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104 Cards in this Set
- Front
- Back
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What are the distance units on Earth?
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Kilometers or Miles
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What are the distance units in our solar system?
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AU- Astronomical Unit
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What is 1 AU equal to?
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it is the average earth-sun distance and is 93 million miles
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What are the distance units for inter stellar?
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Light Years- distance that life travels in 1 yr.
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What is a light year equal to?
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5.67 trillion miles
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What is a par sec?
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3.26 light years
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What are the 3 effects of a large distance on our search for life in the universe?
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1. signal delay- still there now?
2. Very weakened signal 3. enormous travel time - greater than a lifetime |
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What are characteristics of Radio and infrared waves?
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longest wavelengths
shortest frequency lowest energy |
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What are characteristics of X rays and Gamma Rays?
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shortest wavelengths
highest frequency highest energy |
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What is the atmosphere transparent to?
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visible light and some transparnecy to Infrared and radio
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What is the atmosphere opaque to?
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-Many inrared rays blocked fomr H2O vapor
-Some Radio -UV (ozone) -X Rays & Gamma Rays |
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What is the importance of these rays being blocked?
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The blocking of UV,X, and Gamma rays allow for life to exist on Earth's surface
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What is a negative for rays being blocked that effects communication with possible other life forms?
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Many wavelengths cannot pass through earth atmosphere so no signals are received and it may affect signals that are sent out from earth
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What are terrestrial planets and their characteristics?
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Mercury, Venus, Earth, Mars & they are small, dense, warm, and revolve fast
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What are jovian planets and their characteristics?
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Jupiter, Saturn, Uranus, & Neptune & are gas giants (H/He), cold, huge, many moons/rings
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What is the age of the Solar System?
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4.6 billion years
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What is the lifetime of the Sun?
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10 Billion years
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What is the radius from the sun to pluto?
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40 AU
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What is the radius from the sun to oort cloud?
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50,000 AU
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What is the composition of the Milky Way Galaxy?
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200 billion stars, spiral galaxy, 4 or 5 spiral arms
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What are the parts of a spiral?
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it is the galactic center, galactic disc, and galactic halo
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What is the Principle of Mediocrity?
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A. Our sun is 1 of billions of similar stars- not unique/special
B. Milky Way is just 1 of millions of galaxies- not unique/special C. Planets form around other stars D. Spectroscopy: Chemicals found on Earth/Sun are found everywhere E. Laws of chemistry/physics are universal F. Biological Implication - if life exists here, why not elsewhere |
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What is the consequence of Earth's fast rotation?
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-day is not too long and not too hot
-night is not too long and not too cold -small day/night temperature difference -Earth average distance b/w day and night - 14-17 degrees |
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What is the earth daily temp.?
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63 degrees F (liquid water)
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What is the atmosphere made of?
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78% diatomic Nitrogen
21% diatomic oxygen small traces of h2o,co2, o3 and others |
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Earth has the correct amount of what?
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correct amount of atmosphere, chemical makeup, mixture of chemicals
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What is the greenhouse effect?
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chemicals that hold in inrared radiation and serves as a blanket
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what is the major gas of of greenhouse?
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CO2
(lesser H20 & o3) |
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What is the would the temp. be on Earth if there were no greenhouse effect?
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-9 degrees F (No Liquid Water)
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What does the greenhouse effect allow for?
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it reduces the amount of heat lost on night side and causes small day/ night temperature difference and is more conducive to life
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What is the H2O cycle?
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Source is evaporation, it sinks with percipitation and creates an equilibrium
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What is the CO2 biological cycle?
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source: respiration
Sink: photosynthesis |
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What is the chemical CO2 cycle for sink?
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-CO2 dissolves in rain
for the sink: -as it percipitates, CO2 is removed from atmosphere -CO2 chemically locked in rocks on ocean floor |
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what is the source chemical CO2 cycle?
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vulcanism and tectonic activity release heat from earth's interior and creates an equilibrium
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What is the ozone layer made from?
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O3 - triatomic oxygen
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Where is the ozone layer located?
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30-50 KM above surface
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What is the purpose of the ozone layer?
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Block UV light
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Why is it important that the ozone blocks UV light?
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because UV can destroy H2O water Vapor
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What is the retention of H2O?
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it is what prevents H2O form rising above the ozone layer
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How does the troposphere interact with altitude?
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Temp decreases with increased altitude
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What is the cold trap?
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10Km above surface which is region where H2O cannot be a gas and cannot rise any further
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What is the buffer zone?
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where no H2O vapor and no UV exists
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In terms of cold trap what does a warmer planet signify?
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a higher cold trap
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What is the structure of Earth's interior?
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Crust, Mantle, Lithosphere, Core, Outer Core, Inner Core
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What is the crust?
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thin, low density (basalt & granite)
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What is the Mantle?
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3000 Km thick, medium density silicates
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What is the lithosphere?
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crust & upper 100 Km of mantle
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What is the core?
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highest temps., highest density, made of nickel and iron
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what is the outer core?
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molten iron/nickel
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what is the inner core?
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sold iron/nickel
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What are the conditions that allow for a magnetic field?
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-molten core/region (outer core)
-electrically conducting substane -fast rotation |
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What does the magnetic field create?
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The magnetosphere
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What is the function of the magnetosphere?
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to trap/block/deflect electircally charged particles (protons/electrons)
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What is the solar wind?
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A stream of fast moving protons/electrons
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What does the solar wind create?
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The aurora
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What does the magnetosphere prevent?
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Atmosphere erosion by the solar wind
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What are Earth's 3 characteristics that LAWKI maintains for habitability?
