Exam

galaxy

large grouping of stars, gas, dust, and dark matter in space that are held together by gravity

types of galaxies

spiral - shaped like flattened disks with one or more spiral arms

elliptical - simply massive blobs of stars that are round or elliptical in shape and contains very little gas or dust(oldest)

irregular - don’t fit into any other category and are a chaotic mix of start, gas, and dust and are usually found near large spiral galaxies

nebulae

giant clouds of gas and dust where stars form

black holes

intense gravitational field left when a giant star collapses

parts of a black hole

photon sphere - the outer edge where light bends and is still escapable

event horizon - the point at which no light can escape

singularity - the shrunken star too small to be measured but with infinite density

nuclear fusion

a nuclear reaction in which two atoms are fused together, this process is responsible for creating all element in the universe; occur in the cores of stars

stellar nebula

a cloud of gas and dust that will collapse due to gravity and form a star, temperature and brightness increase and fusion will start

main sequence stars

wide range of colors and luminosities, medium sized; 90% of a star’s lifetime is spent here

giant and supergiant stars

exceptionally large and luminous, surface temperature decreases as star expands, explodes in a supernova at the end

white dwarf

small stars with high density, less bright, hotter

nova/supernova

the core of a giant star produces too much energy in its core and causes the outside of the star to expand, the outer layer of gases are blown out to space leaving behind a small hot core

neutron stars

form when extremely massive stars collapse after a supernova and protons get crushed together with electrons making neutrons. very small and dense

evidence of the big bang

1. the expansion of the universe - hubbles law
2. the abundance of hydrogen and helium
3. the CMB - cosmic microwave background radiation is still shown

big bang theory

it states that there was an infinitely small and dense point that contained everything that is the universe; occurred around 13.8 billion years ago

make up of the universe

4% atoms, 22% cold dark matter, 74% dark energy

red shift and blue shift/doppler effect

Redshift and blueshift describe the change in the frequency of a light wave depending on whether an object is moving towards or away from us. When an object is moving away from us, the light from the object is known as redshift, and when an object is moving towards us, the light from the object is known as blueshift.

life cycle of a star

apparent magnitude

how bright a star appears, not accounting for distance

absolute magnitude

how bright a star actually is, if it were placed at a constant distance

gravitational lensing

refers to one object being in front of another object. the object behind’s light bends around the object in front creating a “ring” of light. the object in front sometimes cannot be seen by humans and is evidence of dark matter

formation of the solar system

nebula-protosun is created-collapse-protoplanetary disk-condensation-planets-solar winds blow things away

reflecting telescope

uses two mirrors to collect light; newton’s telescope

refracting telescope

uses a glass lens to collect light; Galileo’s telescope

problems with earth-based telescope

earth’s atmosphere reflects certain wavelengths earth’s atmosphere blurs atmosphere light pollution

problems with space telescopes

expensive to launch and maintain difficult to repair relatively short lifetime

importance of Hubble telescope

Hubble has helped scientists learn about our solar system. The telescope observes comets and planets. Hubble even discovered moons around Pluto that had not been seen before. The telescope has helped scientists understand how planets and galaxies form

electromagnetic spectrum and astronomers

Telescopes use lenses or mirrors to collect and focus waves from the electromagnetic spectrum, including visible light, allowing us to look at celestial objects. By studying the electromagnetic waves given off by objects such as stars, galaxies, and black holes, astronomers can better understand the universe.

origin of the moon

4.5 billion years ago; earth and a mars sized object collided when the solar system was forming, then ejected pieces merged to form the moon

composition of the moon

made of similar rocks to earth; has a core, lower mantle, upper mantle, and crust; mostly igneous rocks

phases of the moon

new, waxing crescent, first quarter, waxing gibbous, full, waning gibbous, third quarter, waning crescent

highlands of the moon

lighter colored parts, high mountains, trench like valleys, impact craters

maria of the moon

darkest parts, large flat plains, mostly on near side, mostly basalt rocks

impact craters

formed when space objects crashed into the moon; lack of erosion keeps them visible; have ejecta(debris that shoots out); have rays(fine ejecta with bright streaks); have central peaks(only found on large craters)

solar vs lunar eclipse

A solar eclipse occurs when the Moon passes between Earth and the Sun, fully or partially obscuring the Sun's disk. A lunar eclipse occurs when the Moon passes through Earth's shadow, fully or partially darkening the lunar disk.

geocentric model

stationary earth and everything orbited around it; could not explain the aspects of planetary motion

heliocentric model

earth and everything orbited around the sun; provided explanation about retrograde motion

kepler’s first law

planets move in elliptical orbits with the Sun as a focus

kepler’s second law

planets move faster when they are closer to the sun

dwarf planets

Pluto, Haumea, Makemake, Eris, Ceres(asteriod belt)

comet

icy body that releases gas as it orbits the sun

asteroid

rocky body smaller than a planet that orbits the sun

meteoroid

rocky or metallic fragment of the asteroid, comet, or planet

meteor

streak of light seen when a meteorite heats up in the atmosphere

meteorite

meteor fragment that reaches the ground

terrestrial vs Jovian planets

They are opposite to terrestrial planets in many ways. Jovian planets are larger, further from the sun, rotate faster, have more moons, have more rings, are less dense overall and have denser cores than terrestrial planets. Jovian planets also have gaseous atmospheres, with the main gases being hydrogen and helium.

