Title: Dark Energy and the Accelerating Universe
1Dark Energy and the Accelerating Universe
- Beyond Einstein and the Big Bang
2Time Magazine Person of the Century
There are critical questions in cosmology whose
answers eluded Einstein
3The Standard Hot Big Bang Model
- Expansion of the Universe is a result of the Big
Bang - The Universe is about 15 billion years old
- After the Big Bang
- Inflation occurred between 10-35- 10-32 second
- The Particle Zoo emerged within 1 millisecond
- Baryogenesis era began after 1 millisecond
- Light elements synthesized within first 3 minutes
- Galaxies formed by 1 billion years
4Matter dominated universe
5Old Matter Dominated Universe
- Matter Composition
- Light elements created in Big Bang heavy
elements in stars - 13 baryons
- (1 stars, 12 molecular clouds, planets and
stellar remnants) - 0.8 neutrinos
- 86 dark matter (non-baryonic)
- 100 Total Mass-Energy Budget
6Energy dominated universe
7Now Energy Dominated Universe
- Matter Composition
- 35 Baryons Neutrinos Dark Matter
- Energy Composition
- 65 Vacuum (Dark) Energy
- 100 Total Mass-Energy Budget
8The New Standard Hot Big Bang Model
- The Universe is
- Flat no spacetime curvature
- Accelerating the expansion rate in the present
epoch is increasing
9Dark energy
10Dark Energy The Fundamental Nature of Matter
- Unexpected Discovery of Dark Energy leads us to
ask - What is it?
- Why is it there?
- Do we need new theories of space and time?
- Are there Mysterious Particles Permeating Space?
11Solving the Mystery of Dark Energy
- What is the connection between dark energy,
gravity and the fate of the universe? - Is general relativity the ultimate theory of
gravity for the universe?
12The Accelerating Universe
by Anne Field, STSCI
13Recent Discoveries
- Recent discoveries have revealed the fundamental
connections between the forces of nature and the
structure of universe - Distant Type Ia Supernovae
- Cosmic Microwave Background
- Galaxy Cluster Counting
- Theoretical Developments
14Supernovae
15Type Ia Supernovae
- SN Ia
- Are very bright light sources visible across the
Cosmos - Show that expansion of the universe is
accelerating through distance-redshift relation - Reveal evidence for a mysterious dark energy in
the universe - Will provide the first measurements of equation
of state of universe
16Cosmic Microwave Background
Cosmic microwave background
Dense quark-gluon plasma
17Cosmic Microwave Background
- Measures the geometry of spacetime
- Spacetime geometry depends on the mass-energy
density of the universe - Observation of a flat universe confirms some of
the predictions of inflation - a revolutionary theory with roots in particle
physics
18Large Scale Structure
19Large Scale Structure
- Measures the mass density in the universe
- Reveals matter density is less than half the
mass-energy density of a flat universe - SNe Ia CMB Large Scale Structure show that
dark energy and dark matter are more than 90 of
the mass-energy budget of the universe.
20Theoretical questions
"Nature is a perpetual circulatory worker,
generating fluids out of solids, and solids out
of fluids, fixed things out of volatile,
volatile out of fixed. Isaac Newton
"Once you eliminate the impossible, whatever
remains, no matter how improbable, must be the
truth." - Sherlock Holmes (by Sir Arthur
Conan Doyle)
Facts that at first seem improbable will, even
on scant explanation, drop the cloak that has
hidden them and stand forth in naked and simple
beauty. -- Galileo Galilei
"If we knew what it was we were doing, it would
not be called research, would it?" "The most
incomprehensible thing about the universe is that
it is comprehensible. - Albert Einstein
21Theoretical Questions
- Why is the energy density so small?
- 120 orders of magnitude too small and yet not
zero fine tuning? - Why now?
- the energy density is about equal to the energy
density coincidence? - Will these be answered by new theories beyond
Einstein?
22(No Transcript)
23Unveiling the Dark Energy
- Precision Cosmology
- Measuring the equation of state
- is it constant in time and space?
- Supernovae Are the Most Powerful Tools to
Discover the Nature of the Dark Energy
24Next Steps SNAP
magnitude - redshift
- SNAP is better than anything else for acquiring
images and spectra of thousands of SNe
w(z)
w0
equation of state
25Supernova Acceleration Probe
- Space observations of thousands of supernovae
will provide the vital breakthrough in precision
cosmology to characterize the dark energy - SNAP will measure the matter and energy
densities, WM WDE , with exquisite precision - SNAP will precisely determine the equation of
state of the universe as a function of time and
space
26Roadmap toward Dark Energy
Lightcurve Peak Brightness
Images
?M and ?DE Equation of State Dark Energy
Properties
Redshift SN Properties
Spectra
data
analysis
physics
27SNAP Timeline
Launch
Construction
Science
RD
2001
2004
2008
2009
28Bold Ideas, Innovative Tools
A Billion Pixel Imager
29 Students Today -Leaders Tomorrow
- Undergraduates work with scientists and engineers
at collaborating institutions. - Graduate Students gain immediate research
experience on the most exciting current science!
First class students become first class
scientists and engineers by using first class
instruments and techniques
30Education and Public Outreach
... if we do discover a complete theory, it
should in time be understandable in broad
principle by everyone, not just a few scientists.
- Stephen Hawking
31Education and Public Outreach
Scientists Engineers
Undergraduates Graduate students
SNAP / EPO Operations
Science Centers Classrooms Students Teachers
Partnerships
32- We Are on the Cusp of Major Advances That
Connect Particle Physics, Astrophysics and
Cosmology Which Are Leading to Breakthroughs in
Fundamental Physics.