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Description
Flashcards by Olivia Gniadek, updated more than 1 year ago
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Created by Olivia Gniadek
about 6 years ago
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| Question | Answer |
| Could you distinguish between Earth and Sun-centered solar system models by observing Venus with a telescope? | Yes Galileo did this Saw the phases |
| Why are the planets closest to the Sun more dense than those farther from the Sun? | When formed a temperature gradient was present, more heavier solar material could solidify closer, lighter material wouldn't :. material availability |
| What is the solar wind? | charged particles from sun |
| Where do asteroids come from? | come from the formation of early solar system |
| If Earth was more reflective (had a higher albedo), what would happen to its temperature? | Sunlight would be reflected into space, wouldn't be absorbed therefore earth would be cooler |
| What are the main constituents of Earth's atmosphere? | Nitrogen and Oxygen |
| Which of the following is not a characteristic of jovian planets? | molten core crust |
| How did Ptolemy's model differ from Aristotle's model of the universe? | Aristotle perfect circles Ptolemy was the deference in epicycles |
| Why are smaller terrestrial bodies such as Mercury or the Moon "geologically dead"? | the radioactive decay has decreased to such a degree :. no longer molten (internal structure) |
| At any given time, how many high tides are there on Earth? | 2 high tides one on the moon side of the earth and one one the side facing the sun |
| What are Some of the features of Auroras? | Due to magnetic field occur in polar regions due to solar wind coming in contact with the earth's atmosphere |
| Where do comets come from? | Come from Kuiper belt (icy and rocky) or the Oort cloud ((pertubated) kicked out by being closer to Jupiter = rockier) |
| What is the main reason that Venus is warmer than Earth? | Runaway greenhouse effect |
| Which of the following planets has the most oxygen in its atmosphere? | Earth has most oxygen |
| What are some of the features of Primitive meteorites? | Early formation of solar system Rocky |
| Jupiter does not have a large metal core like Earth. How can it have a magnetic field? | Metallic hydrogen, acts like a metal :. causes magnetic field |
| Why do the lunar highlands have many more craters than the lunar maria? | Older Maria's formed after large bombardment :. lunar highlands are smoothed out |
| Why do we think Mars was once warmer and wetter? | Evidence of water, once had rain water flowed on surface |
| How does Io get heated by Jupiter? | tidal heating causes massaging effect |
| Asteroids have the following features | 10s of metres to 100s of kms Irregular shapes |
| Which of the following planets has the most dense atmosphere | terrestrial: Venus |
| What age does radiometric dating give for Moon rocks and meteorites? | 4.6 billion years |
| What is the structure of Jupiter like? | Core - rocky Metallic Hydrogen Predominant features Clouds |
| Which of the following is not one of Kepler's laws of planetary motion? | deferents and epicycles select the option that is not these 1. The orbit of a planet around the sun is an ellipse with the sun at one focus 2. A line joining a planet and the sun sweeps out equal areas in equal times 3. The square of an orbital period (P) of the planet is proportional to the cube of the semi-major axis (a) of the orbit |
| Why do we think that the solar system formed from a rotating, collapsing gas cloud that ended up as a disk orbiting the Sun? | All the planets orbit the Sun in the same direction planets have right characteristics to have formed from a disk of mainly hydrogen around a young, hot Sun Observations of Sun agree with the theory of a giant ball of mostly hydrogen generating heat by nuclear fusion in the core. |
| What do we think the composition of the solar nebula was? | Hydrogen Helium Other Planets and Sun are made out of these |
| Which bodies show evidence of a substantial atmosphere? | Mercury - no Venus - yes Earth - yes Mars - not really |
| What is the main source of the original atmospheres of the terrestrial planets? | Volcanic outgassing Original Atmospheres |
| What are the most common elements in the atmospheres of the jovian planets? | Hydrogen |
| Meteorites come from where? | Debris of comets and dust |
| Suppose a comet had a very eccentric orbit that brought it quite close to the Sun at closest approach (perihelion) and beyond Mars when furthest from the Sun (aphelion), but with an average distance of 1 AU. How long would it take to complete an orbit and where would it spend most of its time? | 1 year Further out beyond Mars |
| If there was no greenhouse effect, how would Earth be different? | Cooler |
| What is the shape of a planets orbit | Nearly circular |
| What are terrae | Highlands on the moon's surface |