fossils

preserved remains or traces of once living organisms

original preservation

remains of plants and animals that have been altered very little since the organism’s death; these are rare because their preservations requires extraordinary circumstances such as freezing arid or oxygen free environments

altered hard parts (2)

mineral replacement - the pore spaces of an organism’s buried hard parts are replaced with minerals from groundwater

recrystallization - when a buried hard part is subjected to changes in temperature and pressure over time; original mineral is transformed into a new mineral

mold

forms when sediments cover the original hard part of an organism, such as a shell , and the hard part is later removed by erosion or weathering

cast

a mold might later become filled with material to create a cast of the mold

trace fossils

traces of worm tails, footprints, and tunneling burrow; can provide information about how an organism once lived

index fossils

fossils that are easily recognized abundant and widely distributed geographically - trilobites

relative age dating

using other rock layers/fossils to determine which layer is younger or older; doesn’t involve years but the order of event

absolute age dating

using radioactive decay to calculate half lives to find the numerical age of a rock layer/fossil; involves years

law of uniformitarianism

geological processes occurring today have been occurring since Earth formed

law of original horizontality

sedimentary rocks are deposited in horizontal or nearly horizontal layers

law of superposition

in an undisturbed rock sequence, the oldest rocks are on the bottom and each consecutive layer is younger than the layer beneath it

cross-cutting relationship

an intrusion is younger than the rock that cuts across it

unconformity

a gap in the geologic record; it looks like a wavy line in diagrams; represents erosion and sometimes uplift of an area

principle of inclusions

the fragments called intrusions in a rock layer must be older than the rock layer that contains them

correlations

is the matching of unique rock outcrops or fossils exposed in one geographic region to similar outcrops exposed in other geographic regions

how did life originate

4\.6 billions years ago the earth was formed, 3.2 billion years ago was the introduction of life


1. higher being
2. chemical synthesis - primordial soup
3. chemical synthesis - hydrothermal vents
4. panspermia

geologic time scale

eons - largest of these units

eras - ten to hundreds of millions of years

periods - ten of millions of years

epochs - hundreds of thousands to millions of years

order of mass extinctions

Ordovician, Devonian, Permian-Terrassic, end of Terrassic, end of Cretaceous

Ordovician

450 million years ago;85% lost; ocean temps and sea level fluctuations

Devonian

370 million years ago; 75% lost; food chain collapsed from cooling and volcanoes

Permian-Terrassic

250 million years ago; 95% lost; volcanoes were erupting and chemicals blocked the sun, which killed plants

end of Terrassic

200 million years ago; 75% land and 96% ocean lost; significant tectonic plate movement

end of Cretaceous

65 million years ago; 75% lost; asteroid strikes Earth and some volcanic activity

plamsa

when matter is heated to more than 5000C the collisions between particles are so violent that electrons are separated from atoms

5 main characteristics of a mineral

solid, naturally occurring, inorganic, specific chemical composition, definite crystalline structure

ways to identify minerals

crystal shapes, colour, streak, luster, breakage, hardness, texture, density, specific gravity, double refraction, effervescence, magnetism, iridescence, fluorescence

types of crystal form

cubic, tetragonal, orthorhombic, rhombohedral, monoclinic, triclinic, hexagonal

colour

least reliable clues to identify a mineral because minerals can be many different colours

streak

the colour of the dust left behind when a mineral is rubbed against a unglazed porcelain plate

luster

the way a mineral reflects light from its surface

fracture

minerals that break with rough or jagged edges

cleavage

minerals that breaks easily and evenly along one or more flat planes

hardness

measured on Mohs Hardness scale, it is the measure how how easily a mineral can be scratched; most useful way to identify a mineral

texture

the feeling of the mineral

density

causes the difference of weight in the same size minerals

specific gravity

measure of density; the ratio of the mass of a substance to the mass of an equal volume of water at 4 degrees

double refraction

a ray of light passes through the mineral and is split 2 ways

mineral groups

silicates, carbonates, oxides, sulfides, sulfates, halides, native elements, ores, gems

silicates

minerals that contain oxygen and silicon with one or more other elements; make up most minerals present in Earth's crust; has the silica tetrahedron pyramid shape

carbonates

one or more metallic elements and carbonate ion (CO3)

oxides

made of oxygen and a metal

sulfides

compounds of sulfur and one or more other elements

sulfates

with sulfate ion

halides

made up of chloride or fluoride with calcium, sodium or potassium

native elements

made of one element only

ores

mineral that contains a useful substance that can be mined of a profit; the classification can be changed if the supply or demand for the mineral drops

gems

valuable minerals that are prized for their rarity and beauty; they are hard and scratch resistant

igneous rocks

form from the cooling and solidification of lave or magma; they can be classified by the amount of silica they have; can show vesicular texture

sedimentary rocks

generally form from the compaction and cementation of sediments; can have fossils, ripple marks, and clasts

main agents of erosion

wind, moving water, glaciers, gravity

bedding

horizontal layering of sedimentary rocks

graded bedding

particle sizes become heavier and coarser toward the bottom layers

cross bedding

inclined layers of sediment are deposited across a horizontal surface

metamorphic rocks

rocks are changed as a result of exposure to intense heat and/or pressure without melting; can show foliation