physics 10, introductory lecture a. albrecht january 2010

Physics 10, introductory lecture

A. AlbrechtJanuary 2010

The Keck 10m Telescopes on Mauna Kea, Hawaii

Segments of the Keck 10m Telescope Mirror

1. Introduction (The “Golden age of cosmology”)

2. The Big Picture

3. The Edge of the observable universe

4. The mysterious dark side

Outline

Part 1

Introduction:The golden age of cosmology

The APM (Automatic Plate Machine) Survey (1992)

Sky positions of 2,000,000 Galaxies

The Sloan Digital Sky Survey(to locate over 100,000,000 galaxies, 3D positions for

1,000,000)

A simulation of just 65,000 Sloan galaxies

June 5 2001: First release of Sloan data (50,000 galaxies)

Plot of 78,000 SDSS galaxies

Sloan Survey Status

Imaging (Galaxy positions on the sky) 47% Complete Jun 21 2002

47,000,000 galaxy positions

Spectroscopy (3D galaxy positions) 34% Complete Jul 15 2002

340,000 galaxy positions

Sloan Survey Status

Imaging (Galaxy positions on the sky) 97% Complete Jun 27 2004


Spectroscopy (3D galaxy positions) 67% Complete Jun 27 2004


Sloan Survey Status

Imaging (Galaxy positions on the sky) 107% Complete Mar 13 2005


Spectroscopy (3D galaxy positions) 68% Complete Mar 15 2005


http://sdss.org

1993

2009

2003

Real

Simulated

Simulated

Maps of the microwave sky (the “edge of the observable universe”)

1993

2009

2003

Real

Real Data!

Simulated


Updated after WMAP announcement, Feb 2003

1993

2009

2006

Real

Real Data!

Simulated



WMAP 3-yr map

WMAP 5-yr map

First map from PLANCK satellite (2 weeks of data Aug 2009) superposed on optical map of the sky

http://www.esa.int/esaSC/120398_index_0_m.html

http://www.rssd.esa.int/index.php?project=planck

Mass inferred from lensing: Must have dark matter

Using Hubble’s new “advanced camera for surveys” June 2002

http://www.nasa.gov/mission_pages/hubble/main/index.html

http://hubblesite.org/

Some Future Plans

LSST (Large-aperture Synoptic Survey Telescope)

SNAP (Supernova / Acceleration Probe )

James Bock / NASA Jet Propulsion Laboratory Imaging Cosmic Microwave Background Polarization with EPIC We propose to study a mission concept, the Experimental Probe of Inflationary Cosmology (EPIC), based on a single-aperture telescope and receiver with high-sensitivity polarization-sensitive detector arrays.

Hubble ACS (Advanced Camera For Surveys)

Keck Telescope

Golden Age: Data + Theory

• Origin of the elements (“Nucleosynthesis”)

• What formed the galaxies?

• How the big bang got started (“Cosmic Inflation”)

Part 2: The big picture

First Step: Distances in the Universe

Measure of distance: One Kilometer ≈ Distance from the ARC to Roessler Hall

Count cosmic distances as grains of sand: One grain of sand per kilometer.

Grain of sand (enlarged)

Measure of distance: One Kilometer ≈ Distance from the ARC to Roessler Hall

Diameter of earth = 12,760 kilometers 1 Teaspoon of sand

Distance to Moon = 356,410 kilometers 1 Handful of sand

Distance to Moon = 356,410 kilometers 1 Handful of sand

(Also roughly the distance light travels in one second)

Distance from Earth to Sun = 149,600,000 kilometers (8 light minutes) 1 kitchen trash can full of sand

Distance from Earth to Pluto = 6,000,000,000 kilometers 1 wheelbarrow of sand

Distance from Earth to Nearest Star = 40,000,000,000,000 kilometers 1 dumpster of sand

Distance from Earth to Edge of our galaxy = 1,000,000,000,000,000,000 kilometers 1 Physics/Geology Bulidng full of sand

Average distance between galaxies = kilometers 1 baseball stadium full of sand

193 10

Average distance between galaxies = kilometers 1 baseball stadium full of sand

193 10

Number of 0’s after the 3

Farthest visible “object” in the universe: kilometers mountain range of sand

251 10

Number of 0’s after the 1

?

