Midterm Flashcards
What is a law?
A “Law” is something that has been proven
What is a theory?
A “Theory” is something that is extremely well supported, but we don’t have “proof” - Scientific community in agreement - Has not been disproven - ie. Evolution, climate change
What is a hypothesis?
An “Hypothesis” is something that could be possible, but is not yet well-supported
What are the seven steps in the big bang (or rapid expansion of the universe)
- The cosmos goes through a superfast inflation. Expanding from the size of an atom to that of a grapefruit in a fraction of a second (time 0, temp. N/A) 2. The universe is seething hot soup of electrons, quarks and other particles (time 10^-32 sec. temp. 10^27 C) 3. A rapidly cooling cosmos permits quarks to clump into protons and neutrons (time 10^-6 se ends at one secondc, temp 10^13 C) 4. Still too hot to form into atoms, charged electrons and protons prevent light from shining; the universe is a superhot fog (time 3 min. temp 10^8 C) 5. Electrons combine with protons and neutrons to form atoms, mostly hydrogen and helium. Light can shine through (time 300,000 years temp 10,000C) 6. Gravity makes hydrogen and helium gas coalesce to form the giant clouds that will become galaxies; smaller clumps of gas collapse to form the first stars (time 1 billion yrs, temp - 200C) 7. As galaxies cluster together under gravity, the first stars die and spew heavy elements into space; these will eventually form into new stars and planets (time 15 billion years temp - 270C)
Explain how we know the big bang occured
- Cosmic microwave background radiation - Radiation remaining from very early stages of the universe (~380 000 yrs) - Pattern matches that of a hot gas expanded to the size of the universe -T= 2.7 ± 0.0013 K 2. Distant galaxies are red shifted - Moving away from us (Doppler effect) - Hubble’s Law 3. Abundance of H and He - Universe expanded so rapidly, only H and He (and minor amounts of Li) could form Matter is 75% H, 24% - He, and 1% heavier elements 4. Dark energy - Expect the acceleration of the universe to slow down due to gravitational forces - In 1998, two group of scientists discovered it was accelerating - Einstein’s “cosmological constant”
What are the four key eras of the universe
- Forces and particles era 2. Star Formation era 3. Galaxy Formation and expansion era 4. Solar System formation era
Explain the forces and particle era of the universe
Involves steps 1 - 5 in the big bang 1. The cosmos goes through a superfast inflation. Expanding from the size of an atom to that of a grapefruit in a fraction of a second (time 0, temp. N/A) 2. The universe is seething hot soup of electrons, quarks and other particles (time 10^-32 sec. temp. 10^27 C) 3. A rapidly cooling cosmos permits quarks to clump into protons and neutrons (time 10^-6 se ends at one secondc, temp 10^13 C) 4. Still too hot to form into atoms, charged electrons and protons prevent light from shining; the universe is a superhot fog (time 3 min. temp 10^8 C) 5. Electrons combine with protons and neutrons to form atoms, mostly hydrogen and helium. Light can shine through (time 300,000 years temp 10,000C)
Describe the different eras in the forces and particles era
Includes all shown eras
Explain the star formation era
■H and He collide and accrete into stars
■Through fusion, produce heavier elements
–Up to Fe in main sequence
■Expand and super nova
■Energy from expansion and super nova used to form elements beyond Fe
–How we know our solar system formed after a super nova
What are the different types of stars?
- supergiants
- giants
- white dwarves
Explain the galaxy formation era
1 Gyr - present
■Matter was not perfectly uniformly distributed
–Some areas were more dense and attracted other matter
■Spiral galaxies cooled as they contracted
–Stars formed during this time
What are the different types of galaxy?
- elliptical galaxies
- normal spiral galaxies
- barred spiral galaxies
- irregular galaxies
Why did some regions have higher densities than others when galaxies form?
Dark matter
■Dark matter continues to exert gravitational influences on “normal” matter
■Most dark matter is in the halo of galaxies
Describe the universe’s composition in relation to dark matter.
■~70% of the universe is composed of dark energy
■~25% of the universe is composed of dark matter
■Only ~5% of the universe is made of “normal” matter
Explain the solar system formation era
Current era - solar systems are currently forming
believed solar systems formed based on the nebular theory which states:
a) Dust + gas (H, He) compressed by a supernova
b) Cloud contracts → rotates →faster rotation (disc)
c) Nuclear fusion (star)
d) First solid materials condense (calcium-aluminium inclusions and chondrules)
What proof is there for the nebular theory?
