What is important about the Big Bang And Black Holes topic?
I'd say it goes something like this...
1) "In the beginning..."
1.1) Singularity of infinitely small volume (and thus infinitely high temperature and pressure
1.2) This exploded/expanded - that event is the Big Bang itself
2) How do we know?
2.1) Hubble's Law - universe is expanding
2.1.1) Illustrated by Redshift [Light wavelength changes thanks to a stretching of the medium - space)
2.1.2) Extrapolate this backwards, and the universe would have been infinitely small at one point.
2.2) Cosmic background radiation
2.2.1) Remnants of the Big Bang explosion
2.2.2) Residual temperature in the universe of a few degrees Kelvin
2.2.3) Small temperature variations in this radiation - matter clumps; this clumping eventually aggregated itself into galaxies
3) What happened after the Big Bang?
3.1) Freeze-out of the "fundamental forces" - strong force, electromagnetic force, weak force, gravity [They used to be of equal strength, now they aren't - I just listed them in strongest-to-weakest order]
3.2) Inflationary Period
3.2.1) Especially rapid period of expansion in early universe (< 1 sec after BB)
3.2.2) Without it, the early universe would have had to have been relatively larg ein order to have reached the current size
3.2) Energy to Matter
3.2.1) E = M * C^2 : energy can be converted to matter...energy takes up less space than matter
3.2.2) Balance of matter annihilating antimatter, eventually regular matter won out
3.2.2.1) We don't know why regular matter won out
3.2.3) Big Bang Nucleosynthesis
3.2.3.1) Roughly 3min after BB. Occurred at temperature of 10^9 Kelvin
3.2.3.1) Particles coalesced into atoms
3.2.3.2) BBN only would have lasted long enough to form light elements.
Universe is made up of predominately light elements, this lending support to this important part of the Big Bang model
Various isotopes of hydrogen, helium, lithium and beryllium were formed
3.3) Later, stars and galaxies develop
4) The Cosmological Principle: important concept
4.1) Isotropic: Large-scale structure looks the same in all directions
4.2) Homogenous: General physical properties of the universe are the same everywhere in it
Thus, the universe has no edge and no center
5) What are galaxies?
5.1) The Formation of Galaxies
5.1.1) Galaxies formed about 1 billion years after big bang
5.1.2) Hierarchical merging [smaller-scale version of this process likely forms solar systems]
5.2) Different galaxy shapes
5.2.1) Spiral - a disk with spiral arms. Our own Milky Way is one. Relatively small nuclear bulge. Relatively large amounts of young stars and star formation.
5.2.2) Elliptical - Dominated by spheroid. Relatively old
5.2.3) Irregular and Peculiar - Those terms mean what you think they mean. :)
5.3) Galaxy relations: Galaxy clusters, superclusters
5.3.1) Galaxies do gather into clusters
5.3.2) Supercluster Types
5.3.2.1) Rich - >1000 galaxies, giant central galaxy
5.3.2.2) Poor - 10 to 1000 galaxies, more spirals
5.3.2.3) Isolated galaxies - even more likely to be spirals
5.3.2) Galaxies in superclusters not gravitationally bound to each other
6) What are black holes?
A superdense object, to the point where its gravity is so strong that not even electromagnetic radiation [light] can escape
6.1) Fuller explanation of black holes is provided by Einstein's theories of relativity
6.1.1) Spacetime - space and time are connected (they are *relative* to each other)
6.1.2) Gravity is dependent on spacetime
6.1.3) Special relativity predicts/explains unusual behavior that occurs with abnormal values of space, time, and/or gravity
6.2) Now, if no electromagnetic radiation, visible light or otherwise, emerges from a black hole, how do we study them?
6.2.1) Their effect on visible bodies near them: For ionstance, a black hole may suck in gas from nearby stars
6.3) Black holes are the Las Vegases of the universe - what happens [goes into] in a black hole stays in a black hole.
6.3.1) This is how black holes build mass
6.3.2) Difference: Actions in Las Vegas may also cause alimony, child support or prison time to increase
7) Dark Matter and Dark Energy: The Monkey Wrench in the Cosmological Works
We don't know what it is; hence the name 'dark'.
