Telescope)

NEWTON (1642-1727): Universal Gravitation

Newtonian Cosmology (1692): “ The

Universe must consist of a large amount of masses

separated by large distances, that is, the Universe is

Infinite (Euclidean) with the matter concentrated in

parts due to the gravitational attraction”

3 laws of motion plus the lawof

Gravitation explained many

different phenomena....

• Motion of the planets around the

Sun

• Orbits of the Comets

• Fall of bodies, Tides, etc.

Solved the majority of problems

in Astronomy and “terrestrial

physics”.

The Newton laws unified and generalized the works of Copernicus, Tycho Brahe, Kepler and Galileo.

Infinite Universe Without Quintessence!

3. COSMOLOGY IN THE 20th CENTURY

DISCOVERY OF

THE UNIVERSE

EXTENSION AND

ITS

COMPLEXITY!

MODERN COSMOLOGY...

EINSTEIN

FRIEDMANN

HUBBLE

PENZIAS-WILSON

SUPERNOVAS

QUINTESSENCE?

(DARK ENERGY)

1917 Static Universe

1922 Big-Bang Model

1929 Expansion Discovery

1965 Radiation of 3 K

1998 Accelerating Universe

Contemporary

BUT ! Einstein thought the Universe was Static.

In1917, to permit a

static, non - expanding

Universe, Einstein

invented the

“Cosmological Constant”

Λ

Later was discovered that

the Universe was

expanding!

The Expanding Universe

Zs. f. Phys. 10, 377, 1922

A. A. Friedmann (1888-1925)

Repercussion of Friedmann’s Article

Zs. f. Phys. 11, 326, 1922

Finally!

Open

Time70 Billions yrs

Sca

lefa

cto

ra

(t)

Flat k=0

Einstein-de Sitter (1931)

Closed k=1

(Friedmann, 1922)

(Friedmann, 1924)

The Early Universe Was

Smaller , Denser , Hotter

sEdwin Hubble (Expansion – 1929)

vH0d (H0 Hubble'sconstant)

THE OBSERVED UNIVERSE

• Basic Cosmological Parameter:

H0 - Hubble Constant

q0 - Decelerating Parameter

i - Density Parameter

22a 0 H0

k 1 i total

i

oa

ttoH

a|

o ttoa2q

aa|

c

i tto

i |B , , , DM , Q, tot

PROBLEMS IN COSMOLOGY

Universe with 3 known substances (1970)

1) Normal Matter (electrons & nucleons)

2) Radiation (CMB)

3) Neutrinos

2 Unknown (and Strange) SubstancesDARK SECTOR!

DARK MATTER (1972)

DARK ENERGY QUINTESSENCE (1998)

• Beware of the Dark Side…

Master Yoda

On the Dark Sector...

How do we know that

Dark Matter exists?

We infer the DM existence through its

influence on gravitationally bounded

systems in several scales of interest

Rotation Curve M33

R (kpc)105

v (km/s)

100

50

Expected from

Luminous disk

observed

DM 1. Galaxy Rotation Curves

V(r) = [GM(r) /r]1/2

30

DM 2: Gravitational Lensing in Clusters

What is the nature of Dark Matter?

Dark Matter is nonbaryonic!

b 0.04

0.5 bDM

Primordial Nucleosynthesis (Deuterium)

Late 60’s:

b 0.0449 0.0028

DM 0.222 0.026 b

Compare to WMAP-Planck results (1σ )

Peebles 1968

0.04

WHAT ABOUT DARK ENERGY?

1998

18 December 1998

Measuring Distances By Brightness

Use Supernovae As

Standard Light Bulbs

LUMINOSITY DISTANCE

For “Standard” Light Bulbs

Faint Distant

Bright Close

35

Distances with SNe Ia (main advantages)

SNe are “Light Balls” ! LSNe 1010 LSol

Their luminosities (L) and (F) are known

Spectral Information redshift z

The Hubble diagram can be drawn (H0 , q0)

Unified Sample (740 SNe) – Amanullah et al. ApJ, 2014

Information on the density parameters (ΩM, ΩΛ)

The best standard candles (1998 – 2016)

Ideal to estimate cosmological parameters

L

L)1/2

4Fd (

Supernova is the Explosion of a Star

Riess et al astro-ph/9410054

Hubble’s

data

85 SNe

local13 Distant

SNe1 Very

Far

1998: Acceleration! (Riess et al. 1998)

1) Acceleration

2) Subtraction

TOTAL= 1 (CMB)

Models with

= 0.3 (LSS + …)

= 1 0.3 = 0.7

Present View

Descoberta!

PerlmNobuel Ptterize -

2r011– Schmidt

- Riess

19

98

Visão Corrente

1998

Perlmutter – Schmidt - Riess

Nobel Prize - 2011

Present View

41

SOURCE OF ACCELERATION?

•Normal Matter implies deceleration

because Gravity is an attractive force!

• Negative Pressure accelerates the Universe

(RELATIVISTIC EFFECT! )

• Quintessence:

The energy density is positive but

its pressure is negative.

scale

facto

ra(t

)

time

Newton

a G 3panormal

3p 0Einstein

Dark Energy?

a 0

3p 0

acceleration

time

a 0

scale

facto

ra(t

)

Negative

Pressure!

Lensing

CMBSNe Ia

X- Ray

LSS

DE 70%

DM 25%

Quintessence:

70%

Stars:

0.5%

Hydrogen +

Helium: 4%

Heavy

Element:

0.03%

Dark Matter:

25%

Neutrinos:

0.3%

Composition

of the Cosmos

?

CONCLUSION

Basic vision of the Cosmos changed with the

development of Physics and Astronomy:

• The current Universe is accelerating (1998)

• Supernovas are the best probe (other evidences)

• 2 unknown substances: DM/DE (Quintessence)

Greeks were partially correct! TheUniverse has 5 basic “elements”:

Photons, Baryons, Neutrinos,

Dark Matter and Quintessence!

THANK YOU!

25

Martins, Lima & Chimenti MNRAS 2015

Rotation Curves for 24 galaxies

Gas -

Stars –

DM -

Distant galaxy

Observer

Galaxy clusters

(Gravitational lens)

Light rays are deflected by gravity

Dark Matter 2: Gravitational Lensing

c2 R

4GM

Light ray equation: u2

c2

3GMd 2uu

d 2

1 , 7 5 ' ' d e a r c o

Evidence 2. Gravitational Lensing

Aparent Position

Real position

relativistic correction

M

Fonte

Observador

Lens

GRAVITACIONAL LENSING

Image

ImageLens

Observer