Earth Science Origins

Singularity

Area in space time where gravity is so high the laws of physics break down

3 Pillars of Proof

Recession of stars and galaxies, cosmic microwave background radiation, abundance of light elements

Edwin Hubble

Demonstrated many galaxies, measured distances in space, proves universe was expanding. Realized Doppler affect happened with light

How to determine the speed of a star

Using the redshift, the faster a star is moving away (think about Doppler affect)

Doppler affect

Pitch increases with sound waves that differ with the distance away that you are (think about an ambulance siren, it gets higher pitched the closer it gets to you because the wavelengths are shorter)

Hubble law

V = Ho D

Positive Curvature (universe shape)

Shaped like a sphere, closed, and finite which implies that there will eventually be a “Big Crunch” where it contracts again

Negative Curvature

Saddle shaped, open, infinite and unbounded, which implies that it will not have a contraction event

Flat universe

Infinitely expanding but eventually will approach zero, which means that the rate of expansion will stop but it will not contract

Conventional matter

Planets, asteroids, comets

Dark matter

Does not give off electromagnetic energy

Dark energy

Repels matter, counterbalances kinetic energy

How old is the universe and how do we know

Approx. 13 billion, used measuring dwarf stars who’s remnants are cooled off.

Measuring “near” distances of stars

Trigonometric parallax (measures stars wobble)

Measuring stars 500-500million light years away

Using “main sequence fitting” which involves the Hertzprug-Russel diagram to gauge luminosity and temperature, then determining distance

Hertzprug-Russel

Diagram that correlates the colour and luminosity of starts to the distance and temperature of them.

Cepheids

Stars with pulsing brightness, we measure the time between ‘peak’ brightness of stars

Measuring star distances beyond 500 million light years

Use Hubble Law ( V = HoD)

Nebular hypothesis

Big bang created matter, which formed nebulas (gas clouds) which contracted under their self gravity and in which pockets got closer and closer together eventually creating stars and planetary systems

Fission

Breakdown of nucleus into 2 lighter atoms and excess energy

Fusion

Combination of 2 lighter elements into 1 heavier one with excess energy

Supernova

Explosive death of a massive star

What were the first three elements and how did the rest form

The top three lightest elements - Hydrogen, Helium, and Lithium which eventually fused and created stars

Conservation of angular momentum

If no outside forces act on a spinning object, the angular moment will not change but instead the speed can increase, making the cloud contract and flatten (think of a figure skater)

Inner vs. Outer parts of the nebula

Inner parts - hotter, with more volatile elements that remain completely gaseous

Outer parts - cooler, where everything condensed into small particles and droplets

Refractory elements in nebula

Dont readily respond to heat that could condense and form strong chemical bonds (BUT CLOSER TO THE SUN ONLY THE HEAVIER ELEMENTS CONDENSE TOGETHER)

Accretion

Gentle moderate condensing / meeting of atoms

Planetismals

Small planet

Protoplanets

Big planets

Magic Broom / Solar Wind

Swept lighter gases to colder farther galaxy ends

Evidence of Bombardment Rates

Evidence in moon rocks, Uranus tipped on side, retrograde rotation of Venus, the moon, mercury’s orbital inclination

Red Dwarf

Sun that has run out of hydrogen fuel

Perihelion

Point of nearest approach of a planet to the sun

Apehelion

The point of greatest separation of a planet to the sun

What did Pythagoras and PLato ideas on planetary systems

Stationary earth, surrounded by a moving sphere of everything else

Artistarchus ideas on planetary systems

Library of Alexandria, put sun at the center and then moved on with no promotion of idea

Ptolemy ideas on planetary systems

Geocentric but all other objects are on moving spheres

Copernicus ideas on planetary systems

Heliocentric with earth on an axis, but was not published until his death

Galileo ideas on planetary systems

Improved telescopes, sunspots, Jupiter moons, and heliocentric model

Photosphere

Visible outer layer of a star

Chromosphere

Layer of gases outside a star

Corona

Outermost region of suns atmosphere

AU (astronomical unit)

Average distance between the sun and the earth

Sun chemical makeup

71% hydrogen, 27% helium

NASAs Genesis Mission

captured solar wind carrying samples of material from the sun, found isotopic composition of oxygen and nitrogen are different to everything else

Prominences

Arcs of gas that begin on the surface and extend to corona

Flares

Arcs of gas that begin on the surface but are shorter than prominences

Solar Maximum

Period of greatest solar activity, denoted by sunspots (region with lower average temperature)

Magnetosphere

Magnetic field volume around Earth that protects from solar winds, but is weaker at the poles- allowing for Aurora Borealis and Australis

Refractor telescope

Collect light by means of a glass lens

Reflector telescope

Collects lights with a curved mirror

Orbital and Escape Velocity

The energy required to put a satellite exactly in orbit or escape earth’s gravity

