ILEU

Defs

Cluster/group of galaxies

structure that consists of numerous galaxies bound together by gravity

Supercluster

cluster of galaxies forming a cluster

Galaxy

massive, gravitationally bound system consisting of stars, stellar remnants, an interstellar medium of gas and dust, and dark matter

Stars

large, self-luminous astronomical bodies

Planets

Subtopic

Local Supercluster

The Virgo Supercluster or Local Supercluster is the irregular supercluster that contains the Virgo Cluster in addition to the Local Group, which in turn contains the Milky Way and Andromeda galaxies.

Habitable Zone

region around a star within which planetary-mass objects with sufficientatmospheric pressure can support liquid water at their surfaces

far but close enough for perfect temp

4.56 billion years old

Early formation of crust - Zircon found 4.4b yrs old

ecliptic orbit around sun

Mars

Nomad/Terrestrial Planets

Venus rotates on axis opp to others

Jovian Planets

Uranus tilts axis at sun

Life of Stars

cloud of gas collapses due to weight

causes spin to increase, dense object forms at core, heats the gas

once density & temp high enough, thermonuclear burning/ fusion starts

made of H and He, and heavier element contaminants (from other supernovae)

classification of stars

Hertzsprung-Russell diagram (luminosity against temp)

Evolution

gas cloud collapses
Burns H in core
Later burns H in outer shells
Eventually removes outer shells as planetary nebula
forms white dwarf

Planetary Nebula: illuminated gas cluds
White Dwarf: hot ember of degenerate matter cools w/ time

DEATH

Neutron Stars

observed as pulsars

(highly magnetized, rotating (~1 sec on axes) neutron star that emits a beam of electromagnetic radiation.)

at ~6bill yrs, star starts to change
all H in core to He, core collapses, moves further out of star, less gravity, star expands

surface from 6000 to 3000K

Depends on star's mass

>10 solar masses (1.99x10^30kg)

burn all H, up to Fe
final collapse and burning is fast & intense
star becomes super heavy core
remaining gas released as supernova

Core becomes:
Neutron star
Black hole (if original star heavier)

fusion process stops, no more fuel (H hot and dense enough to fuse)

fusion is halted since iron is so tightly bound that no energy can be extracted by fusion. Iron can fuse, but it absorbs energy in the process and the core temperature drops.

End of Star

outer layer blown away by solar winds, core becomes hot ember- white dwarf, black when no more energy

products of fusion - depends how massive as to what elements e.g. larger stars can continue to fuse C after He used up, or He if especially large and after C used up

Forming stars-
* Slow collapse at first, non linear collapse
* Reaches point at which it speeds up
* Generation of stars before the solar system we now know, to have heavy elements we observe
* Gas clouds lose potential to kinetic, as it collapses it speeds up due to angular momentum
* Fusion releases energy and powers sun
* Supernova can be extremely bright
* All elements we see in everyday life from supernova

initially smooth distribution of dark and baryonic

over-dense = collapse under gravity

formed 4.6 bill years ago

formation of planets

nebula hypothesis

large gas cloud collapses non-linearly, spins faster as it condenses

planetesimals form, attract one another and form planets, heavier elements fall towards center, creating core

Marine life, nothing would have survived above (too much UV- Sterilise)

Stromatolites

cyanobacteria, stopped occurring ~500Ma ago

changed dynamics of atmosphere

CO2 removed

life begins to move to land, increase in size

life coincides w/ O2 increase

anoxic, disoxic, oxic

O2 disappears w/ oxidation

* marine life have cal carb shells, goes to bottom of ocean and turns to limestone



*
* carbon underground also maintains
* 21% o2 now


* Timeline (slides)

Necessary/Must vs. Sufficient/ Enough to produce life

* Fossil preservation- ice, tar pits, mummification, mud, water, bogs can pickle, amber (fossilised tree sap),
* Any way that stops decomposition
* Predation, erosion, transportation

can stop fossilisation

* After earthquake, gas on bottom rises out, asphyxiates life that flies over, it falls in and may be fossilised
* Fossils include traces, not just bones, fur, tree trunks
* Coprolites- fossilised dung
* Jellyfish preservation- falls in mud, makes hollow, have sand or something not mud on top, decomposes and leaves impression


Cntd.

* No shells to small smalls to many

* To protect environment inside from out
* Spike in O2 around 540 Ma ago
* Predator prey relationship

* Cambrian explosion- Burgess Shale- know time scale!

