BlackHoles.ppt full 27 slides with photo

nothing escapes a black hole … or does it? In the 1970s, the physicist Stephen Hawking described a subtle process by which black holes can “evaporate,” with some particles evading gravitational oblivion. That phenomenon, now dubbed Hawking radiation, seems at odds with general relativity, and it raises an even weirder question: If particles can escape, do they preserve any information about the matter that was obliterated?

Leonard Susskind, a physicist at Stanford University, found himself at odds with Hawking over the answer. In this episode, co-host Janna Levin speaks with Susskind about the “black hole war” that ensued and the powerful scientific lessons to be drawn from one of the most famous paradoxes in physics.

Listen on Apple Podcasts, Spotify, TuneIn or your favorite podcasting app, or you can stream it from Quanta.

JANNA LEVIN: Historically depicted as inescapable voids, black holes have terrorized the popular imagination. Anything and everything that falls into a black hole is lost forever. Or so the story goes, according to Einstein’s general theory of relativity. This defining character of black holes came under scrutiny in the 1970s with a surprising challenge posed by a young and brilliant but ailing British physicist, Stephen Hawking.

Hawking realized that through a remarkable and subtle quantum process, black holes could evaporate, eventually exploding entirely in a burst of radiation. Even in this explosion, nothing can escape. The black hole seemed to take everything it had consumed with it into oblivion, including all quantum information. But where did it all go?

I’m Janna Levin and this is “The Joy of Why,” a podcast from Quanta Magazine where my co-host, Steve Strogatz, and I take turns exploring some of the biggest unanswered questions in math and science today.

[Theme ends]

LEVIN: Few understood the significance of Hawking’s results initially, but one scientist immediately recognized the crisis that would become known as the information loss paradox. He is here with us today, the famed physicist Leonard Susskind — Lenny to anyone who knows him. In today’s episode, Lenny leads us through the Black Hole War as we ask: Is there a quantum escape hatch from black holes? And will we ever know for sure?

Lenny is a professor at Stanford University and the founding director of the Stanford Institute for Theoretical Physics. He’s widely regarded as the father of string theory, has authored a number of phenomenal books, including The Black Hole War: My Battle with Stephen Hawking to Make the World Safe for Quantum Mechanics, and he’s well-known for his research on quantum field theory, quantum statistical mechanics and quantum cosmology.

Lenny, thanks for joining us on “The Joy of Why.”

SUSSKIND: Anyway, these ancients, a Frenchman and I guess an Englishman, had the idea that if a star was heavy enough, it would be so attractive — not in the sense of I’m attractive or you’re attractive, but in the sense of gravitational

1. Super Massive Black HolesSuper Massive Black Holes
A Talk Given By:A Talk Given By:
Mike EwersMike Ewers

2. Black Holes: A Theoretical Black Holes: A Theoretical
Definition (A Review)Definition (A Review)

An area of space-time An area of space-time
with a gravitational with a gravitational
field so intense that field so intense that
its escape velocity is its escape velocity is
equal to or exceeds equal to or exceeds
the speed of light. the speed of light.

The Important thing is The Important thing is
that this area can be that this area can be
of any size.of any size.

3. The Finite Speed of LightThe Finite Speed of Light

As you all know As you all know
(especially (especially
Contemporary Contemporary
people), That the people), That the
speed of light is a speed of light is a
finite value in a finite value in a
vacuum.vacuum.
(A black-hole-powered jet of sub-atomic (A black-hole-powered jet of sub-atomic
particles traveling at nearly the speed particles traveling at nearly the speed
of light out of the M87 galaxy) of light out of the M87 galaxy)

4. Escape Velocity, Density, and Escape Velocity, Density, and
Schwarzschild RadiusSchwarzschild Radius

In terms of In terms of
gravitational force, gravitational force,
every object has an every object has an
escape velocity as escape velocity as

vvescesc = = SqrtSqrt[[(2 G M)/r(2 G M)/r]. ].
From that From that
Schwarzschild Radius Schwarzschild Radius
can be easily found.can be easily found.

All comes down to a All comes down to a
matter of density.matter of density.

5. Thinking in Terms of General Thinking in Terms of General
RelativityRelativity

Einstein’s Theory of Einstein’s Theory of
General Relativity General Relativity
basically says that basically says that
gravity warps space gravity warps space
time.time.

