WHAT POWERED THE BIG BANG? WHAT HAPPENS AT THE EDGE OF A BLACK HOLE? WHAT IS DARK ENERGY? National...

WHAT POWERED THE BIG BANG?

WHAT HAPPENSAT THE EDGE

OF A BLACK HOLE?

WHAT ISDARK ENERGY? National Aeronautics and

Space Administration

Bin Wang 王斌Department of Physics

Fudan University

BEYOND EINSTEINBEYOND EINSTEIN

2005--Einstein Year


Top priority: Answer the most profound questions raised, but not answered, by Einstein.

Interesting:. . . accretion disks, Big Bang, black holes,

cosmic magnetic fields, cosmic rays, dark energy, dark matter, extreme environments, gamma-ray bursts,

jets, large-scale structure, microwave background,neutron stars, nucleosynthesis, relativity,

supernovae, . . .

1025 cm (UHE Cosmic Rays) to 1015 cm (Gravitational waves)

Great Decade: CMB fluctuations (COBE, BOOMERanG, MAXIMA, MAP, . . .) Gamma-Ray Bursts (CGRO, HETE-2, Swift, Glast, . . .) Ubiquity of black holes (Chandra, ASCA, HST, . . .)


Three startling predictions of Einstein’s relativity:

• The expansion of the Universe (from a big bang)

• Black holes

• Dark energy acting against the pull of gravity

Hubble discovered the expanding Universe

in 1929

Black holes found in our Galaxy and at the center of quasars over the past three decades

Evidence for an accelerating Universe

was observed in 1998

Einstein’s Predictions

Observations confirm these predictions . . . . . . the last only four years ago


Completing Einstein’s Legacy

BIG BANGWhat powered the Big Bang?

BLACK HOLESWhat happens at the edge of a Black Hole?

DARK ENERGYWhat is the mysterious Dark Energy pulling the Universe apart?

Beyond Einstein will employ a series of missions linked by powerful new technologies and common science goals to answer these questions …

… and launch the revolution of the 21st century!

Einstein’s legacy is incomplete, his theory fails to explain the underlying physics of the very phenomena his work predicted


What Powered the Big Bang?

Inflation(Big Bang plus

10-34 Seconds)

Big Bang plus 300,000 Years

Big Bang plus 15 Billion Years

What Powered the Big Bang?Gravitational Waves Can Escape from

Earliest Moments of the Big Bang

Nowgravitational waves

light


Gravitational waves leavea distinctive imprint onpolarization pattern of CMB

Vacuum energy poweredinflation-some form of it may be the “dark energy”

Gravitational waves frominflation and phase transitionsmay be detected directly

What Powered the Big Bang?

BEYOND EINSTEINBEYOND EINSTEINWhat we are currently trying to achieve in cosmology?

To obtain a physical description of the universe, including its global dynamics and matter content;

To measure the cosmological parameters describing the universe, and to develop a fundamental understanding of as many of those parameters as possible;

To understand the origin and evolution of cosmic structures;

To understand the physical processes which took place during the extreme heat and density of the early universe.

BEYOND EINSTEINBEYOND EINSTEINObservational Results from WMAP

Detection of large angle (50 l 150)

TE anti-correlation

Primordial Perturbations

两个重要结果：1, 跑动谱指数 (running)

nS=0.930.03

d nS/dlnk=


2, 小 l 压低

BEYOND EINSTEINBEYOND EINSTEINWhat we hope to learn from CMB?

An initial goal will be to test whether the simplest models of inflation continue to fit the data, meaning models with a single scalar field rolling slowly in a potential V which is then to be constrained by observations.

If this class of models does remain viable, we

can move on to reconstruction of the inflaton potential from the data.


What we hope to learn from CMB?Brane world

Are there modifications to the evolution of the homogeneous Universe?

Yes, RSII model Are inflationary perturbations different?

Yes Do perturbations evolve differently after they

are laid down on large scales?

Not clear yet


Close to a black hole event horizon, extreme distortions of space & time predicted by Einstein can be observed

Black holes are ubiquitous in the Universe

Chandra Deep Image

What Happens at the Edge of a Black Hole?


What Is a Black Hole?


Black Holes’ Hairs


SpaghettificationSpaghettification


A Black Hole Candidate



Image a Black Hole!

0.1 arc sec resolution

HST Image M87

Black Hole Imager 0.1 micro arc sec resolution

4-8 arc sec

Hubble, Chandra, and other observatories are showing black holes are common place

in the Universe

Black holes provide a unique laboratory to test Einstein’s theory of gravity

A future black hole imager with a resolution one million times Hubble will observe the

effects Einstein predicted

X-ray emission from close to the event horizon provides a powerful probe


What Happens at the Edge of a Black Hole?

• Japan-US ASCA satellite discovered iron lines near the event horizon of a black hole

• Line exhibits a strong redshift and provides a unique probe of the inner regions of black holes

• Black hole binaries produce gravitational waves in all phases of their evolution

• Test of GR in all three phases

X-Ray Spectroscopy

Gravitational Radiation


Do black holes have a characteristic “sound”?

Yes.Yes. During a certain time interval the evolution of initial

perturbation is dominated by damped single-frequency oscillation.

Relate to black hole parameters, not on initial perturbation.

IR i


What is the Dark Energy?

Einstein introduced the Cosmological Constant to explain what was then thought to be a static Universe, “my biggest mistake . . . ”

A surprising recent discovery has been the discovery that the expansion of the Universe is accelerating.

Implies the existence of dark energy that makes up 70% of the Universe

Dark Energy maybe related to Einstein’s Cosmological Constant; its nature is a mystery.

Solving this mystery may revolutionize physics . . .