- astronomical observations
- cosmochemical observations
- numerical simulations
- space exploration
Explain why the inner planets are rocky and the outer planets are gaseous/icy
■The gas giants underwent orbital migration
■Uranus and Neptune formed closer to the Sun
–Not enough mass otherwise
■Resonances with Jupiter and Saturn moved them outwards
–Also threw around some asteroids and used the energy to move outwards
–Late heavy bombardment
Explain how we know the Late Heavy Bombardment occurred
■Six manned Apollo missions (1969-1972) returned 382 kg of lunar rocks and regolith
■the ages of lunar polymict breccias, especially impact-melt breccias, which show a strong clustering near 3.9 Ga
What are protoplanetary disks?
■In the Interstellar Medium (ISM), dust (<0.1 microns) is composed of silicates, graphite and polycyclic aromatic hydrocarbons (PAHs)
■Most of the gas is diatomic, molecular hydrogen (H2), which accounts for 99% of the total mass of the ISM and initially protoplanetary disks
■Stars form from gravitational collapse of molecular cloud cores (cold, dense portions of the ISM containing gas and dust)
–Material flows inward
–Forms a protostar and disk
■After 100,000+ years
–T-tauri star surrounded by a protoplanetary disk (proplyd)
Explain how solar systems form
■Dust in the proto-planetary disc starts colliding and accreting
■Eventually forms planetesimals
–Pulls in nearby material
–~10 km in diameter in ~10,000 years
■Planetesimals grow quickly to moon-sized bodies (~10^5 years)
–“Runaway growth” phase
■Planetesimals continue accreting until they are Mars-size
–~10^6 years, “orderly growth”
■Late-stage collisions
–Planets have cleared out all their neighbours
–Collisions only happen due to orbital perturbations
~10^7-8 years
Explain Late Heavy Borbardment or lunar catacylsm
■4.1 – 3.8 Ga
■A disproportionately large number of asteroids collided with the infant terrestrial planets
What are planetary geology objectives?
Scientific goals for Solar System Exploration:
–How did our solar system form and evolve?
–Is there life beyond Earth?
–What are the hazards to life on Earth?
What do planetary geology objectives hope to answer?
Science goals to answer these questions:
–Explore and observe the objects in the solar system to understand how they formed and evolved
–Advance our understanding of the chemical and physical processes operating in our solar system
–Improve our understanding of the origin and evolution of life on Earth
–Identify and characterize object in our s.s. that are potentially life-threatening hazards and offer resources for human exploration
Who decides the direction of space exploration?
■The scientific community identifies and prioritizes science questions and the observations required to answer them
■Formal reports and workshops
■Decadal Surveys
What are the different planetary science methods?
- Planetary Geomorphology
–Creating geologic maps from satellite data
–Laboratory and computer simulations of geological processes in different planetary environments
–Analogue studies
- Spacecraft Data
–Remote Sensing Data
- Visible, hyperspectral, thermal, altimeter, and RADAR
Explain how geological maps are used in planetary science
■A geological map shows rock units, rock ages or geological strata depicted by color or symbols
■Maps rock units exposed at the surface
■Contour lines may be used to show topography
Describe analog sites or space analogues and their use in planetary science
Areas on Earth with geological conditions such as geological, environmental or biological conditions that may approximate the past or present conditions on extraterrestrial bodies (Mars / Moon)
–Desert Research (Black Point Lava Flow, Arizona)
–Underwater off Key Largo Florida
–Pavilion Lake Research Project (BC)
–Mauna Kea (Hawai’i)
Inflatable Lunar Habitat Analog Study (Antarctica
What is remote sensing?
Remote sensing is the science of obtaining information about objects or areas from a distance
–typically from aircraft or satellites
What is spectroscopy?
Spectroscopy is the study between the interaction of matter and electromagnetic radiation
How can laboratories be used within the planetary science methods?
Laboratories with equipment that can simulate conditions on or within other planetary bodies
–Example: High temperature gas-mixing furnace or multi-anvil cell (high pressure experiments)
How can remote sensing data and EMR be used in planetary science methods?
■Remote sensing data makes use of electromagnetic radiation (EMR)
■Remote Sensing instruments are designed to detect specific parts of the EMR spectrum
–Three main types:
–UV-VIS
–VIS-NIR
- TIR
How are spectra acquired?
■Spectroscopy is the study of spectra
■Imaging spectroscopy is the study of images (usually the surface of a planetary body) composed of spectra
■Passive systems use natural radiation (sunlight); active systems use an artificial energy source (radar or laser altimeter)
■Imaging spectroscopy works with reflectance spectra
- Incoming light is reflected off the surface and its spectrum is altered based on the interaction with surface material
What is visible imaging data and how is it used?