What we know about the big picture

1) On large scales the matter in the Universe is spread out very smoothly (“Homogeneous”)

Mean density:29 310 /gram cm

2) The Universe is expanding

Hubble law: v Hr

3 / sec

100

mH

lightyears

The homogeneity of the Universe

Isotropy of the microwave background (from the “edge of the observable universe”) to one part in 100,000

The homogeneity of the universe

Galaxy surveys

Radial Direction

We are here

The homogeneity of the universe

Galaxy surveys

Radial Direction

We are here

From 1986

The Hubble law

v Hr3 / sec

100

mH

lightyears

v

r

Hubble Expansion

Hot, Dense past

The History of the Universe Today

Galaxy Formation

Last Scattering

Nuclear & HEP

Inflation?

Extra Dimensions?

Time

High Energy & Temp

Anti-Gravity?*!

The History of the Universe Today

Galaxy Formation

Last Scattering

Nuclear & HEP

Inflation?

Extra Dimensions?

Time

High Energy & Temp

Anti-Gravity?*!

Research at UCD in all these areas!

Part 3: The Edge of the observable universe

The Edge of the Observable Universe:

As we look back in space we look back in time. We see:

Here & Now

Light traveling from far away =from distant past

Long ago (about 14 Billion years) the Universe was so hot and dense it was opaque: The edge of the observable universe

Today:• Only 2.726K above absolute Zero

• “Microwave Radiation” (The “Cosmic Microwave Background”: CMB)

• 1,000,000 times weaker than ambient radiation in a pitch dark room.

Properties of the Edge of the Observable Universe:

Here & Now

Similar to surface of Sun at time of emission

(~ 6000 )K

Observing the Microwave Background, Past, present and future:

The History of the Universe Time

High Energy & Temp

New Image of the “Last Scattering Surface” from NASA’s WMAP satellite released Feb 11 2003

2009


Real data

Simulated data

Real data !

1993

Maps of the microwave sky (the “edge of the observable

universe”

WMAP map of the “edge of the

observable universe”

plotted as a sphere

WMAP map of the “edge of the

observable universe”

plotted as a sphere

Note: we are really on the inside looking

out

NASA’s WMAP (Microwave Anisotropy Probe)

-Launched June 30 ’01

-Reached “L2” Oct 1 ‘01

Using the CMB to learn about the Universe

CM

B a

nis

otr

op

y p

ow

er

50

100

solid=inflation model

dashed=defect models

(magenta=desperate)

• Characteristic oscillations in the CMB power

Adapted from

Bennett et al Feb 11 ‘03

WMAP

“Active” models

Inflation

I.1 Successes

Tem

pera

ture

Pow

er

Angular scale

The Mysterious Dark Side

Cosmic acceleration

Using supernovae (exploding stars) as cosmic “mileposts”, acceleration of the Universe has been detected.

Supernova

Acceleration of the universe

The Hubble law at great distances depends on the variations of the Hubble “constant” H with time.

" "v

" "r

Cosmic acceleration


Supernova

Preferred by modern data

Amount of ordinary matter

A

mount

of

“anti

gra

vit

y”

matt

er

“Ordinary” non accelerating matter

Supernova


Amount of gravitating matter

A

mount

of

“anti

gra

vit

y”

matt

er

(Dark

En

erg

y)

Red line: No anti-gravity matter

Mass-Energy of the a Universe made only out of standard model matter

Surprise factor



Red line: No anti-gravity matter

Mass-Energy of the a Universe made only out of standard model matter

A

mount

of

“anti

gra

vit

y”

matt

er

(Dark

En

erg

y)

