(3/31/08) From Big Bang to Black Holes: Part II

The Big Bang
The Evolution of the Universe
Galaxy Formation and Evolution
Dark Matter/Dark Energy
The Big Questions
Future Prospects

--
-Basic Forces-

Strong nuclear force - Holds nuclei together: Strength 1, Range 10^-15 m, gluons + nucleons
Electromagnetic Force - Strength 1/137, Range Infinite, photon [mass o] [ spin 1]
Weak - Strength 10^-6, range 10^-18m [0.1% of the diameter of a proton], intermediate vector bosons, W+, W-, Z0,mass > 80 GeV, spin =1
Gravity - Strength 6 * 10^-39, Range Infinite, [potential gravitron particle], mass =0, spin = 2

Cosmological principle - isotropic [large-scale structure looks the same in all directions] and homogenous [general physical properties are the same everywhere]

The universe has no edge and no center

-Hubble Law-
On large scales, galaxies are moving apart, with velocity proportional to distance

There is no center of expansion
Spacetime itself is expanding and carrying the galaxies with it

^ Can tell this via cosmological redshift


Redshift = (wavelength - original wavelngth) / (original wavelength)


Extrapolating backwards w/ Hubble's Law = universe had a beginning [infinitely small and hot] - the cosmic singularity

(Planck's constant t = 1.35*(10^-43) sec

--
We should expect thermal radiation from hot gas
Radiation should is blackbody spectrum

Initially, all four forces were equally strong.
Broke off in the following order: gravity, strong force, weak force
Gravity broke off (forze out) within 1 Planck time of Big Bang

First Galaxies - Approx. 1billion years after Big Bang

Bizarre inflationary period - exponential expansion of universe soon after Big Bang

W/O inflationary period, universe would have had to start out relatively large

Infationary period theory - explains lack of magnetic monopoles, horizon problem, flatness problem

Horizon problem: things far enough apart that they didn't come into contact with each other
Flatness problem: near critical energy density (eqiuilibrium point between infinite expansion and infinite compression) - Sphere needed to move from a small size (high arc) to large size (low arc) quickly

Initially, was equilibrium between pair production and annihilation (between regular matter and antimatter). There was a slight shift in favor of regular matter

Then, atomic nuclei were created (a few seconds after the Big Bang). This settled out a few minutes after the Big Bang.

This initial process created hydrogen, helium, lithium and beryllium (along with hydrogen isotope deuterium). Mostly hydrogen/helium.
Other elements were formed via fusion in the center of stars.

As universe expanded, it cooled down, cooled down to a point where atoms formed, and electrons were not allowed to interfere with photons anymore, because they were locked down in atoms

Cosmic Background Radiation was predicted as a 'signature' of the Big Bang.
R. Wilson and A. Penzias won the Nobel Prize for discovering this in 1978


Highly isotropic - intensity of this radiation very similar in all directions
Perfect blackbody spectrum would have a temperature of 2.725 Kelvin

Slight nonuniformity explains the clusters of matter that ended up as galaxies


Spiral galaxies: relatively small nuclear bulge, disk with spiral arms, gas/dust/star formation/young stars
Barred spirals are 2/3 of all spirals; they have elongated nuclei with spiral arms emerging from the ends

Elliptical galaxies: squashed-sphere shape, largely old stars

---
Even seemingly empty patches of sky probably contain very distant, faint galaxies
Most galaxies are members of clusters; galaxy clusters themselves are grouped into superclusters [many superclusters have a few dozen clusters spread out over ~40 Mpc]
Superclusters are *not* gravitationally bound

Rich Clusters - >1000 galaxies, ~ 3Mpc diameter, condensed around a giant central galaxy
Poor Clusters - 10-1000 galaxies, more spirals
Isolated galaxies are mostly spirals

Hierarchichal merging - start of cloud og gas, which starts telling out and clumping into discrete entities.
Galaxies were formed this way, and probably solar systems aswell

Star birth comes about relatively early in the universe (0.5 - 1.0 billion years ago)

Dark Energy - 70% of universe
Dark Matter - 25% of universe
Free H, He - 4%
Stars - .5%
Neutrinos - .3%
Heavy Elements - .03%

By the way gravity is behaving, we know there has to be a certain amount of mass, not all of which is visible matter - hence, dark matter

Is dark matter baryonicor nonbaryonic? Most probably nonbaryonic

Gravity should slow down expansion, dark energy should speed up expansion

Current data pointing to expansionary model; we're not sure.

