Week 4 The Large Scale Week 4 The Large Scale UniverseUniverse

Galaxies, Cosmology,

The Theory of Everything

Our Galaxy – from the InsideOur Galaxy – from the Inside

In visible light

And in IRAnd in IR

Our Galaxy in HistoryOur Galaxy in History

Discovery– 200 years ago

astronomers assumed stars were evenly distributed through space!

– 100 years ago – we were the center of a disk of stars

Our GalaxyOur Galaxy

Variable stars were the trick– RR Lyra and Cephid = Henrietta Leavitt

Instability Strip on H-R Diagram upper right Period Luminosity Relationship right Hubble in 1923 found Cephids in other galaxies =

same distance calculations but on an intergalactic scale!

Our Galaxy Our Galaxy pg 542-543pg 542-543– Galactic Structure

right top A Center (nuclear

bulge) right bottom Disk Halo below

Open clusters vs. Globular Clusters

Galactic StructureGalactic Structure Mass of a Galaxy

Not only is the overall mass important, but the distribution of mass

Disk orbits and Halo orbits lower left

Dark MatterDark MatterKeplerian motion is expected

– Falls apart at the outer edge!– DARK MATTER– A form of matter that does not react to E-M forces, or

the Strong or Weak nuclear forces… only gravity A Halo around the galaxy Extends as far as 7X the visible radius of the galaxy Contains 10-100X the mass of the visible galaxy in it! But we can see through it! Particles? Another force? A problem here and elsewhere.

Dark Matter and GalaxiesDark Matter and Galaxies

Galactic StructureGalactic Structure

Formation– Similar to the Solar System

Theory in principle right– Age

From oldest open clusters = 7 billion years

From globular clusters (Hipparcos observations) = 11 billion years

Stars in the disk have metals (things heavier than Hydrogen and Helium), stars in the halo are almost entirely Hydrogen and Helium)

Formation of GalaxiesFormation of Galaxies

Dark Matter a factor as well?

Galactic ArmsGalactic ArmsWe are in the Orion-Cygnus Arm

– The next arm out is centered in Perseus (near Cassiopeia), the center of the galaxy is in Sagittarius

– Radio observations give us much of this structure (since light can’t get through the dust)

– The arms are NOT solid objects held together by some force

More Galactic StructureMore Galactic StructureSpiral Arms make up the outer reaches of our

Galaxy

What makes arms?What makes arms?

– Best theory = the Density Wave Theory- they are like sound waves/shock waves traveling through the disk

– O and B stars live their short lives before the wave passes (so we see the brightest stars

– BUT what starts the waves? How do you get branches? = Unknown.

More Galactic StructureMore Galactic Structure The Nucleus:

– Core region about as big as the full moon in our sky– Massive Black Hole = 2.7 million star mass!!– Stars 860 AU away circle the core in 16 years!!!– Event Horizon (Schwarzschild Radius) = 13X larger

than our sun in size.

In the CoreIn the Core

The Core of the GalaxyThe Core of the Galaxy

Galaxies in GeneralGalaxies in General Arms and Stars= TYPES of Galaxies

– Elliptical Galaxies left– Spiral Galaxies + Barred Spirals center– Irregular Galaxies lower right– NEW! Dark Matter finding!!

Spiral Galaxy Zoo MembersSpiral Galaxy Zoo Members

Elliptical Elliptical GalaxiesGalaxies

And Irregular GalaxiesAnd Irregular Galaxies

An old ideaAn old idea Edwin Hubble = Evolution Diagram

– E0 (round) to E7 (flat) elliptical– S0 (part elliptical and part spiral) , Sa to Sc – looser spiral– SBa to SBc lower barred spiral– Irr Irregular

A better structure- by age aloneA better structure- by age alone

Galactic Galactic Winds – Winds – Young Young

GalaxiesGalaxies??