Geostationary satellite

Stays in the same spot above earth consistently regardless of orbit

asteroids

Dense objects orbiting the sun much smaller than planets

Comets

Icy objects orbiting in highly eccentric patterns

Terrestrial planets

Dense, made if silicon, oxygen, aluminum, magnesium, sulfur, and iron. fairly small (Mercury, Venus, Earth, and Mars)

Gas Giants

Huge, low density, made mostly of hydrogen and helium, surrounded by rings and satellites (Jupiter, Saturn, Uranus)

Ceres

Largest object in our solar systems asteroid belt. May even have an ocean and an atmosphere

Kuiper Belt

Icy bodies, largest are Eris and Sedna

Oort Cloud

Enormous belt of icy bodies on outer limits of solar system

Planet

A planet is a celestial body that orbits the sun, has sufficient mass/self-gravity to be round/oblate 3) clear around orbit

Dwarf Planet

Follows the same rules as planets, but has not cleared it’s orbit and not a satellite

Plutoids

Dwarf planets on outer regions of the solar system (Pluto, eris, Haumea, makemake)

“Nice” model

The largest four planets developed quickly, interacting with each others orbit and pushing each other away to the outer solar system

“Grand Track” model

Jupiter migrates inward, pushing planets inward by creating a smaller planetary disk, then gets caught by Saturn and moves out

Obliquely of planet

Angle between equatorial plane and its orbital/ecliptical plane that should be course to zero but itsn’t because planets get knocked around during reshuffling

Fission Hypothesis of moon formation

Moon broke off from a rapidly spinning earth (con: earth would have to rotate much faster for this to be possible)

Condensation hypothesis of moon formation

Earth and Moon formed contemporaneously from the same material (con: different material makeups and no equatorial plane orbit)

Capture hypothesis of moon formation

Moon formed as an independent planetary body and was “captured” by Earth (Con: incorrect gravitational conditions)

Giant impact hypothesis of moon formation

Planet smaller than earth (Theia) in unstable orbit collides with earth, melting both bodies, increasing Earths spin rate, combining metal cores, and magma mixes and cools into Moon in orbit around Earth (explains why isotopes of oxygen are so similar to earth and why the moon is so well mixed)

Earth atmospheric makeup

78% nitrogen 21% oxygen

Precession

As Earth rotates, it’s rotational axis moves causing positions of celestial poles to move

Accretion

Growth by accumulation of smaller bodies, dust and gas

Iron catastrophe (Earth)

Due to bombardment the Earth was melted, allowing for heavy iron to sink and form the core - this upheaving creating lots of energy

Differentiation

The process of chemical zonation from core to surface

Order of mantle layers

Lithosphere, asthenosphere, mesosphere, outer core and inner core

Lithosphere

Outer crust, relatively solid rocky outer layer

Asthenosphere

Heat softened, relatively weak and plasticy rock

Mesosphere

Confining pressure creating solid stiff plasticy rock

Inner core

Solid, nearly pure metal and hotter than suns surface

Outer core

Liquid Solid, nearly pure metal and hotter than suns surface

Dynamo

Liquid core spinning slightly faster than solid core, converting physical energy to electrical energy and generating a magnetic field

Alfred Wegener

German scientist who proposed the idea of continental drift

Paleomagnetism

The study of magnetic properties in rocks

Curie Point

Temperature point above which atoms get very active

Seismic tomography

Fragments of dropping lithosphere are cooler, so seismic waves pass through slower

Proterozoic

Precambrian period

Phanerorozoic

Postcambrian period (paleozoic, Mesozoic, Cenozoic)

Earths Asteroid Events

65.5 million years - 70/75% species death

251 million years - 96% species death

Why does Mars have a very thin atmosphere

Because it has less mass and a weaker gravity

Why does Venus have a thick atmosphere

Less water to dissolve the carbon dioxide building up

How did water cycle come to Earth?

Comments and asteroids left small quantities of water during bombardment period (it’s the only planet on which water can exist in liquid form not the surface)

Tidal coupling

Earth forces the moon into the exact same rotational and orbital period

Trojan satellite

Object on same rotational path but at a point that doesn’t collide

Lunar highlands

Lighter sides of the moon with more and older craters

Maria

darker areas of the moon, where most older or larger craters are filled with basalt lava

Sinuous rilles

Long winding channels that were once full of lava, can be found by the Maria on the moon - collapsed roof once lava drains

Meteoroid vs. Asteroid size

Meteoroids < 100m diameter < asteroids

Cumulative crater size frequency

Exposure time of surface increases → total number of craters increases

Luna 1

Soviet spacecraft launched in 1959, first spacecraft to reach the moon (didn’t land, that’s luna 9)