Topic Summaries

Topic summaries are a major part of this class' assignment mix.
They consist, of, well, a summary of each topic the class covered. (There are four separate documents involved; one for each of the four topics)

We're given latitude in what format to use.

Common is the old standby; PowerPoint (However, this has to be done well; not just simple bulleted text and the like)

Our classroom has some special equipment that can be summed up as a 'immersive environment'. A large part of this is a wide special screen, which actually seems to consist of four panels. Easier to see, and with the capability of displaying more information at a time. One of the things it can do is display four slides' worth of information at a time, and I am using for my topic summary a Power Point template designed to work with this feature.

Tags

Tags

The Frontiers of Science class covers 4 topics: Viruses, NanoPower, Vision and the Mind, and Big Bang/Black Holes

Blogger's tag system is an excellent way to sort out which posts go with which topics:

http://alan-labbook.blogspot.com/search/label/Viruses
http://alan-labbook.blogspot.com/search/label/NanoPower
http://alan-labbook.blogspot.com/search/label/VisionAndMind
http://alan-labbook.blogspot.com/search/label/BBBH

http://alan-labbook.blogspot.com/search/label/Administrative
http://alan-labbook.blogspot.com/search/label/General

Brain sections:

Frontal lobe: infront
Parietal lobe: behind the frontal lobe
Temporal lobe: bottom (has to do with the word 'temple', not 'time')
Occipital lobe: at the back and underside; the vision center

Temporal lobe: wraps around amyglada and hippocampus
Corpus collosum: a collection of wires that helps integration of left and right hemishperes

Occipital lobe "breaks down" into area that handle different visual functions

V1= Striped cortex = primary visual cortex = Area 17
A progression from V1 to V2, etc; but some signals skip a few laters

The five basic senses "hub" in the parietal lobe

Olfactory bulb: brain component in front center of brain, goes right to center of brain on its own sensory pathway

flavor = taste + smell

-Structure of a nerve cell-
Soma (neuron cell body) sprouting dendrites that connect to other nerve cells: 5000-10000 conenctions

Axon inside myelin sheath (myelin sheath is white; hence 'white matter'); signal travels down that axon to 'terminal buttons', the 'terminal buttons' conencting to other neurons

Small voltagde differences (70 millivolts) accumulate across the dendrites. Huge depolarization causes a neuroncharge to fire
Elctrodes can be placed directly in brain; but it's a last-ditch process.

Electrodes outisde/on the skin a different story

epileptic focus often in parietal-temporal-occipetal junction

Electrode cap - 20 electrodes: A1 and A2 (on the ears are a reference point compared to the brain activity at other points

EEG's produce a waveform patter that's different depending on the activity in question, and whether part(s) of the brian are damaged

EEGs look over seconds' worth of data
fMRI's look over minutes' worth of data

ERPs - event-related-potential [EEG-measured stimulus response

Sigt experiments: measuring responses to being told to look through certian things. Can sput a certian feature within milliseconds.

80-100ms for signal to go from eye to visual cortex

CAT scan - digitized X-ray

MRI studies brain anatomy - an MRI system would image whatever's put in
fMRIs study brain function

The whopping strength of the MRI magnet makes safety essential. Things fly - even big things. :)
Similar visual equipment in other hemishpere

Actual gray matter is 2 millimeters thick, 6 layers, 1 at outside, 6 at bottom. 3 and 4 are I/O layers, others focus on internal processing


up/down and left/right are reversed in the brain.

Vision and the Mind

* Imaging Science / Psychology crossover

* Professor Pelz: The role of eye movement - active vision

* "Optical illusions" really "neural illusions"

* Some illusions easy to explain; some aren't

* Very young children see some of these illusions differently; older people have visual experience

* After 20-second video of spiral, you see the spiral's movement pattern even after it's turned off. So, even for a short timeframe, your eye was 'trained' to that movement.

"Rods" and "cones" light0sensitive things in back of retina named for their shapes

"Bipolar cells" feed signal into "ganglion cells", which in turn send the signal to the optic nerve.