| What happens with the earth and the moons tidal waves | Side closest to the moon attracted stronger -> gives a bulge of water on the near side Side farthest from the moon is attracted least -> leaves a bulge of water of the far side This gives a double sided tidal bulge |
| What are some other ways that solar wind can make its presence known | Comet tails are pushed away from sun Heliopause maybe ~100AU away |
| What is the ion tail in a comet | Ionised atoms from coma Accelerated by solar wind; pointed away from sun Straight but does exhibit filamentary structure which can change daily Bluish colour Up to 1AU long |
| What is the scale of the outer regions of the solar system? | Planetary System = ~40AU radius Heliopause = ~100AU radius |
| Where in the Milky Way are we located | In the Orion Spiral Arm |
| How many exoplanets have we found thus far | Over 3,498 exoplanets |
| What is the composition of the sun | 74% Hydrogen 25% Helium 1% other |
| What is the direction of rotation of the planets | Clockwise apart from Venus which spins backwards and Uranus which spins on its side |
| What is the plane that all planets orbit along called and are all orbits the same? | Ecliptic plane Planets orbit is almost the same |
| What is the approximate tilt of the planets axis | ~30 degrees |
| What are the similarities between Venus and Mars | Similar topography Similar size Formed similarly to earth |
| How long is the rotation period of Jupiter? | Similar to the sun, the colourful belts of Jupiter rotate different ways I.e. left, right, left etc. |
| What do the colours on Jupiters surface represent? | Different chemicals, temperatures and atmospheric height differences that the chemical clouds are forming under |
| How big is Jupiter's red spot? | 20,000km x 10,000km |
| What determines a shape of an object | If an object is warm and cools down slowly, it's gets a round spherical shape If an object cools quickly it forms an abnormal shape |
| What are the characteristics of Saturn's moon: Titan | Rain, clouds and sleet are made out of methane and ethane It's cool enough that methane could be a liquid or a gas Has liquid hydrocarbons It has waves like our oceans do |
| How can we determine the chemical composition of a planet | Using the colour spectrum once sun is behind the planet (concept for exoplanets is the same) |
| What is the density of water on earth in comparison to other planets mass | Earth's water = 1,000kg/m3 Mercury = 5x the density of water Jupiter = less density of water Saturn could float on water, that is if you find an ocean big enough |
| How dense is the asteroid belt | Thinly spread, if all matter in the asteroid belt was clumped together it would form a small moon. Definitely not like Star Wars |
| Where does solar and cosmic radiation come from | Solar from the sun Cosmic from other sources in space |
| Where on earth are the auroras located and what are the aurora areas called | In the North & South poles Northern = Borealis Southern = Australis |
| What is the key to Ptolemy's model: the epicycle and the deferent | A planet moves in a small circle otherwise known as an epicycle The centre of the epicycle moves along a larger circle called a deferent which is approx. centred on earth |
| What are inferior planets and elongation | Orbits that are smaller than earth's The angle between the sun and a planet as viewed from earth |
| What are superior planets and opposition | Orbits that are larger than earth's Planet is in opposition part of the sky to the sun (visible at night) |
| What is an ascending node? | The point where'd the planet (moving in it's orbital period) crosses the ecliptic from south to north |
| What is a descending node? | The point where the planet crosses the ecliptic from north to south |
| What is the sequence of events from the Big Bang? | BIG BANG - H, He, Li, Be,- galaxy formation - nucleosynthesis in stars- new elements - generations of stars - big stars create supernovas - interstellar medium enriched with heavier elements I.e. Fe, C, N, O etc |
| What happens at hotter temperatures | More isolated atoms I.e. H and Fe Ionisation of atoms (if hot enough) e.g. H+ or Fe++ Plasma - ionised gas/atoms |
| What happens at colder temperatures | Atoms form molecules i.e. H2, NH3, CO, N2, H2O Materials solidify I.e. ice, dust and rock Form metals, metal oxides, silicates erc |
| What does our galaxy contain | Centrally located nucleus of millions of stars Spiral arms - lanes of interstellar gas, dust and young stars Interstellar medium ion between stars |
| What does the interstellar medium contain | Molecular clouds - cool gas and dust Inter cloud gas - region between clouds (less dense and warmer) Bubbles of hot gas - due to supernovas |
| What are the characteristics of the giant molecular clouds | Weak magnetic fields Different sizes and masses Cold temperatures 10-50K Mainly molecular hydrogen (H2) Perhaps 1% microscopic dust and ice Contain small dense regions |