Nonbaryonic ("Baryons" are a type of particle with protons and neutrons being the most notable examples of them)
7.1) Composes most of the universe
7.2) Dark matter:
7.3) Dark energy: even more "weird" than dark matter
-More to come-
Showing posts with label BBBH. Show all posts
Showing posts with label BBBH. Show all posts
Thursday, May 8, 2008
Wednesday, April 2, 2008
E = mc^2
E = mc^2 actually refers to particles without motion, plus the energy of motion
With the energy of motion, you can have mass of 0, and still have energy
Applies to many different areas of the universe
E = mc^2: A recipe for converting matter to energy and vice versa - requires energy to make such a conversion, and a lot of energy
Energy doesn't take up much space, takes up more space when converted into matter
With the energy of motion, you can have mass of 0, and still have energy
Applies to many different areas of the universe
E = mc^2: A recipe for converting matter to energy and vice versa - requires energy to make such a conversion, and a lot of energy
Energy doesn't take up much space, takes up more space when converted into matter
(4/2/08) - From Big Bang to Black Holes
Most of what we know about the universe comes from our analysis of electromagnetic radiation (i.e. light)
Light is like a wave
Electronic wave and magnetic wave oscillate together
Black hole in center of galaxy = 1 million times the mass of the sun
The Sun = a basic unit of measurement
ergs = g*cm^2 / second^2
Solar luminosity = 3.8 * 10^33 ergs/s
Mass: 2 * 10^30 kg
Age of universe: 13.7 billion years
Speed of light = 3 * 10^8 m/s
parsec = 3.26 light years
Special Relativity
2 main components:
* The laws of physics ar ehte same in any inertial frame
* The speed of light is the same for all observers in an inertial frame
Spacetime is 4-dimensional
A frame in which unaccelerated objects move in straight lines is an inertial frame
A globally inertial frame is a frame that covers all spacetime
Addition of speeds
Walking 5 mph, Bus 30mph, difference 25mph
Rocket 100,000km/s, Light 300,000km/s
Difference appears differently because the observers involved see spacetime differently
Time dilation: the time lapse between 2 events changes from one observer to another; it is dependent on the relative speed of the observers
Lorentz contraction - the dimensions of an object as measured by one observer may be smaller than that of another observer
This also has implications for how gravity works
Newtonian gravity: F = G (m1 m2)/r^2
General Relativity: mass-energy causes spacetime to curve
Objects, including light, follow the shortest path in curved spacetime
Gravity = curvature of spacetime
Clocks more slowly the closer they are to a gravitational mass
Sun's gravity would bend light coming from background stars
Time slows near any massive body. Slows down even near Earth. [albeit in very small amounts - 4 parts in 10 billion]
The angular momentum of a rotating body drags space into a tornado-like whirl around it. (small whirl
Will see object differently if a mass is on the way. This is called a "gravitational lens".
When the gravitational lens is perfectly aligned with the background object, the background object is modified into an Einstein Ring
Black holes - so much mass in such a small space that the spacetime warp is extreme
Nothing can escape, not even light
Detect black holes by their gravitational effect on nearby object
Stars, specially those near Galactic Center, are detected orbiting it
Supermassive black holes probably exist at the centers of most galaxies
Called galactic nuclei
Could have come about or become larger during galactic mergers
Collision of two black holes is the most violent event in the universe
* Produces wild vibrations of warped spacetime
Black holes related to their host galaxies: "chicken & egg" problem
* galaxy formation far enough back in time that we can't really tell
* Hypothesis: growing together
What happens in a black hole, stays on a black hole. This is how black holes build mass.
Light is like a wave
Electronic wave and magnetic wave oscillate together
Black hole in center of galaxy = 1 million times the mass of the sun
The Sun = a basic unit of measurement
ergs = g*cm^2 / second^2
Solar luminosity = 3.8 * 10^33 ergs/s
Mass: 2 * 10^30 kg
Age of universe: 13.7 billion years
Speed of light = 3 * 10^8 m/s
parsec = 3.26 light years
Special Relativity
2 main components:
* The laws of physics ar ehte same in any inertial frame
* The speed of light is the same for all observers in an inertial frame
Spacetime is 4-dimensional
A frame in which unaccelerated objects move in straight lines is an inertial frame
A globally inertial frame is a frame that covers all spacetime
Addition of speeds
Walking 5 mph, Bus 30mph, difference 25mph
Rocket 100,000km/s, Light 300,000km/s
Difference appears differently because the observers involved see spacetime differently
Time dilation: the time lapse between 2 events changes from one observer to another; it is dependent on the relative speed of the observers
Lorentz contraction - the dimensions of an object as measured by one observer may be smaller than that of another observer
This also has implications for how gravity works
Newtonian gravity: F = G (m1 m2)/r^2
General Relativity: mass-energy causes spacetime to curve
Objects, including light, follow the shortest path in curved spacetime
Gravity = curvature of spacetime
Clocks more slowly the closer they are to a gravitational mass
Sun's gravity would bend light coming from background stars
Time slows near any massive body. Slows down even near Earth. [albeit in very small amounts - 4 parts in 10 billion]
The angular momentum of a rotating body drags space into a tornado-like whirl around it. (small whirl
Will see object differently if a mass is on the way. This is called a "gravitational lens".
When the gravitational lens is perfectly aligned with the background object, the background object is modified into an Einstein Ring
Black holes - so much mass in such a small space that the spacetime warp is extreme
Nothing can escape, not even light
Detect black holes by their gravitational effect on nearby object
Stars, specially those near Galactic Center, are detected orbiting it
Supermassive black holes probably exist at the centers of most galaxies
Called galactic nuclei
Could have come about or become larger during galactic mergers
Collision of two black holes is the most violent event in the universe
* Produces wild vibrations of warped spacetime
Black holes related to their host galaxies: "chicken & egg" problem
* galaxy formation far enough back in time that we can't really tell
* Hypothesis: growing together
What happens in a black hole, stays on a black hole. This is how black holes build mass.
Monday, March 31, 2008
(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.
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.
Friday, March 28, 2008
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
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
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