* Preserved sea bed
* As carbon film
* Pikaia- invertebrate, chordate- one of our ancestors
* Catastrophic event buried these things quickly (soft bodied) submarine avalanche
* Evolved to fill niche, specialisations die out if can't adapt
* Diversification

* Early life David a


Palaeozoic

* Life went to surface from ocean
* Know eons!!
* Lobe finned fish evolved legs
* No flowers in eon- ~1Ma
* Carbon iferous

Kepler Satellite

measures brightness of star periodically

revolutionised no. of planets found

most planets are: Neptune>x> Earth

UNITS

Lecture 5

* two prim. processes to form elements- early universe, photons form mostly H

* cores of stars at high density and pressure

* b4 10^-43 seconds, physics breaks down- can't define where universe is
* Heisenberg uncertainty principle
* 300k years, charged becomes neutral- almost all uniform
* 3 mins= two body reactions w/ protons & neutrons 4 He
* beginning of universe
* nucleosynthesis
* isotopes of H
* energy released most favourable-as mass turns to energy E=mc^2
* anything above iron diff process- requires supernova
* cosmic ray interactions- Le,Be, B
* two processes happen in stars
* why Fe so stable (lowest binding energy per nucleon)- For an iron nucleus to undergo fission or fusion it has to absorb energy, so the odds are against it doing either of these things.

(Rather than releasing energy)

* live in atypical part of universe- too many heavy elements
* Binding energy- why Ni & Fe found in cores of planets- left over products from supernova
* stars- explode as supernova or form black hole if massive enough
* enriched clouds- gas and dust full of S and Fe b/c can't see through them
* gas cloud large enough- collapses and spins faster- hot core forms at centre- heavy elements move to center
* accretion process- growth or increase by the gradual accumulation of additional layers or matter
* solar winds from sun- clear out gas and dust left over


Lecture 6

* Sun has diff trajectory at diff times of year
* Process is ubiquitous
* Be able to explain angular momentum about planets
* Disk heats up, must cool
* Planetesimals
* Heavier elements flow towards center
* Cool enough attracts lighter elements gas
* Too hot too much kinetic energy and not attracted
* Solar wind
* Zodiacal
* Icy junk- comet


1. Left over from formation of planets like Jupiter, Saturn, tail when hot enough- see it melting
2. Finite number of times, melts a bit more each orbit
3. Two tails- one tells direction in which comet came, other is ion (plasma)- tells where sun is


* Rocky junk- asteroid- belt bw Mars & Jupiter
* Oort cloud- cold storage of comets
* Kuiper belt
* This junk helps explain how solar system formed
* Mars' moons asteroids that were captured into orbit
* Symmetric bulge of earth- bulge passes over every 12 hours, can see through high tide
* Intertidal regions huge back at formation of moon
* Why moon only faces earth one way
* What switches stars on
* 4.7 bill years ago, sun formed from supernova nearby


Solar system planets

* Watery surface crucial for life development
* Silicates in abundance
* Mercury atoms escape from surface
* Doesn't rotate in axis very much,one side typically faces sun
* Venus- primary source of atmosphere from volcanic action like Earth
* Remained same since then, Earth became diff
* 70xpressure
* Primordial atmosphere- mostly co2
* H2o evaporated, light from sun broken ,molecules into H, which then escaped, o2 bonds w/other atoms
* Mars-one mostly h2o, other icecap co2
* Jovian planets
* No solid surface
* Hard to define atmosphere
* NASA websites good about planets
* Red circle is never ending storm on Jupiter
* Rings are hundreds kms across, 20 m thick
* Not so high density, satellites passing are okay
* What elements in planets, why we see them as certain colours
* Temp measures size of velocity of molecules
* All atoms equalize to have same kinetic energy
* Hence light atoms like H have high energy, more velocity, easier to escape!
* If gravity still high at coolest part, lighter elements and molecules will stay
* No H in Earth's atmosphere
* Why does hotter planet have co2,but moon doesn't
* Why don't atoms from other processes leave?
* Plasma and dust tail
* Meteorites may evaporate on impact
* K/t bad bc of dust it'll out into atmosphere,will stay for years,ranging that depends on sunlight will stop

Regions that lie between normal faults and are either higher or lower than the area beyond the faults.

A horst represents a block pushed upward by the faulting, and a graben is a block that has dropped due to the faulting.