Rubber Sheet Rubber Sheet
analogueanalogue

Down, up, and through the funnel. An Down, up, and through the funnel. An
embedding diagram is generally a good embedding diagram is generally a good
representation of a black hole's warping of representation of a black hole's warping of
nearby space-time. But such 2-dimensional nearby space-time. But such 2-dimensional
illustrations can also cause conceptual illustrations can also cause conceptual
problems. problems.

6. This is a simplified modelThis is a simplified model

The black hole no hair The black hole no hair
theorem shows that theorem shows that
mass, charge, and mass, charge, and
angular momentum angular momentum
are the only are the only
properties a black properties a black
hole can possess hole can possess

7. Types of Black HolesTypes of Black Holes

““Normal Sized” Black Normal Sized” Black
HolesHoles

Microscopic (Primordial) Microscopic (Primordial)
SizedSized

Super-Massive Black Super-Massive Black
Holes (On the order of Holes (On the order of
millions to billions of Solar millions to billions of Solar
Masses)Masses)

(Estimated 3 million solar (Estimated 3 million solar
masses for Milky Way masses for Milky Way
Black Hole)Black Hole)

8. How Normal Black Holes Come How Normal Black Holes Come
About (A Review)About (A Review)

Most Black Holes are Most Black Holes are
believed to come believed to come
about from the death about from the death
of massive stars.of massive stars.

9. Stellar Evolution (Brief)Stellar Evolution (Brief)

Star (Mass of Hydrogen) is massive Star (Mass of Hydrogen) is massive
enough (M > 0.1 Menough (M > 0.1 Msunsun ) to ignite fusion ) to ignite fusion

Star performs stable core fusion (first Star performs stable core fusion (first
H->HE) H->HE)

Cycle repeats if star is big enough until the Cycle repeats if star is big enough until the
core is Fe.core is Fe.

Star is in a kind of onion peel structure of Star is in a kind of onion peel structure of
elemental layerselemental layers

10. Supernovas!?Supernovas!?

After fusion cycles through and star’s core After fusion cycles through and star’s core
is Fe, if the star now is M < 1.4 Mis Fe, if the star now is M < 1.4 Msun sun , the , the
star will supernova as a Type II star will supernova as a Type II
supernova. Otherwise, it becomes a white supernova. Otherwise, it becomes a white
dwarf, supported by degenerate electron dwarf, supported by degenerate electron
pressure.pressure.

This mass limit for supernovas is the This mass limit for supernovas is the
Chandrasekhar limit.Chandrasekhar limit.

11. Black Hole or Neutron Star?Black Hole or Neutron Star?

If the star the went If the star the went
supernova was between supernova was between
1.4 and 3 M1.4 and 3 Msun sun , then the , then the
remnant will be a Neutron remnant will be a Neutron
Star supported by Star supported by
degenerate neutron degenerate neutron
pressure (Pulsar).pressure (Pulsar).

Otherwise, Otherwise,
MMfinal final > 3M> 3Msun sun , and the , and the
result is a black hole result is a black hole
because the is no source because the is no source
of outward pressure of outward pressure
strong enough.strong enough.

12. Where Could Super-Massive Black Where Could Super-Massive Black
Holes Exist?Holes Exist?

The only known The only known
places in the Universe places in the Universe
where there could be where there could be
enough mass in one enough mass in one
area is in the center area is in the center
of massive galaxiesof massive galaxies

Not believed to be Not believed to be
anywhere elseanywhere else

13. Quasars: What are They?Quasars: What are They?

In some places where point sources of radio In some places where point sources of radio
waves were found, no visible source other than waves were found, no visible source other than
a stellar-looking object was found (it looked like a stellar-looking object was found (it looked like
a point of like --- like a star does). These objects a point of like --- like a star does). These objects
were called the "qausi-stellar radio sources", or were called the "qausi-stellar radio sources", or
"quasars" for short."quasars" for short.

Later, it was found these sources could not be Later, it was found these sources could not be
stars in our galaxy, but must be very far away --- stars in our galaxy, but must be very far away ---
as far as any of the distant galaxies seen. We as far as any of the distant galaxies seen. We
now think these objects are the very bright now think these objects are the very bright
centers of some distant galaxies, where some centers of some distant galaxies, where some
sort of energetic action is occurring.sort of energetic action is occurring.