Need to add dark energy here

Need to add dark matter here

Cosmic acceleration (newest data)


Supernova



A

mount

of

“anti

gra

vit

y”

matt

er

“Gravitating” non accelerating matter

Supernova

Preferred by data c. 2003

Amount of “ordinary” gravitating matter A

mount

of

w=

-1 m

att

er

(“D

ark

energ

y”)


Cosmic acceleration

Accelerating matter is required to fit current data

Cosmic acceleration


Supernova Amount of “ordinary” gravitating matter A

mount

of

w=

-1 m

att

er

(“D

ark

energ

y”)



BAO

Kowalski, et al., Ap.J.. (2008)

Cosmic acceleration


Supernova Amount of “ordinary” gravitating matter A

mount

of

w=

-1 m

att

er

(“D

ark

energ

y”)



BAO

Kowalski, et al., Ap.J.. (2008)

(Includes dark matter)

Supernova



A

mount

of

“anti

gra

vit

y”

matt

er


Here for inflation

Accelerating “Dark Energy” is what makes U=1 (required to give consistency with inflation)

Acceleration or (required for inflation) is possible (+)

Dark Energy *very* poorly understood (-/+)

Dark Energy and Inflation

Supernova



A

mount

of

“anti

gra

vit

y”

matt

er


Dark Energy and the fate of the Universe

In the presence of dark energy, the simple connection between open/closed/flat and the future of the universe no longer holds

Dark Energy (accelerating)

70%

Dark Matter 25%

Ordinary Matter (observed in labs)

5%

95% of the cosmic matter/energy is a mystery. It has never been observed even in our best laboratories


70%

Dark Matter 25%


5%


Gravitating


Dark Matter (Gravitating)



American Association for the Advancement of Science

American Association for the Advancement of Science

…at the moment, the nature of dark energy is arguably the murkiest question in physics--and the one that, when answered, may shed the most light.

University of Chicago10 May 2006

Andreas Albrecht

The report from the Dark Energy Task Force

From the DETF reportFrom the DETF reportFrom the DETF reportFrom the DETF reportDark energy appears to be the dominant component of the physical

Universe, yet there is no persuasive theoretical explanation. The

acceleration of the Universe is, along with dark matter, the observed

phenomenon which most directly demonstrates that our fundamental

theories of particles and gravity are either incorrect or incomplete. Most

experts believe that nothing short of a revolution in our understanding of

fundamental physics will be required to achieve a full understanding of the

cosmic acceleration. For these reasons, the nature of dark energy ranks

among the very most compelling of all outstanding problems in physical

science. These circumstances demand an ambitious observational

program to determine the dark energy properties as well as possible.

10

From the DETF reportFrom the DETF reportFrom the DETF reportFrom the DETF reportDark energy appears to be the dominant component of the physical

Universe, yet there is no persuasive theoretical explanation. The

acceleration of the Universe is, along with dark matter, the observed

phenomenon which most directly demonstrates that our fundamental

theories of particles and gravity are either incorrect or incomplete. Most

experts believe that nothing short of a revolution in our understanding of

fundamental physics will be required to achieve a full understanding of the

cosmic acceleration. For these reasons, the nature of dark energy ranks

among the very most compelling of all outstanding problems in physical

science. These circumstances demand an ambitious observational

program to determine the dark energy properties as well as possible.

10

#1 on Science magazine’s list of “most compelling puzzles and questions facing

scientists today”

THE GOLDEN AGE

1) Dramatic progress in our understanding

2) Deep mysteries yet to be resolved (probably a revolution is require!)

3) A clear path forward

Phy 10- Cosmology

I will do my best to teach you as much as possible about this very exciting field.

physics 10, introductory lecture a. albrecht january 2010

Documents

sky slide

hawaii slide

outline slide

observable universe

yr map slide

big picture slide

dark matter slide

roessler hall slide