Light actually flows through the ganglion and bipolar cells, hits the rods and cones, and then bounces back

Photon absorbed by rod or cone; voltage induced; signal gets changed at the synapse (lateral inhibition: one full-strength positione charge, two half-strength negative charges

Sometimes neurotransmitters are struck by multiple such charges
.

If the input field is 100% uniform, the charges would entirely cancel each other out. However, at edges of objects, the strength of incoming light is different, so only the edges of the visualized object are accentuated.
This is a data-compression scheme; computer image-compression algorithms actually do something similar.

Your visual system

Herman's Grid - black squares, thick white gridlines
Criak-Obrien/Cornsweet illusion - rectangle that appears to have dark gray left half and light gray right half; really a uniform color

Fourier transform: math algorithm that looks for "just the edges"

Blurry image: has no clear edges

Snakes illusion- apparent motion when going from the spiral pattern to a blank surface.

When surface is darker, your optic system integrates the images slower, so you'll see elss flicker on a darker screen

Vertical angle * horizontal angle = degrees-squared on the field of vision

Visual system focuses on detecting motion

Field-of-view vs. acuity compromise

Cones: High acuity [and color vision]
Rods: Low acuity and high sensitivity

If you hold a finger out at arm's length, the fingernail is about 1 degree wide.

There is a blind spot at a certain degree of the field that comes form the space where the optic nerve comes back out

Small blind spot aswell form the following: No rods directly ahead (0 degrees); only cones in that area

little depression at the center of your retina

Limiting acuity in the periphery is a part of the compromise; but need to move the eye around so that the strong-acuity area can cover different parts of the world

Ocular motor system: six muscles in three pairs (one does left-right, one pair does up-down, and one does rotation)

How much info is enough?
How quick is "just in time"?

saccades = rapid movement of eyes to look at a new object or region

Smooth Pursiut: stabilizes view of a moving object

Tremor, drift and microsaccades when you try to hold your eye steady

optokinetic response / optokinetic nystagmus

Have to serialize your visual-information intake
That presents problem of temporal-integration

Various devices to track eye movement in the laboratory
* Measuring reflection off the eye, in some way, is a common method

* Wearable eye tracker is the next development goal; starting to have success on that

(3/21/08)

Electrolysis: Put 2 metal rods into a beaker and run current through. You will see bubbling on each. One is all-hydrogen, one is all-oxygen. Would come up with soem ort of metod to trap the respective gases.

Need atleast 1.3 volts of current for electrolysis to work

Example solar panels he showed: 3 panels, each with a 2-row, 5-per-row arrangement

pn junction = diode = current can flow in 2 ways.

Electrons moving through a pn junction = sledding-hill analogy

Electrons slide down the hill (go between either end of the gap), releasing energy. Need energy to get pack up and redo the process; this energy is provided by photovoltaic energy striking the solar cell

Stack a whole bunch of fuel cells in series, then put some fuel-cell-banks in paralell, since each individual cell provides
----
Regular electricity:
Hook up batteries or solar cells in paralell - no voltage increase, but a current increase
Hook up batteries or cells in series: no current increase, but a voltage increase

power = voltage * current

Voltage - kind of like how high you put your water tower (how much pressure)
Current - kind of like water flowing through a pipe (how much flow)

Different electric applications require primarily one or the other

10^19 charges = coulomb
1 coulomb per second = 1 amp
----
Solar cells expensive; pay back over the course of relatively few years
PROVIDED, that local municipality supports "net metering", where your electricity meter runs backward when your solar array pumps power into the grid; this makes the payoff time quicker

Utilities don't want this cutting into their business

Big Oil funding solar research; they want to get in on the "next big thing"

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How does NanoPower relate to space colonization?
* Most of our stuff is low-orbit, so that's what we focus on; so even when we go out of low-Earth orbit, we use similar equipment.
* Air-generation systems would be very important to longterm space exploration; a problem we're more worried about than power generation
----
Radioisotope problem: A lot of energy, but we have to work on the terms of that radioisotope's half-life.
Spontaneously emits; no need to trigger it.