More on thislater…

Galaxies in GeneralGalaxies in GeneralDistances to the Galaxies

– Light years and parsecs are too small now – We’ll use megaparsec (Mpc)

– One Mpc = 3.26 million light years or 2x1019 miles– Cepheids can be seen for 200 Mpc

(.6 billion light years = the universe is about 14 billion light years in radius)

Cepheid VariablesCepheid Variables

Far Out GalaxiesFar Out Galaxies

– Beyond this we have to use the overall brightness of galaxies themselves (similar shape and detail)

– Supernova can help too (but are rare)

– LOOK BACK TIME (Moon = 1.3 seconds, Sun= 8 minutes, Alpha Centauri = 4 years, Andromeda Galaxy 2 million years, The ‘edge’ of the universe = 13.7 billion years)

Out = Out = back in back in

timetime

Looking Out at GalaxiesLooking Out at Galaxies

The most distant galaxies visible = 3000 Mpc (10 billion light years)

The Hubble Law– Vr=Hd (Vr= velocity of galaxy away from us, d=

distance in Mpc, H = Hubble Constant (km/sec/Mpc)

– Newest results put H near 70-80 km/sec/Mpc 71 ± .4 km/sec/Mpc EVEN MORE RECENT from

WMAP

Hubble Velocity-Distance Hubble Velocity-Distance RelationshipRelationship

The Ladder of DistancesThe Ladder of Distances

Looking Out at GalaxiesLooking Out at Galaxies

OTHER CRITTERS– Colliding Galaxies

Active Galactic Nuclei Active Galactic Nuclei – Galaxies with Active Nuclei – wind again

Pump out radio and X-ray radiation and jets (from the central Black Hole)

– Comes from Collisions = newest theory

QuasarsQuasars

– Quasars Special active nuclei cores near the

beginning of the universe (the furthest things visible in the universe)

Moving away from us at a good fraction of the speed of light!!!

Massive Black Holes Gravitational lens (Einstein)

A good A good quasar!quasar!

Jets are common

The discovery of quasars…The discovery of quasars…Incredible Red Shift!!

A distant A distant quasar, quasar,

core out-core out-shines it’s shines it’s disturbed disturbed galactic galactic

armsarms

Two lobes (in radio light) Two lobes (in radio light) ejected from a galactic coreejected from a galactic core

Artists Artists conception conception of an active of an active

galactic galactic nucleinuclei

AT the core of it… massive AT the core of it… massive black holesblack holes

Artist’s Interpretation

How the massive Black Holes at the How the massive Black Holes at the Galactic Centers make the JetsGalactic Centers make the Jets

How do we find massive How do we find massive galactic black holes?galactic black holes?

That takes us to the edge of That takes us to the edge of stellar light. Lets look at the stellar light. Lets look at the

universe itself!universe itself!

The Structure of the UniverseThe Structure of the UniverseThe Structure of the Universe

– Clusters of Galaxies 2700 clusters within 4 billion light years Rich galaxy clusters = >1000 galaxies Poor galaxy clusters = < 1000 galaxies See the Hubble Deep Sky Image… next two frames

Ultra Deep Field ImageUltra Deep Field Image(near Orion, abt. 1 square)(near Orion, abt. 1 square)

Close-up HUDFClose-up HUDF

But does it go on forever?But does it go on forever?Is the universe infinite as Is the universe infinite as

Einstein assumed?Einstein assumed?

The Structure of the UniverseThe Structure of the Universe– Olber’s paradox - not an infinite universe

The Universe as a WholeThe Universe as a Whole

– Assumptions of cosmology Homogeneity = (distribution) Isotropy = (looks the same) Universality = (laws) Cosmological Principle = (other observers would

see the same stuff)

ExpansionExpansionEinstein and the geometry of Space –

Time– The universe is expanding (Hubble et.al.)

But not INTO anything lower leftThere is more empty space all the time

(dense regions not expanding)Red Shift from expansion rightSpace time is Curved – but how?

Universal Universal GeometryGeometry

– Finite but unbounded – like a GLOBE = favorite OUT

– Infinite and unbounded – like a piece of paper - forever

So is there an edge?So is there an edge?

