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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
97,000,000 galaxy positions
Spectroscopy (3D galaxy positions) 67% Complete Jun 27 2004
670,000 galaxy positions
Sloan Survey Status
Imaging (Galaxy positions on the sky) 107% Complete Mar 13 2005
107,000,000 galaxy positions
Spectroscopy (3D galaxy positions) 68% Complete Mar 15 2005
680,000 galaxy positions
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
Maps of the microwave sky (the “edge of the observable universe”)
Updated after WMAP announcement, Feb 2003
1993
2009
2006
Real
Real Data!
Simulated
Maps of the microwave sky (the “edge of the observable universe”)
Updated after WMAP announcement, Feb 2003
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
1996
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
Updated after WMAP announcement, Feb 2003
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
Using supernovae (exploding stars) as cosmic “mileposts”, acceleration of the Universe has been detected.
Supernova
Preferred by modern data
Amount of ordinary matter
A
mount
of
“anti
gra
vit
y”
matt
er
“Ordinary” non accelerating matter
Supernova
Preferred by modern data
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
Preferred by modern data
Amount of gravitating matter
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)
Using supernovae (exploding stars) as cosmic “mileposts”, acceleration of the Universe has been detected.
Supernova
Preferred by modern data
Amount of gravitating matter
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”)
“Ordinary” non accelerating matter
Cosmic acceleration
Accelerating matter is required to fit current data
Cosmic acceleration
Accelerating matter is required to fit current data
Supernova Amount of “ordinary” gravitating matter A
mount
of
w=
-1 m
att
er
(“D
ark
energ
y”)
“Ordinary” non accelerating matter
Preferred by data c. 2008
BAO
Kowalski, et al., Ap.J.. (2008)
Cosmic acceleration
Accelerating matter is required to fit current data
Supernova Amount of “ordinary” gravitating matter A
mount
of
w=
-1 m
att
er
(“D
ark
energ
y”)
“Ordinary” non accelerating matter
Preferred by data c. 2008
BAO
Kowalski, et al., Ap.J.. (2008)
(Includes dark matter)
Supernova
Preferred by modern data
Amount of gravitating matter
A
mount
of
“anti
gra
vit
y”
matt
er
“Gravitating” non accelerating matter
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
Preferred by modern data
Amount of gravitating matter
A
mount
of
“anti
gra
vit
y”
matt
er
“Gravitating” non accelerating matter
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
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
Gravitating
Dark Energy (accelerating)
Dark Matter (Gravitating)
Ordinary Matter (observed in labs)
95% of the cosmic matter/energy is a mystery. It has never been observed even in our best laboratories
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.