Only way to improve current is to have more mass
Need to produce many of these radioisotopes in a reactor

May still be useful at the lower current-rates of the second half-life
Decay in a regular pattern, so we can design accordingly.
---
Nanotubes: Some are metallic (normally conductive); some are semiconductors (unless you dope them, or shine light on them, often aren;t incredibly conductive.)
If we could make a batch of exactly identical nanotubes; we'd reach the Holy Grail of nanotech.
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Steam reforming: pump steam through a fossil fuel; liberates the hydrogen, with CO2 as the byproduct.
However, the CO2 is trapped and used for industrial processes rather than pumped into the air
---
How are solar cells produced?
Different method:

polymer, silicon, 3 5 (3rd +5th column of periodic table, like gallium arsenide)
--
silicon-type: a bunch of boron atoms on surface of silicion; put that into a furnace; this speeds up the diffusion of the other half of the pn junction; so it "bakes in" the pn junction.
--
polymer-type: paint a negative polymer and a positive polymer on in alternating layers


NanoPower's advantage comes in making these other technologies more efficient and cheaper
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Ethical debates with nanomaterials: toxicity concerns are the big one
--
Aren't nanotubes expensive b/c they're a new technology
Some types are, some types aren't (You can use laser vaporization, or you can burn stuff). It depends on what quality you need for the application in question.
--
Problem: waste with drained batteries that need to be disposed of. This is a real problem.
Lots of military equipment that goes through batteries like crazy, for instance.

Are flammable materials in batteries, but you could be aerosoling dangerous chemicals that were in the battery.

quantum dot = nano-scale piece of a semiconducting material. Rule sof macroscopic materials no longer really explain what going on; so we have to use quantum mechanics

any way you burn carbon, you can make nanotubes.
Are made naturally with natural combustion of carbon, but we simply didn't know about them before

Nanotubes are almost to the scale of quantum mechanics

quantum confinement, how materials behave on those really small scales, is really important to nanotechnology

Laser vaporization: fire laser at graphite target with some metal.

Result is purified - boiling in acid (handles metal), burning (deals with soft carbon)


Electrical conductivity resistance of carbon nanotubes does not increase with temperature, whereas resistance of regular metals does

(3/19/08) NanoPower lecture

Reminder:
Specific Power: power per each unit of mass

Radioisotope batteries: Long-term, but a small amount of current (have to wait for the half-life)
If you go for a short, quicker half-life, the battery doesn't last as long.

PMAD = Power Management and Distribution

Starshine: Looks like disco ball; used to monitor near-Earth-orbit drag
Solar activity is related to this drag; solar wind particles (sort of), but also

Nickel-metal-hydride batteries: Heavy (not the best specific power or energy density), but easily rechargeable

Lithium-ion: Better specific-power and energy density, but not as rechargeable
Lithium-ion batteries used in Earth-based electronics; so there's more R&D going on

Hydrogen fuel cells like batteries in design, but instead of passing ions back and forth, new ions (fuel) are pumped in.

Now how can nonomaterials help us with all of these power tasks?
Carbon nanotubes are used to improve performance

Inadvertent uses of nanotechnology exist farther back in history - Lycurgus cup comes to mind

buckminsterfullerenes discovered in 1980s: New ball-like form of carbon

Rolling up a sheet of paper = analogous to nanotubes. Can roll up the paper in different ways, and as such, can make different nanotubes. Some are metallic; some have varying degress of conductivity

Typically about a nanometer in diameter; can be hundreds or thousands of microns long; thus an unbelievably high aspect ratio.
Also a very-good thermal conductor
Strongest material known to man under tensile force

Solid-state physics law - Veidelman and Franz
* examined various conductors (gold, lead, etc)
* Ratio of thermal conductivity to electrical conductivity was the same for various materials
* SOme materials do violate this law, nanotubes aren't one of those.

Binding polymers used in actual battery applications, to keep the carbon-nanotube powder from getting all over the place.
Need at least 30% graphite to have conductivity
Need only one or two percent nano

Kind of like crossing a creek (creating a conductive path): Either pile rocks in, or lay one log across

Stronger, smoother plastic when nanotubes are used
Nanotube usage would speed-up the charge rate

Nanotubes group via van der waals effect.
Can make multi-wall nanotubes: easier to produce

(lecture 3/17/2008) - NanoPower introduction

Nanopower is power in space.