Arno Penzias and Robert Wilson – Bell Laboratories around 1965

Detected the Cosmic BackgroundRadiation

Cosmology- The Big BangCosmology- The Big Bang– The Big Bang – why is it the

best theory? Primordial Background

Radiation– Echo or remains of early HIGH

DENSITY time

– 2.7 Degree glow (remember Weins Law = peak radiation and temperature) No emission lines since it was a compressed universe. Just temperature

Present expansion and distribution of material - COBE

Darkness between galaxies (Olber)

WMAP mapWMAP map NASA/WMAP Science Team

Average temp = 2.725K (-455F) – Red = 0.0002 degrees warmer than the blue areas)

Old vs. Old vs. NewNew

NASA/WMAP Science Team

What What WMAP WMAP seessees

NASA/WMAP Science Team

Breaking NewsBreaking News

Newest findings…

The most important PPT slide in 100 yearsThe most important PPT slide in 100 years

WMAP Results– Space all across the universe is flat, parallel lines never meet.

The inflation theory underlying the Big Bang is correct. The universe continues infinitely far beyond our horizon.

– The universe is a mixture of 4.41 ± 0.3% normal baryonic matter, 21.4 ± 2.7% dark matter, 74.2 ± 3% dark energy (anti-gravity like force)

– Dark matter is ‘cold’ not ‘hot’ or ‘warm’. Neutrino limits set.– The universe is 13.73 ±0.12 billion years old (best yet)– Hubble Constant = 70.1 ±1.3 km/sec/mpc– Maximum “Z” (CBR) = 10.8 ±1.4– First stars turned on only 100-400 million years after big bang– The large scale filaments of galaxies are frozen remains of the

subatomic sized universe = quantum fluctuations

Make-up of the UniverseMake-up of the Universe

What does What does a Flat a Flat

Universe Universe Mean?Mean?

What does the ant see on a surface that is really a larger and larger sphere?

What if the sphere is nearly infinite in size?

Cosmology – The Big BangCosmology – The Big Bang

Before the Big Bang? – Another universe – bounce?– Our universe? (Finite and unbounded in time?)– Depends on your favorite theory!

The History of the Big BangThe History of the Big Bang– ‘Nothing’ at first – then it begins– 1/10,000,000 ths of a second = 1 trillion (1012)K , 5x1013

g/cm3)– No matter- just energy (light)– More matter than anti-matter made by a small margin (1

billion to one)– 4 seconds = all protons and neutrons made (cooled out)– 2 minutes = deuterium could form – Nuclear reactions (like in stars) formed helium– 30 minutes nuclear reactions ended (too cool now)– 1 million years –up to here a bright radiation dominated

universe– Atoms formed – electrons could be caught T= 3000K then

TRANSPARENT! What COBE/WMAP see, the 2.725K background radiation glow.

Cosmology in the EndCosmology in the End

– The end of the universe? – Critical Density

– 4x10-20 g/cm3

Options– Closed universe (Big Crunch someday)

– Open Universe (Heat Death) favored

– Oscillating Universe (bouncing re-creation)

– More on this later…

The makeup of the universeThe makeup of the universe– Dark Matter (2001 vs. 2005)

Apparently 90-99% of the universe is Dark Matter (Now 21.4 ±2.7%)

The visible universe is only the tip of the iceberg! (Now 4.41 ±0.3%)

Dark Energy (Now the remaining 74.2% ±3%) MACHO’s – massive Compact Halo Objects

(Elliptical vs. Spiral) Gravitational lensing again

A Quantum Universe – Refinements of the Big Bang Theory Big Bang problems

– Flatness problem – we are balanced on the open/closed boundary– Isotropy- background radiation is too smooth 1 part in 1000 perfect!

• The horizon problem- same temperature but no connection A Solution = inflationary period – makes it flat

The Grand Unification TheoryThe Grand Unification Theory

– The Grand Unification Theory

Another way to look at it…Another way to look at it…

Zero Point Energy and Zero Point Energy and Freezing ForcesFreezing Forces

In cosmology, the vacuum energy is taken to be the origin of the cosmological constant (dark energy(?)). Experimentally, the zero-point energy of the vacuum leads directly to the Casimir effect, and is directly observable in nanoscale devices.