■Most imaging systems use charge-coupled devices (CCDs)
–CCD chip has an array of pixels onto which light is focused by a lens causing a pattern of electrical charges to be received
–Light focused on the chip creates a pattern of electrical charges – the charge on each pixel is proportional to the amount of light received
■Simple systems = single wavelength (λ) range
■Wavelength range can be narrow or “broadband”
■Color images are produced by obtaining data for more than one wavelength over the same scene
- Red-Blue-Green (RGB) frames combined to produce a colour image
What is hyperspectral data?
In the visible near infrared (VNIR) minerals absorb energy
–Absorption bands
–Characteristic of specific minerals or groups of minerals
–Multispectral spectrometers measure the reflected energy as a function of wavelength
What is thermal data and how is it used?
■Surfaces emit or radiate energy (“heat”) in the infrared range of the EM spectrum, which can be recorded as digital files and transformed into images
■Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) uses a similar approach to map the distribution of minerals on Earth
■Thermal Emission Imaging System (THEMIS)
■Images in infrared and visible parts of the EM spectrum at 9 different wavelengths (λ)
–8 have λ between 6 and 13 micrometers (ideal region of infrared spectrum to determine the thermal energy patterns for silicate minerals)
■THEMIS has a high spatial resolution (100 m) with a low spectral resolution
■THEMIS also has a visible imaging camera that acquires data in five spectral bands with a spatial resolution of 18 m / pixel
- ■Intermediate between:
–Viking Orbiters (150 to 300 m per pixel)
–Mars Orbiter Camera (MOC) onboard Mars Global Surveyor (1.5 to 3 m per pixel)
■TES has a low spatial resolution (3x6 km) with very high spectral resolution of 143 bands between 5 and 50 micrometers
What is HiRise?
■High Resolution Imaging Science Experiment : exploring Mars one giant image at a time
–Camera onboard Mars Reconnaissance Orbiter (MRO)
–0.3 meters per pixel
What is a laser altimeter and how is it used?
■Bounce a laser off the surface and record two-way return time
–Locations closer to the satellite have a shorter two-way return time
■Used to map elevation
Why is radar imaging data important?
■Without Radar we would know nothing about the surface of Venus and Titan, otherwise obscured by clouds
■Radar = Active remote sensing technique
■Radar systems mounted on airplane / spacecraft send short pulses of radio waves obliquely, striking the surface at an angle
■Reflected energy received as an echo
■Several thousand pulses / second at speed of light
List different in-situ instruments that can be used in studies?
■Spectrometers
–VIS-NIR
–TIR
–Mössbauer
–APXS
–XRD
■Cameras
–Panoramic
–High-res
■Scoops, RATs, brushes
■Chemical analysis suites
■Wind/weather suite
■Sky observation
■Geothermal detection
■Seismic detection
What different instruments are used on probes?
■Atmospheric chemistry suite
■Altimeter
■Accelerometers
■Cameras
■RADAR
What is planetary differentiation?
process of separating different constituents of a planetary body as a consequence of their physical and/or chemical behavior
Explain Goldschmidt’s Classification of the Elements
■Goldschmidt (1937) classified the elements into four groups based on the way in which the elements distribute themselves among iron liquid, sulfide liquid, silicate liquid, and a gas phase
Explain why Earth has a differentiated planetary interior
■In magma ocean, dense elements sink and light elements rise
■Dense iron diapirs (blobs) accumulate in core taking siderophile (iron loving) elements downward
–Also some chalcophile (sulfur loving) elements
■Lighter silicate material migrates towards the surface
–Buoyant molten rock rose to the surface; take lithophile silicate loving) elements
–Si, Al, Ca, Na, K, Fe and Mg
■Result: Layering by chemical composition:
–Crust
–Mantle
–Core
Identify sources of heat to the Earth
■Continued tectonic activity on Earth is driven by asthenospheric convection in response to temperature differences
■Heat sources:
–Conversion of the kinetic energy of planetesimals into heat during impact
–Decay of naturally-occurring radioactive elements (long and short-lived)
–Compression of the Earth as its mass continued to rise
–Release of gravitational potential energy by molten iron sinking toward the center of the Earth
–Tidal heating (Earth-Moon)
List the different types of plate boundaries
■Divergent boundaries or spreading centers
–lithosphere being pulled apart
■Convergent boundaries
–lithosphere crunching together
–subduction zones or collisional boundaries
■Transform fault boundaries
–plates slide past each other
Identify the different types of faulting and folding
- reverse or thrust fault
- strike slip faults
- folds
- ductile formations
- Not sure this is right or everything difficult to tell from notes because there are notes on compression, tension and shearing
Explain partial differentiation and the role it plays in determining magma composition
■Zones of up-ward converging convection (mantle hot spot or divergent plate boundary) tend to erupt mafic lava (Mg- and Fe-rich)
–Partial melting of ultramafic mantle generates mafic melt