| Case study: Bok Nebula "Barnard 86" | Core remnant of a molecular cloud 410 light-years 12,500AU 16K 2x greater in mass than the sun Pressure at boundary = 0.0025nPa Clouds like this can form isolated low mass stars |
| Where does most of the mass in our solar system lie | In the sun, angular momentum is in the planets |
| What was the sequence of events in the formation of the solar system | Enriched molecular cloud compression - cloud core of new star system - solar nebula - matter attracted to nebula - Protosun develops - gas, dust, ice form disk - planets established - nebula with small residual rotation - core contracts (200,000AU-50AU) - rotation of nebula increases - nebula flattens out |
| Why are there different types of planets | 1. Solar nebula had radial temperature gradient 2. Materials condensed into solids at different temperatures |
| What are the rock forming substances | Silicates, metals etc Solid at night temperatures Solid nearly everywhere in solar nebula |
| What are the molecular compounds like water | Water, methane and ammonia Solid at low temperatures ~100-300K Not much solid in the inner solar system When solid - called ices More ice than silicates Hydrogen molecules and helium never solidify in the nebula |
| What are the different temperature gradients in the different zones of the solar nebula | Innermost (terrestrial) warm, 300-1200K Metal/ silicate materials solid if not too close to protosun Any idea vapourised and not readily accreted Intermediate (Jovian) cold, ~50-200K Metals, silicates, and ices stable solids All available for accretion Outer (cometary) colder, <30K Metal, silicates, ices stable solids Material is too sparse - inhibits planet building Rocky/icy planetissimals - comet nuclei (Kuiper Belt) |
| What is the planet building system | Accretion of planetissimals to form planets A. 100 planetissimals (~1km size) orbiting the sun B. After 30 million simulated years have 22 protoplanets C. >100 million years - some well established planets |
| What is the consolidation stage | Inner zone Planet sized ball of metal, oxides and silicates Intermediate zone Growing planet sized ball of metal compounds, silicates and ices Grow larger than earth due to ice Planet cools and shrinks Outer zone: Icy planetissimals (~kms in size) dispersed thinly to accrete efficiently Millions of objects |
| What is the cleanup stage | 1. Radiation pressure 2. Solar wind 3. Mopping up of debris by planets 4. Close encounters with other planets |
| What is earth's internal structure | Core: 0-3500kms Ni & Fe Mantle: Liquid iron alloy outer core Solid iron alloy core Crust: Low density rock Floats on mantle Thinner under oceans ~10km thick |
| What is mercury's internal structure | Core: 75% of planet (diameter) Mantle 600 km thick Small magnetic field - some molten core |
| What is oblateness | Measure of how much a flattened sphere differed from a perfect sphere |
| What does oblateness depend on | Size of planet Rotation rate Matter planet is formed from How the matter is distributed inside the planet |
| What is the system of heating of the planets for rocky bodies | Object (like earth) entirely molten Differentiation creates a layered structure Heavier material sank to the core Lighter material floated to outer layers Cooling over time Outer layers solidify first Larger bodies cool slower than smaller bodies Need liquid conducting core |
| What is the internal structure of Jupiter | Core: Rocky inclination I.e. Fe, Ni & Si High density Liquid metallic hydrogen Molecular hydrogen Colourful band patterns in the top 100kms Low density H and He abundant Strong magnetic field |
| What is the internal structure of Uranus and Neptune | Rocky core Mantle compressed water with some ammonia Layer of liquid molecular hydrogen and liquid helium with a small amount of methane + clouds above |
| What are the moons physical characteristics | Diameter: 3476 km Gravity: ~1/6 earth Sidereal period: 27.332days Average surface temperatures: 403 K (day) 93 K (night) Albedo: ~0.1 Angular size: ~1/2 degrees Average density: 3340 kg/m3 |
| What are Maria's | Lowlands on the moons surface |
| What are the types of rocks found on the surface of the moon | Igneous, meaning that the surface of the moon was once molten. Basalt: found in the mare, dark, typical of cooled lava Anorthosite: found in the highlands, light colour |
| What is the composition of the moon | Regolith: fine powder and rock fragments covering the moon's surface; |
| What is the structure of the moon | Mare on moons crust Crust - solid, brittle, less dense material Solid upper mantle Non-rigid inner mantle Core: iron rich |
| What is the moon doing annually | Receding from earth at ~ 4cm/yr, this slows the earth's orbit by 0.002 seconds per century |
| What does the height of tides depend on | Height of high tides vary due to the effected of sun's gravity Spring (larger) Neap (weaker) tides |