Putting it Putting it all all

togethertogether

What is the CBR glow?What is the CBR glow?

It is the place back in time that we see the moment the universe became transparent.

It was a solid then too thick or opaque before then… we can’t look farther.

What else does a GUT help?What else does a GUT help?

Einstein's General Relativity and Quantum MechanicsDon’t Play Nicelyin Black Holes

The singularity is the problem

Re-fresh of Einstein and Re-fresh of Einstein and GravityGravity

Different Gravitational Different Gravitational StrengthsStrengths

GUTsGUTsEinstein et. al.

All velocities are relative (Special Theory)

Space and time are both aspects of the same thing Acceleration pull and gravitational pull are indistinguishable (General Theory)

Energy and Matter are the same (E=mc2) LATER- Space-time curvature is energy

(Superstring theory) General Relativity and Quantum

Mechanics DON’T MIX! Within the atom either. Or do they?

Super Duper StringsSuper Duper Strings

– Superstring theory Four forces

– Strong = Gluon

– Electromagnetic = Photon

– Weak = Weak gauge boson

– Gravity = Graviton

3 Families of 4 particles each– Electron, Electron neutrino, Up-quark,

Down-quark

– Muon, Muon neutrino, Charm Quark, Strange Quark

– Tau, Tau neutrino, Top Quark, Bottom Quark

Grand Unification IIGrand Unification IINo room in the inn

– Strings make properties of the particles via their vibrations, but not enough room in 3 or 4 dimensions

– More dimensions allow us to link the forces– 10 needed (3 space, 1 time, 6 curled up space) to go

to gravity– Curled up below the sub-atomic scale previous page– Calabi-Yau Shapes = 10,000’s which one?

next page

Curled up higher dimensionsCurled up higher dimensions All these force particles and particles

are made up of strings : 10 dimensions curled up

And this solves the infinities at the smallest scales… Relativity and Quantum Mechanics can merge

M-TheoryM-Theory The attempt to unify everything has lead down five

roads so far… M-Theory – adds 1 more dimension = 11

– Add one more dimension and you have a linking of the major theories! NOT FINISHED YET! 10-20 or 100 years???

– The blind men and the elephant…

Other Uses for Strings?Other Uses for Strings?

Cosmic Strings – can cause gravitational lensing, can account for missing mass in universe

Can create time travelBlack Holes and Time Travel

Gravitational LensingGravitational Lensing

The first great test of The first great test of Einstein’s TheoryEinstein’s Theory

LensingLensing

Einstein Cross

Einstein Ring

There is just one galaxy or quasar in the background

TimeTime

StringsStringsand Timeand Time

A nod to branesA nod to branes

Recent work (2003+) has now bounded the higher dimensions by membranes (branes) that.

p-branes (fill in your own # of dimensions for “p”) We might be in a 4-D universe

(3 space + 1 time) that is next to another4-D universe separated by a 5th dimension

The other 4-D universe is a ‘shadow’ universe where gravity is rooted

Parallel UniversesParallel Universes

There are many flavors:

The Other The Other You’sYou’s

Implications of an infinite flat universe

10115

10 meters

Quantum WeirdnessQuantum Weirdness

One way that the math in the quantum world works well is if you add up ALL the POSSIBLE paths of a particle and see how they interact.

So there ‘might’ be a universe for every alternate possibility – a universe where you are following out every choice you ever made and could have made.

Freaky Interference again?Freaky Interference again?This is another way to explain how particles

can form this interference pattern, even if only one is let through the two slits per hour for weeks on end!

Another possible Big BangAnother possible Big Bang

This leads us to the possibility that the big bang wasn’t a tiny dot that expanded.

The universe might have thinned out and thinned out until a ‘parallel’ universe just fractions of an inch away could close and touch our universe.

This would have filled the universe with a tremendous amount of energy that then would expand away. Just like the Big Bang! But different!

Then end is different then – a big expansion then another BANG! Next Slide!

Here comes the braneHere comes the brane

LinkToAnimation

Dark Energy and the END!Dark Energy and the END!