1. 宇宙常数 w= -1

2. 常数 w> -1{ 宇宙弦（ w=-1/3)

畴壁（ w=-2/3) 特殊 k-essence

3. 动力学模型 {Qintessence

O(N) Qintessence Chaplygin gas K-essence Braneworld Wet Dark Fluid Chameleon 4. phantom


Dark Energy-----CMB Low l Suppress

We will use coordinates for the metric of our universe

The tendency of preferring closed universe appeared in a suite of CMB experiments

The improved precision from WMAP provides further confidence showing that a closed universe with positively curved space is marginally preferredA. Linde(JCAP03);Luminet(Nature03);Efstathiou(MNRAS03)

The spatial geometry of the universe was probed by supernova measurement of the cubic correctionto the luminosity distanceCaldwell astro-ph/0403003; B.Wang & Gong (PLB in press)


The Harmonic Function

The harmonic function satisfies the generic Helmholtz equation

For the flat space, the above Eq. can be solved by

2 2 0Q kD xThus the purely spatial dependence of each mode of oscillation in spherical coordinates is represented in the form

For the nonzero curvature space, the only change in the metric is in the radial dependence, thus in the curved space


The Harmonic Function

With our metric, the radial harmonic equation in the curved space is given by

For the requirement that is single valued, satisfying the periodic

boundary condition

CMB power spectrum.


HOLOGRAPHIC UNDERSTANDING OF LOW-l CMB FEATURE

The relation between the short distance cut-off and the infrared cut-off

Translating the IR cutoff L into a cutoff at physical wavelengths

we have the smallest wave number at present

The comoving distance to the last scattering follows from the definition of comoving time

f (z) relates to the equation of state of dark energy w(z)


CMB/Dark Energy cosmic duality

Thus the relative position of the cutoff is the CMB spectrum depends on the equation of state of dark energy.

Given the experimental limits,



CONSTRAINTS ON THE DARK ENERGY FROM THE LOW-l CMB DATA

Static DE

Dynamic DE



Dynamic DE



We do not know what 95% of the universe is made of!


X-Ray Sources: Hydra A Galaxy Cluster


34


MAP

LIGO

Hubble

Chandra

GLAST

Beyond Einstein ProgramS

cien

ce a

nd

Tec

hn

olo

gy

Pre

curs

ors


Gravitational Wave Astronomy

Black holes, neutron stars, and white dwarfs orbiting each other emit gravitational waves

Gravitational radiation from black hole mergers can be used to test

General Relativity

The real voyage of discovery consists not in seeing new landscapes, but in having new eyes. - Marcel Proust

BEYOND EINSTEINBEYOND EINSTEINLaser Interferometer Space Antenna (LISA)

LISA uses a laser based Michelson interferometer to monitor the separation between proof masses in separate spacecraft

• Three spacecraft separated by 5 million km

• Each spacecraft includes two freely falling test masses with drag free operation

• Distance changes measured with precision of 4 ppm RMS over 100 seconds

Flight demonstration of disturbance reduction system ST-7 on ESA

SMART-2 mission in 2006

Joint ESA-NASA project

LISA, the first space-based gravitational wave antenna, was given strong endorsement by US National Academy of Sciences McKee-Taylor and Turner Committee Reports

micro-newtonthrusters


Constellation-X

• 25-100 times sensitivity gain for high resolution spectroscopy in the 0.25 to 10 keV band

• Four satellites at L2 operating as one with advanced X-ray spectrometers

Enable high resolution spectroscopy of faint X-ray sources

• Black holes: Probe close to the event horizon Evolution with redshift

• Dark side of the Universe: Clusters of galaxies and large-scale

structure• Production and recycling of the elements:

Supernovae and interstellar medium

Constellation-X given strong endorsement by US National Academy of Sciences

McKee-Taylor and Turner Committee Reports

Use X-ray spectroscopy to observe


Royal Swedish Academy of Sciences 2002 Nobel Prize in Physics

Other Endorsements

Hulse & Taylor (1993); Fowler & Chandrasekhar (1983);Penzias & Wilson (1978); Hewish (1974); Hess (1936);

Einstein (1921)

“for pioneering contributions to astrophysics, which have led to the discovery of cosmic X-ray sources”

Riccardo Giacconi


Priority and science topic Dark Energy Probe• Inflation Probe• Black Hole Finder Probe

Competed Principal Investigator missions • Implementation approach determined by peer review• Launched every 3-4 years • $350-500M class missions

Einstein Probes

Three focused missions, each designed to address a single high priority science question


Major Initiatives:

1. NGST2. Constellation-X Observatory3. Terrestrial Planet Finder4. Single Aperture Far Infrared Observatory

Moderate Initiatives

1. Gamma-ray Large Area Space Telescope2. Laser Interferometer Space Antenna3. Solar Dynamics Observatory4. Energetic X-Ray Imaging Survey Telescope5. Advanced Radio Interferometry Between

Space & Earth

Astronomy & Astrophysics in the New Millennium


• Measure the polarization of the CMB

• Determine the properties of dark energy

• Use space to probe basic laws of physics

(Con-X, LISA)

• (Highest energy cosmic rays)

• (High-energy-density physics)

• (Interagency Initiative)

• (Neutrino masses)

Connecting Quarks with the Cosmos 2002 (Turner) Not a priority list.


Beyond Einstein Timeline


Education and Public Outreach

Beyond Einstein will address the international education priority by inspiring future generations of scientists

and engineers, as only WE can . . .

Big Bang and black holes capture the imagination

and can be usedto teach physical science

at all levels


How did the Universe begin? Does time have beginning & an end? Does space have edges? The questions are as old as human curiosity. But the answers have always seemed beyond the reach of science. . .

until now!

The 21st Century

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