You can get this in two ways:
1 - Take fuel with you
2 - Scavenge (Scavenging includes solar power, and mining extraterrestrial environments)

When using solar, have batteries for when your craft isn't directly in the sun

Fuel cells were used on Apollo missions - they created electricity and water

Nuclear reactors can be used in space - a lot of power in a small weight; a lot of energy emitted in radioactive decay particles
Take forever to decay;so a long-life battery

Solar arrays - a lot of them are heavy,fragile silicon
90 % of current solar cells are silicon

SOlar cells only 30% efficient; you need heat dispersion

Chandra - X-ray observatory - X-ray astronomy can only be performed in space (too many X-rays get interfered with by Earth's atmosphere)

Mirror assembly had to be aligned with exacting precision.

Space SOlar Power
1) Convert solar photons into electricity
2) Efficiency
3) Mass Specific Power (power/mass)
4) Areal Specific Power (power/area)

Solar wind, v. small amount of drag, UV rays,micrometeoroids, space debris still a problem

Heavy glass currently necessary to shield solar cells
Anti-reflection coating

n-type semiconductor and p-type semiconductor - one has extra electrons, one has a deficiency of electrions.
pn junction - these two together; electrons bounce between them (that's the photovoltaic effect).
You need enough energy to kick the electron(s) between the levels.

SOme wavelengths have too much energy for this (that wastes heat).Some wavelengths have too little (not do enough). Some are just right [ Goldilocks Principle]

Concentrators concentrate the light,but they heat up the solar cell assembly. Generally aren't used
Space-power people very conservative

MOCVD
Metal organic chemical vapor deposition

OMVPE


How the semiconductors used in electronics are grown

If you drive electricity into a solar cell or other semiconductor thingies, you get light.
This is the basis for LASERs and LEDs.

If you connect batteries in series, the voltage adds, but the current is the same.

Small increases in efficicienty, even fractions of a percent, are a huge deal.

When semiconductor reduced to the nano-scale, its band gap changes based on the size.
Gets into quantum mechanics

Questions

1 - Inadverntent Vaccination

Vaccines that are modified viruses - problem of *those* being transmitted

* Depends on characteristics of the specific modified virus
* Some people will be more-vulnerable to even a weakened modified virus
* Can address this by heavily customizing the modified virus

2 - VSV and interferon

Why isn't interferon beign released form VSV-infected cells?
Does this have anything to do with interferon.

Either VSV isn't inducing interferon, or it;s stopping interferon that is getting released.

3 - What if the vaccination causes a disease?

* The question addressed by Phase I clinical trials (giving vaccine to previously-healthy people)

* The question of pharmacology: the risk/reward analysis

4 - Sanitation

* If over-sanitation is increasing susceptibilty to some diseases, should we consciously tone it down?

Yes.
Well, not in a hospital environment
* Natural flora - body has loads of "good" bacteria and viruses in it at any one time.
Don't want to kill those.

Gene Therapy and Viral Vectors

Gene Therapy: putting genes into the body's relevant cells to replace a screwed-up gene and thus fix a genetic disease.

Viruses can be used as delivery vectors for this.
(not the only vector: gene guns, injections, etc.)

Idea: apply gene therapy to fetuses (fewer cells to treat)

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Viruses and cancer

Oncolytic Viruses
"onco"- cancer
"lytic" - killing

Virotherapy: a therapy that seeks to harness the natural properties of viruses to aid in the fight against cancer

Strategies:
Viruses modified so as to only bind to cancer cells. (Finding the 'markers' is difficult)
Viruses "armed" with different/more genes to enhance effect
Viruses modified so that they can only reproduce in abnormal cells

Great idea in theory; how will it work out in process.

Also, tumor cells tend to lack proper interferon response.
--------
Advantages of VSV in particular come into play
--------

Political problems a danger to worldwide disease-eradication campaigns
Vaccination campaigns always harder in developing countries anyways.