Formed when normal fault of opposite dip occur in pair with parallel strike lines - always formed together .

Glaciation

2-3 major ones in past

random boulders on landscape due to: landslide, meteorites, volcano eruption

Tectonics

PROOF
- Continental fitting
- Similar fossils in diff continents
- Large amount of seismic, volcanic, and geothermal activity along the conjectured plate boundaries
- Ridges where plates are separating that are produced by lava welling up from between the plates as they pull apart. AND mountain ranges being formed where plates are pushing against each other (e.g., the Himalayas, which are still growing)
- Hot spots and consequent volcanoes moving away
- Records in magnetic minerals

Rocks

Types

Igneous

bluestone, granite

Formed through the cooling and solidification of magma or lava. May/ may not have crystallization

Metamorphic

The original rock is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (1500 bars)

Mix of sedimentary, igneous or older metamorphic

Sedimentary

source of gas and oil, fracked, water

Formed by deposition of material at the Earth's surface and within bodies of water.

Tillite

part of glacial drift which was deposited directly by the glacier.

Evidence of snowball Earth

Natural glass formed by melting to molten and then cooling extremely fast- unstable, w/ air pockets usually (like aero bar)

Chondrites

Stony meteorites that have not been modified due to melting or differentiation of the parent body

Chondrules form as molten or partially molten droplets in space before being accreted to their parent asteroids.

Are one of the oldest solid materials within our solar system- believed to be the building blocks of the planetary system

achondrites have no chondrules

Understanding their formation is important to understand the initial development of the planetary system.

Extraterrestrial

An asteroid is always going to be in space. Once it enters an atmosphere it becomes a meteor, then a meteorite if it hits the ground

Ablation

Melting upon re/entry to atmosphere

stony-iron rarest b/c limited space to come from

Comet

Two tails:
1. Plasma (indicates direction of sun)
2. Ice

Guyots

older as further away from hot spots

Huge column of upwelling lava, known as a “plume,” lies at a fixed position under the Pacific Plate.

As the ocean floor moves over this “hot spot” at about five inches a year, the upwelling lava creates a steady succession of new volcanoes that migrate along with the plate

Fossilised

Volcanoes

Shield - hottest, liquid lava

Conical - cooler than shield, more viscous lava

Can see eruptions occurred around darker/lighter surface areas (due to cooled lava)

Plate Boundaries

Convergent

Crust is destroyed and recycled back into the interior of the Earth as one plate dives under another. These are known as Subduction Zones - mountains and volcanoes are often found where plates converge.

There are 3 types of convergent boundaries: Oceanic-Continental Convergence; Oceanic-Oceanic Convergence; and Continental-Continental Convergence.

Divergent

new crust is created as wo or more plates pull away from each other. Oceans are born and grow wider where plates diverge or pull apart.

Mantle convection is the slow creeping motion of Earth's solid silicate mantle caused by convection currents carrying heat from the interior of the Earth to the surface - Leads to diverging through ridges

Transform

Where two plates are sliding horizontally past one another.
Earthquakes on surface.

Stratigraphy

Studies rock layers (strata) and layering (stratification)

Lithostratigraphy, is the most obvious visible layering.
- deals with the physical contrasts in rock type.

Such layers can occur both vertically - in layering or bedding of varying rock type - and laterally - reflecting changing environments of deposition

Biostratigraphy is based on fossil evidence in the rock layers. Strata from widespread locations containing the same fossil fauna and flora are correlatable in time.

This timescale remained a relative scale until the development of radiometric dating, which gave it and the stratigraphy it was based on an absolute time framework.

The geologic time scale was developed during the 19th century, based on the evidence of biologic stratigraphy and faunal succession.

It provides strong evidence for formation (speciation) of and the extinction of species.

Principle of Superposition
Younger rock deposited over old

Principle of Original Horizontality
Rock layers were initially deposited close to the horizontal

Sedimentary layers are laid down by deposition of sediment associated with weathering processes, decaying organic matters (biogenic) or through chemical precipitation.

Can take a long time, or might be instant - depends on what layers are made of and how they form

Same with sedimentation & tilting of layers

any cellular organism that has no nuclear membrane, no organelles in the cytoplasm except ribosomes, and has its genetic material in the form of single continuous strands forming coils or loops

unicellular

cross of horse and donkey, infertile so can't carry on dna

Order
Reproduction
Growth & Development
Energy Utilisation
Response to Enviro
Evolutionary Adaption