14. Active Galactic NucleiActive Galactic Nuclei

In some galaxies, known In some galaxies, known
as "active galactic nuclei" as "active galactic nuclei"
(AGN), the nucleus (or (AGN), the nucleus (or
central core) produces central core) produces
more radiation than the more radiation than the
entire rest of the galaxy! entire rest of the galaxy!
Quasars are very distant Quasars are very distant
AGN - the most distant AGN - the most distant
quasars mark an epoch quasars mark an epoch
when the universe was when the universe was
less than a billion years less than a billion years
old and a sixth of its old and a sixth of its
current size. current size.

15. Brief Review of case for Super-Massive Brief Review of case for Super-Massive
Black Holes in these observed AGNBlack Holes in these observed AGN

The Time Variation of The Time Variation of
AGNAGN

The Eddington The Eddington
Luminosity ArgumentLuminosity Argument

The Motion of broad The Motion of broad
line emission medium line emission medium
around the central around the central
corecore

16. How did Super-Massive Black How did Super-Massive Black
Holes come about?--theoriesHoles come about?--theories

From “Lumps” in the From “Lumps” in the
early universeearly universe

The “Stellar Seed” The “Stellar Seed”
ModelModel

Collapse of a whole Collapse of a whole
star clusterstar cluster

17. Lumps from the early UniverseLumps from the early Universe

In the “Big Bang” the In the “Big Bang” the
whole universe was in a whole universe was in a
really dense state. So really dense state. So
much that perhaps lumps much that perhaps lumps
could have formed and of could have formed and of
matter dense enough that matter dense enough that
a black hole was formed.a black hole was formed.

There was enough There was enough
surrounding matter that surrounding matter that
galaxies formed around galaxies formed around
the lumpsthe lumps

Could explain why Could explain why
pockets of interstellar gas pockets of interstellar gas
never became galaxiesnever became galaxies

18. The Stellar Seed ModelThe Stellar Seed Model

Provided that the Provided that the
surrounding surrounding
environment is environment is
sufficiently rich in sufficiently rich in
matter, a giant black matter, a giant black
hole could result in an hole could result in an
initial “stellar seed” of initial “stellar seed” of
10 M10 Msun sun produced produced
during a supernova.during a supernova.

19. Collapse of a whole clusterCollapse of a whole cluster

If the stars of a tight knit If the stars of a tight knit
cluster of the moderately cluster of the moderately
young Universe had all young Universe had all
relatively the same size relatively the same size
stars (above the stars (above the
Chandrasekhar Limit), Chandrasekhar Limit),
there would be quite a there would be quite a
few Black Holes forming few Black Holes forming
simultaneously causing simultaneously causing
smaller stars to be smaller stars to be
absorbed, and black absorbed, and black
holes to combine.holes to combine.

NGC 1850 to the rightNGC 1850 to the right

20. Some Characteristic of AGNSome Characteristic of AGN

Super Bright: AGN Super Bright: AGN
3C273 (an extreme 3C273 (an extreme
example) is L = example) is L =
4.8*10^12 L4.8*10^12 Lsun sun ..

Cosmic Optical JetsCosmic Optical Jets

Tidal forcesTidal forces

Cannibalism—they do Cannibalism—they do
eat, the source of eat, the source of
energyenergy

21. Optical Jets—Why?Optical Jets—Why?

The magnetic fields around The magnetic fields around
a black holes that are a black holes that are
thought to produce the thought to produce the
spectacular jets of high-spectacular jets of high-
energy particles rushing energy particles rushing
away from black holes away from black holes
come from the disk of hot come from the disk of hot
gas around the black hole, gas around the black hole,
not the black hole itself. not the black hole itself.

The jets are made by the The jets are made by the
Magnetic field of the matter Magnetic field of the matter
before it goes in the Black before it goes in the Black
Hole.Hole.

Emit Synchrotron radio Emit Synchrotron radio
signalssignals

Cygnus A Cygnus A

22. Tidal forces stretch farther, but are Tidal forces stretch farther, but are
weakerweaker

The tidal force is proportional to the The tidal force is proportional to the
mass of the black hole. In other words, mass of the black hole. In other words,
as the object gets more massive, the as the object gets more massive, the
force should get bigger too. But the force should get bigger too. But the
force is also force is also inverselyinversely proportional to proportional to
the the cube of the object's radiuscube of the object's radius. As the . As the
hole gets more massive, its size hole gets more massive, its size
increases, but because of the cube increases, but because of the cube
factor, the force factor, the force decreasesdecreases much much
faster than any possible mass increase faster than any possible mass increase
can account for. The result is that big can account for. The result is that big
black holes have weak tidal forces, black holes have weak tidal forces,
and small ones have strong tidal and small ones have strong tidal
forces.forces.