W/ polio, virus changes a bit

(3/12/08 lecture): Viruses as friends

Knowledge of cellular mechanisms
Foundation of molecular biology
Technical development
Knowledge of disease

-Vaccines-
* Some made from weakened versions of the target virus
* Some made form another virus

Vaccine trials = need a lot of $

(3/12/08 lecture): More about viruses

Vuris mess with the DNA-RNA-protein model that is a major tenet of biology
----
Different viruses progress differently after they infect you - graphs on the way

Consequences of viral infections:

* Some are fatal
* Some related to congenital diseases

* Contributory factor to cancer (like HPV --> cervical cancer)
* COntribute to other diseases


* Economic impact
---------
*Some viruses asymptomatic - not all viruses make you sick
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Pathogenesis: *how* viruses cause disease

Eyes, mouth, skin [abrasion, injection], respiratory tract, alimentary canal, urogenital tract, anus

^ Different viruses target different areas

Attachment: Some viruses work with a cell receptor unique to a specific type of cell.
Once attached, virus gets thorugh the cell membrane and inside the cell

The few genes/proteins in a virus genome aren't enough to do what it needs to do, so it gets that by hijacking the host cell.

----
Vesicular Stomatitis Virus
Preferred host: cattle
Can target other organisms if the virus is in a larger concentration

Can kill a cow in about a week

Only has 5 proteins

RNA degrades pretty quickly in the open environment, N-protein of VSV guards it.

Can easily add a 'tracking' gene (i.e. staining/coloration)

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Virus invasion of a cell triggers the cell to produce "interferon" (cellular distress call)
Some viruses interfere with interferon

What prevented pilio's eradication in 2000?

What prevented polio's eradication in 2000?
First, it is important to note that a lot of progress *was* mad ein polio reduction, confining it to just some areas of the Third World by 2000.
This means:
A.) Society was on the right track
B.) Logistical problems having to do with the Third World might have stood in the way

It's not like anti-polio workers "packed up and went home" after the 2000 deadline, so a pattern of progress continues.

Global goal to eradicate polio was set in 1988, 11 years *after* the declared eradication of smallpox. So,logically, a project of this scope would take a while.

"by the end of 2006, only four countries remained which had never interrupted endemic transmission of wild poliovirus (Nigeria, India, Pakistan and Afghanistan)"
This goes back to the Third-World logistical issues above, and Afghanistan has been ravaged by war and civil strife for decades.

Viruses: Friend or Foe (3/10/2008 lecture)

Today - focus on traditional bad viruses
Wednesday - more-positive uses of viruses
Long bad history

Egypt - withered legs (from polio?), smallpox lesions
Homer (the old Greek one, not the Simpsons one) discussed rabid dogs

Viruses have reshaped human history
Smallpox - major tactical advantage Europeans had vs. Native Americans
Influenza - post-WWI not the only major epidemic
Polio
HIV

-Role of biological warfare-

Smallpox - very contagious - psutiles of smallpox victims burst to spread lots more of the virus
Smallpox - only infects humans
Declared eradication in 1977

Influenza - smaller particles than smallpox virus
Influenza epidemics - a lot of them, but post-WWI was the worst - 20,000,000 dead (double WWI combat deaths)
1920 epidemic hit mostly the very young and very old, but also deaths inbetween,hich was shocking

Polio - FDR's suffering form the disease galvanized response
Polio often causes paralysis. Iron lung necessary if diaphragm suffers from the paralysis

Polio epidemic in 1952 - side-effect of cleaner society (less mild immunities built up)

HIV-AIDs - Misunderstood in the beginning, misunderstanding-based public fears
Africa being hit especially hard

Polio elimination followed smallpox. Polio endemic area reduced to India and parts of Africa

Chicken v. Egg - viruses or bacteria?
Were virus-like things the first replicators? Modern virii need cells to replicate, did the ancient
ones?

Okay, some bad things that viruses have done.
Now what are they?

They are very very small (20-400 nanometers)
DNA or RNA in genome
Protein shell
Some, such as HIV, have a lipid (fat) envelope
*obligate intracellular parasites*

Different viruses can affect all different types of organisms (any of the other phyla)
Filterable if you can do a filter small enough

What is this?

This is a blog I'm using as the repository for notes and other related class materials for one of my RIT classes, called 'Frontiers of Science'

I have a laptop out during class; generally typing my notes directly into Blogger's 'new post' form. [Thank you for automatically saving my drafts. :)]