| What are planetary surface temperatures due to | Solar heating (depends on distance from planet to sun and its albedo) The surface temperature of the planet also affects the planets atmosphere |
| What is albedo | The fraction of radiation reflected back into space E.g. Albedo 1 ~ all radiation reflected Albedo 0 ~ no radiation reflected |
| What happens if an object absorbs energy at a higher rate that it can radiate away | It only gets hotter. As the object gets hotter, it radiates more. |
| What happens if sunlight reaches a planet with no atmosphere vs with an atmosphere | No atmosphere: infrared radiation escapes into space Atmosphere: some infrared radiation is absorbed in the atmosphere whilst the rest escapes into space. This causes the planets temperature and atmosphere to rise |
| What are the differences between terrestrial and Jovian planetary atmospheres | Minimal (compared to terrestrial planets) Implies... less processing of the atmosphere |
| What are the levels in the earth's atmosphere? | Troposphere - 0-12km, 80% of atmospheric mass, weather zone, clouds & pollution Stratosphere - ~12-50km, ozone region, heating of region Mesosphere - 50-80km Thermosphere - ~80+km, thin, windiest zone |
| What are the levels in venus' atmosphere | Lower atmosphere - hot, dense, clear Cloud layer - 3 separate levels, lower level most opaque, thin haze exists both above and below cloud layer Cloud composition - sulphuric acid droplets, no rain on surface, high temperatures, acid and sulphur based components |
| What are the planetary atmospheres of Uranus and Neptune | Uranus - 2% methane (greenish blue), featureless (no water or ammonia), 98% rotation axis tilted, global circulation issue? Neptune - more dynamic than Uranus, high clouds, faint belts & zones, internal heating driven |
| What is the source of solar wind and what are its characteristics | The corona Not dense Plasma (charged particles) that becomes solar wind |
| What are the characteristics of cosmic rays | Non-solar source of radiation in the solar system Composition: ~87% protons, ~12% alphas Particle numbers are less than a solar flux wind Energy of the particles are greater than solar winds |
| What are the characteristics of earth's magnetic shield | Shock front: Where the solar wind is slowed to subatomic speeds Magnetopause: Where the pressure of earth's magnetic field balances the solar wind pressure |
| What are the characteristics of Jupiters magnetosphere | Huge: envelops the orbits of several moons Solar radiation gets trapped and emits synchrotron radiation at radio wavelengths Lower energies - radio Higher energies - x-rays |
| What happens with auroras in terms of planets without an atmosphere e.g. Venus | Solar wind impacts directly on the upper atmosphere ionising the gas Shock region develops where the solar wind is slowed and interacts with the atmosphere |
| What happens with auroras on Mercury and Mars | Mercury - weaker field 1% that of earth's, similar process to earth but smaller scale, too weak to trap radiation Mars - no globular magnetic field but does have some magnetised regions in its crust |
| What are comets | Few kms in diameter Irregular shapes Loose collection of ices, water, methane, ammonia and carbon dioxide, and rocks Low albedo Covered in black material Crust maybe carbon rich As it reaches sun, ice vapourises Comet surface emit jets of vapourised material in sunlight |
| What is the coma of a comet | Dense gas & dust cloud surrounding comet Hides nucleus 10,000,00 - 10,000,000km in diameter Gases flow - fuzzy ball appearance |
| What is the hydrogen cloud | Huge sphere (10^7km diameter) Surrounding coma and nucleus Hydrogen seen in UV not visible wavelengths and comes from UV dissociated water molecules |
| What is the dust tail in a comet | Fine dust particles freed from evaporating nucleus ~0.1-1 micrometer in diameter Curved smooth shape Combo of solar photons 'radiation pressure' and gravity - points away from the sun Faint yellowish appearance |
| What forms a meteor shower | As a comets nucleus evaporates it leaves behind a trail of dust and rock fragments in the same orbit, it earth passes through this orbit it's called a meteor shower |
| What is a meteor/oid/ite | The brief flash of light visible where a meteoroid enters the surface If it survives and reaches the ground it's called a meteorite |
| What are the three categories of meteorites | Stony - 95% Iron - 4% Stony iron 1% |
| What are the characteristics of stony meteorites | Look like ordinary rocks Possible fusion crust Difficult to find if weathered |
| What are the characteristics of a stony iron meteorite | Equal amounts of iron and silicates |
| What are the characteristics of iron meteorites | Contain 10-20% nickel Prior to 2000BC main source of refined iron Large nickel iron crystals; only possible if the material cooled slowly |
| What are the characteristics of large asteroids | Molten interior with thin crust similar to terrestrial planets |
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