Frames from a NASA computer Frames from a NASA computer
animation depict one possible cause of animation depict one possible cause of
gamma ray bursts. A star orbiting a gamma ray bursts. A star orbiting a
black hole spirals in as it is shredded black hole spirals in as it is shredded
by tidal forces, generating an intense by tidal forces, generating an intense
burst of gamma and other radiation as burst of gamma and other radiation as
the its matter is compressed and the its matter is compressed and
super-heated on its way to oblivion. super-heated on its way to oblivion.

23. CannibalismCannibalism

Apparently, Quasars are Apparently, Quasars are
only active on order of only active on order of
100 million years100 million years
A dead quasar could be A dead quasar could be
revived with a new source revived with a new source
food—by colliding food—by colliding
galaxiesgalaxies
Proof—elliptical galaxies Proof—elliptical galaxies
have been found to be have been found to be
active in radio active in radio
transmissions as well.transmissions as well.

Collision Galaxies NGC 2207 & IC 2163Collision Galaxies NGC 2207 & IC 2163

24. Observations of Super Massive Observations of Super Massive
Black HolesBlack Holes

Radio observations at Radio observations at
various radio various radio
telescopestelescopes

X-ray observations X-ray observations
from the orbital from the orbital
Chandra ObservatoryChandra Observatory

Optical Observations Optical Observations
from Hubble Space from Hubble Space
TelescopeTelescope

25. PicturesPictures
NGC4261

26. Fate of Universe?Fate of Universe?

All Black Holes Evaporate over time due to All Black Holes Evaporate over time due to
Hawking RadiationHawking Radiation

Eventually the Universe will have no Eventually the Universe will have no
matter in a cold dark death and all there matter in a cold dark death and all there
will be left is radiation.will be left is radiation.

Evaporation Time:Evaporation Time:
1 * 10^-7 (M/M1 * 10^-7 (M/Msunsun)^3 Years )^3 Years
On order of 1* 10^20 yearsOn order of 1* 10^20 years

27. Picture ResourcesPicture Resources

www.usatoday.comwww.usatoday.com/...//.../wonderquestwonderquest/ 2001-08-22-black-holes.htm/ 2001-08-22-black-holes.htm

www.astronomynotes.com/gravappl/s8.htmwww.astronomynotes.com/gravappl/s8.htm

astrosun.tn.cornell.edu/courses/astro201/bh_structure.htmastrosun.tn.cornell.edu/courses/astro201/bh_structure.htm

www.aspsky.org/mercury/mercury/ 9802/lockwood.htmlwww.aspsky.org/mercury/mercury/ 9802/lockwood.html

www.abc.net.au/science/slab/ wormholes/default.htmwww.abc.net.au/science/slab/ wormholes/default.htm

www.glyphweb.com/esky/ concepts/stars.htmlwww.glyphweb.com/esky/ concepts/stars.html

http://heasarc.gsfc.nasa.gov/docs/objects/agn/agntext.htmlhttp://heasarc.gsfc.nasa.gov/docs/objects/agn/agntext.html

www.nature.com/nsu/020603/ 020603-1.htmlwww.nature.com/nsu/020603/ 020603-1.html

http://www.linnaeus.uu.se/online/fysik/makrokosmos/gifs/bigbangsmall.jpghttp://www.linnaeus.uu.se/online/fysik/makrokosmos/gifs/bigbangsmall.jpg

www.astrographics.com/GalleryPrints/ GP0053.htmlwww.astrographics.com/GalleryPrints/ GP0053.html

www.abc.net.au/science/news/ stories/s71464.htmwww.abc.net.au/science/news/ stories/s71464.htm

http://imagine.gsfc.nasa.gov/docs/science/know_l2/active_galaxies.htmlhttp://imagine.gsfc.nasa.gov/docs/science/know_l2/active_galaxies.html

www.scs.gmu.edu/~tle/ galaxy_galery.htmlwww.scs.gmu.edu/~tle/ galaxy_galery.html