The expansion rate of the universe is unsteady…and is accelerating.

Eventually it will dominate the universe… everything will be torn apart to photons… then start over again.

UPDATE: Newest observations hint that normal expansion, not the ‘tearing apart of even atoms’, will occur.

Another version of reality…Another version of reality…

Information is King

Closely realted to: Information theory Quantum Gravity Loop Quantum Gravity

Subtitled:Subtitled:

All the uses for a simple looking equation:

S= k log w

RedundancyRedundancy

We deal in information The information we work with is filled with

redundancy.– Language (think of static on the radio)– Addresses (zip code + 4)– Internet protocols (duplex)– Pictures/vision (can make out images through

fog/static/snow/tall grass)– Code breaking (look for ‘rules’ in language)

An example of a simple law of An example of a simple law of physicsphysics

A Heat EngineLaw of thermodynamics(Entropy S=k log W )

The 3 Laws of The 3 Laws of ThermodynamicsThermodynamics

1st law= Energy can’t be created or destroyed = you can’t win

2nd law= The universe is moving towards an equilibrium = you can’t break even (no perpetual motion machines)

3rd law = You can’t cool anything to absolute zero = there is always some information in any system – you can’t go broke.

EntropyEntropy

EntropyEntropy The number of ways you can organize things in a space. Bell curves!!

These show up in-– Grades– People heights– All over the natural world– MUCH of the world is actually

a STASTISTICAL phenomena

Bell Laboratories againBell Laboratories again

Claude Shannon – – Asked: How much information can you

squeeze into a telephone line? What is the max?

– Think of Paul Revere = red light, green light– 1 light, 2 bits of information (land, or sea)– 2 lights = 4 (RR=land, RG=sea, GR=train,

GG= car)

Claude and beyondClaude and beyond

3 lights (RRR = land, RRG= sea, RGR=train, RGG = air, GRR = hovercraft, GRG=spaceship,GGR= teleportation, GGG = on backs of evil angels) --- 8 bits!

He found that when you have a question with N possible outcomes, you can answer it with only log N bits (letters).

Or x= log N - N= number of sounds or bits, x=the maximum information you need to carry.

Talk talk talkTalk talk talk

Everything done on a computer is done with letters of 0 and 1.

Everything done in your genetic code is done with 4 letters (GCAT).

Our language = 26 letters = vast number of words! But the maximum information you can carry is

log N, and Entropy = k log W (k= a constant, W = the number of possible states)

Entropy againEntropy again

So Entropy is really the measure of information!

EntropyEntropy

There is only a few ways to have a perfect egg – a few bits, but many many many ways to have a smashed egg.

Enter – EinsteinEnter – Einstein

Relativity says that nothing can go faster than the speed of light, and that the phenomena you observe depends on your viewpoint (more so at great speeds).

Barn and pole relativity experiment:

Close the barn door!Close the barn door!

Answer: the view from the observer and the runner is DIFFERENT= relative! It all comes down to the transmission of information!!!

Back to the subatomic worldBack to the subatomic worldEverything is quantized in the subatomic

world where bits of matter are BOTH waves and particles (wave-particle duality – remember?)

Superposition Superposition a way to get wave/particle thingsa way to get wave/particle things

Schrödinger's Cat

Without infoon a subatomicparticle (or a cat),it becomes bothor all states at once!

Alive AND Dead Observation makes

the probability cloudcollapse

InformationInformation

Again – getting an observation of the cat, electron, nucleus, etc. collapses the probability wave for an instant…all other possibilities go away.

But all those other possibilities interact with the world! (Think of the two slit experiment again… one photon a week = the same pattern!!)

The power of quantum The power of quantum computerscomputers

If we leave the atom or electron or photon UNOBSERVED, then it remains in superposition (all possible states at once).

Instead of an 8 bit computer, 16 bit, 32 bit, 64 bit, you get every combination in-between (all partial bits as well).

Can solve math problems that would take millions of years today in minutes. All calculations are performed at once!