■Volcanoes associated with subduction tend to erupt intermediate and felsic lava (more Si-rich)
–Fractional crystallization in a magma chamber and / or assimilation of felsic crust drives magma compositions towards enrichment in silica
NOT sure if this is correct only thing in the right area of the lecture that I could find
Describe the factors that affect the type of volcano and eruption
■Explosive
–Driven by the release of gases in the magma as it reaches the surface
–Release pyroclastic materials (glass, ash, mineral & lithic fragments, spatter, bombs)
■Effusive
–Magma erupted on the surface as liquid (low viscosity) lava flows
Identify different types of volcanoes and volcanic features
- Shield Volcanos
■Very low angle slopes
–Basaltic lavas
■Lower silica, lower viscosity, lava flows farther
■Largest volcanoes / mountains on Earth & in solar system
- Stratovolcanos
■Large conical shaped
■Steep slopes (6-10º at base, 30º at summit)
–Typically andesitic lavas
–More silica, more viscous, don’t flow as far
■Layers of lava and tephra (ash)
- Lava Domes and Block Lavas
■High viscosity felsic lavas don’t readily flow, but rather they build up lava domes or block lavas
- Cinder Cones
■Built from particles and chunks of congealed lava ejected from a single vent
■Often small
–Rarely more than ~1000 ft high
■Can be on the flanks of other volcanoes
■Common in volcanic terrains
- Lava Tubes and Pit Craters
■Lava tubes are conduits that develop as roofed channels in some basalt flows
–Insulate lava and allow it to flow great distances from the main vent
■When conduits are emptied the roof can collapse and produce a chain of small collapse features (<1 km) called pit craters
- Volcanic Calderas
■Volcanic craters with diameters >2 km are called calderas which can form by collapse, explosion, erosion or a combination of these processes
Describe divergent boundaries and a least one physiographic property
■Two (or more) plates moving away (diverging) from each other
–Creates long, narrow fractures
–Magma from the mantle rises to fill the gap as the crust is ripped apart
–Magma cools to produce new crust
–Repeat
■Also called spreading centres
■Occur in oceans and in continents
Describe convergent boundaries and a least one physiographic property
■Two plates converging
–Crust is destroyed or deformed
■Also called subduction zones
■Three types:
–Ocean-ocean
–Ocean-continent
–Continent-continent
Describe transform boundaries and a least one physiographic property
■Two plates slide past each other horizontally
■No creation or destruction of lithosphere
■Discovered by Canadian geoscientist J. Tuzo Wilson in 1965
–Proposed that they connect two spreading centres or subduction zones
■Most occur on the ocean floor but some occur on land
What is an astroid?
A big (>1 meter) rock or aggregation of rocks in orbit around the Sun
What is a meteoroid?
A small (<1 meter) rock orbiting the Sun
What is a meteor?
- The visible light that occurs when a meteoroid passes through the Earth’s atmosphere
- It is an atmospheric phenomenon
What is a meteorite?
■A rock found on Earth that was once a meteoroid
■A revised, more technical definition of meteorite is: “A natural, solid object larger than 10 microns in size, derived from a celestial body, that was transported by natural means from the body on which it formed to a region outside the dominant gravitational influence of that body and that later collided with a natural or artificial body larger than itself (even it if was the same body from which it was launched).” Rubin and Grossman (2010) Meteoritics & Planetary Science, v. 45:114-122.
What is a fireball?
■an exceptionally bright meteor
–Heat from friction and rapid compression of air in front of the meteor
–Produces light (colours may vary)
What is evidence is there for atmospheric transit?
- Fusion crust is a thin, glassy rind on the exterior of the stone formed by melting during heating as it transits earth’s atmosphere
- Regmaglypts thumb-shaped depressions on exterior from uneven melting
How does Mercury compare in surface to volume ration in comparison to other planets?
- S/V decreases with increasing values of planetary radii; these ratios are qualitatively related to cooling rate because the amount of heat lost by radiation depends on its surface area relative to its volume
- Mercury’s interior is still hot, but its lithosphere is thick, preventing decompression melting and magma from reaching the surface
Explain why rough surfaces appear bright and smooth surfaces appear dark in RADAR data
■Radio Detection and Ranging
■Signal sent out from satellite and bounced off surface
–Return time and strength determine distance from source and surface roughness
■For images from Venus, rougher surfaces represented as white
Explain the runaway greenhouse effect on Venus
Compare the convection currents of Venus’s atmosphere to Earth’s
Explain the magma ocean hypothesis
Explain the evolution of LMO and the lunar mantle and crust
1 - the evolution of the magma ocean by fractional crystallization
2 - simultaneous impact brecciation of the crust (megaregolith and regolith)
3 - later partial melting of the mantle and the formation of chemically distinct basaltic lava flows due to mineralogical zoning of the mantle