Back to the Universe now…Back to the Universe now…

Remember the maximum amount of information you can transmit (contain in an area) is = to its entropy.

BUT Relativity and Quantum mechanics don’t get along (remember? Unless string theory is correct = unproven just promising)

Another example:Quantum Entanglement = “spooky action at a distance” = NO actual information transmitted!!

Most of reality (that fact that it is even stable) is due to entanglement of particles with each other.

Black Holes and InformationBlack Holes and Information

The most extreme! – Gravity becomes massive at the quantum scale.

The surface area of a black hole = k log W Entropy AND the maximum amount of information

you can pack into a space! And it lives on the surface NOT the volume!

The logical end of memory compacted-ness is a black hole.

It’s the ultimate memory stick! But can you get the information out?

Reading Black HolesReading Black Holes

Hawking Radiation– Virtual particles at the edge of the Event

Horizon– But can you get information out? Or is

information destroyed beyond the event horizon?

– S. Hawking thinks that yes, maybe. But no one knows how or for sure currently.

Gravity and EntropyGravity and Entropy

It can reverse it locally (as can the other attractive forces).

But this happens over time…But this happens over time…

So it’s time to talk about time…

Entropy and the Direction of Time

The Arrow of TimeThe Arrow of Time

Entropy seems to be responsible for the Direction of Time (the past is the past and the future is the future)

In Relativity and Quantum Mechanics, there is no preferred direction of time. You can reverse the sign of ‘t’ and the meaningful things still happen. Sometimes indistinguishable things (particles bouncing off one another)

S=k logWS=k logW

This means that the universe was very special at the start of time.

For us to still be running down (higher entropy) we had to be a universe of very LOW entropy at the start

How did the universe get ‘wound up’ or ordered at start?

One possibility…

The history of the

universe pt 1

The history of the

universe pt 2

The secret is a very very specific, low entropy, exact form of initial configuration of material/energy in the sub-atom sized nugget that started everything…

Back to parallel universesBack to parallel universes

So we can draw a bubble (like an event horizon) around us… say at the edge of the observable universe (our Hubble Bubble) and calculate how many states you can organize everything in (every particle in every spot).

Information and the UniverseInformation and the Universe

Information is located completely on the surface of a black hole (area = entropy = max information storage).

NOT the volume.Just like a hologram (3-D image in a 2-D

picture) (Remember the branes?)So all the information in the 3-D universe

can be encoded on a 2-D bubble.

So there is a distance from us So there is a distance from us where this exact arrangement where this exact arrangement

of particles repeats!of particles repeats!

10115

10 meters

Plenty of room for this in an infinite universe

The Other The Other You’s You’s

Implications of an infinite flat universe

The Matrix RevisitedThe Matrix Revisited

The universe ACTS like memory in a computer. With multiple bits at every point that are ‘empty’ space or a particle (or string with that vibrations for those phenomena) and rules that dictate how they communicate and interact – just like a computer program.

And there may be an infinite amount of memory for the universe and its version to be written on!

Quantum GravityQuantum GravityGravity (and all forces) are just communication

between “points” of space (smaller than the plank scale = 10-35m.

To be tested by a satellite looking at cosmic rays…quantum space time fabric = a smearing out of distant light. A smooth space time fabric = no smearing out.

And we’ll be looking for neutrinos from the big bang!

Other Further Readings:Other Further Readings: “A New Kind of Science” – Stephen Wolfram – All

reality is tiny simple programs running on sets of points of space/time. Similar to fractal mathematics. Complexity comes from simplicity. Cellular automata

Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions (2005) by Lisa Randall

The Fabric of the Cosmos: Space, Time, and the Texture of

Reality (2005) and The Elegant Universe (2004) by Brian Greene

A Brief History of Time (2005) and The Universe in a Nutshell (2001) by Stephen Hawking

There is much more being There is much more being discovered all the time… stay discovered all the time… stay

tuned!tuned!General Public Places for this information

(In order of easier to harder to read):

•Astronomy Magazine

•Sky and Telescope Magazine

•Scientific American

•Physics Today

•Nature and Science Magazines