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-significant energy source - the sun
-organic compounds - carbon -chemical medium for life - liquid water |
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What is the habitable zone?
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the region in the vicinity of a star where temp. are such that H2O, if it exists, will be in liquid form
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What is the energy source for our habital zone?
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sunlight
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What affects the HZ (or a planet's temp)?
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-distance to sun
-intensity/luminosity of the star -"albedo"/reflectivity of a planet -amount of greenhouse effect |
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Why is the width of HZ important?
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If there is a wide HZ there are more planets that form within it which lead to more chances for life and n increases and N increases
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What if there is a narrow HZ?
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fewer planets form within it and there are fewer chances for life
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****Why is earth's signifacnt mass important for habitability?****
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-large gravity allows the retaining of atm
-warmer interior - geology -> replenishes atm in greenhouse gases -warm interior ->molten core -> strong magnetic field |
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What does fast rotation help in terms of habitability?
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-strong magnetic field
-affect small day vs. night temp. differences |
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What are the variables that go into Earth's habitability?
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-Atmosphere
-Key Earth Characteristics -Greenhouse Effect -H2O cycle -CO2 Cycle -Ozone Layer -Retention of H2O -Structure of the Earth's Interior -Magnetic Field |
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What is the chemical makeup of the Sun?
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He, H, C, O, N, Ne
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What is the chemical makeup of the Earth?
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Fe, Ni, Si, Mg, O, S
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What is the chemical makeup of Jupiter?
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H, He, N, C, Ne, O
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What is the chemical makeup of humans?
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H, O, C, N, Ca, P
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What is the chemical makeup of bacteria?
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H,O,C,N,P,S
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What is the chemistry of life similar to and different to?
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Chemistry of life is different from chemistry of earth but is similar to the chemistry of the stars and of sea water
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What conclusions can now be made***?
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-we are all made from stars
-life was not created from primordial elements which forced surface/interior -life most likely began in oceans -chemicals that are important for life (H2, O, C) are not primordial to Earth -life began on earth and did not come from space ("panspermia") -life in oceans->ozone->protection from UV->life on land! |
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What characterizes life?
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Reproduction & evolutionary adaptation; genetic mutation & natural selection
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What is the mass of venus?
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80% of earth's mass
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What is the radius of Venus?
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95% of Earth's radius
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What is the expectation from the radius and mass of venus?
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-that there would be a warm interior ->magnetic field
-geologic processes -> source of CO2 -Strong gravity -> can hold an atm. |
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Where is venus located?
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28% closer to Sun which is the same neighborhood as Earth
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How does Venus' composition compare to Earth?
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nearly identical composition
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What are some misconceptions of Venus?
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-that the white clouds are h2O vapor
-cloud movements signify fast rotation -expected surface temp nearly identical to Earth that would allow for h2o & life |
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What are the truth to the above misconceptions?
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-The clouds are sulfuric acid
-Rotation period =243 earth days (day is greater than year) -extremely weak magnetic field -day & night temp. is about 900 degress |
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What are the current condiditons of Venus?
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-extremely hot
-extremely thick atmosphere 90x pressure than earth -95% of atm is co2 -very few craters ->covered by lava flows -no liquid h2o ->not in HZ |
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What were the early conditons of Venus?
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-cooler- liquid h2o existed
-atm. must have been thinner -lesser greenhouse effect -balance of sources/sinks of h20/co2 |
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What was the process of change that made Venus like it is today?
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-venus is closer to sun
-sun is getting brighter -venus becomes warmer -h2o evaporates -greenhouse & temp. increases -volcanoes inrease greenhouse -as planet warms there is no rain (no h20 of co2 sink) -atm thickens -repeat the steps many times |
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What are the long term results of the process for Venus' change?
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-oceans boil away
-all of venus' co2 is in atm -runaway greenhouse -h20 keeps rising -> UV dissociates h20 -no magnetic field -> H blown away by solar wind |
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What is the inner boundary for the habital zone?
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.85-.95 AU
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What are similarites b/w earth and mars?
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-same length of day
-same tilt -experience seasons -temp. are not so dissimilar to Earth |
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What are Mars' differences with Earth?
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-distance is 1.52 AU
-rec. 43% as much energy as earth -mass = 11% of mass of earth - highly elliptical orbit -> large changes in its distance from the sun |
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What are the current conditions of mars?
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-dry planet -> no liquid water
-usually cold -> day temp. <32 degrees and night temp is -180 degrees -very little atmosphere -no greenhouse effect -96% of atm is co2 -lots of h2o on mars in polar caps and permafrost -lots of huge dormant volcanoes |
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What is the evidence of past liquid H20?
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-dry river beds
-dry tributaries -tear drop islands->floods -hematite and jarosite found ->only form in presence of h20 |
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What conclusions can be made about Mars?
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it was once in the HZ, must have been warmer, must have had a thicker atm. and larger greenhouse
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What is the evolution of Mars in early conditions?
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once had warmer climate,thicker atm., balance of source and sinks, must have had geologic activity
->warmer interior |
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What is the evolution of Mars for consequences of a small planet mass?
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-cool interior ->no molten core and no/weak magentic field
-weak gravity ->harder to hold atm. -cool interior ->loss of vulcanism -> loss of CO2 source |
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What is the evolution of Mars in atm. loss process #1?
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very weak magnetic field & solar wind erosion
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What is the evolution of Mars in atm. loss process #2?
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-small mass ->loss of vulcanism which means mars lost its source of co2 back into the atm.
-atm. thins;greenhouse decreases; planet cools |
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What is the evolution of Mars in atm. loss process #3?
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-mars is near the asteroid belt
-with each asteroid encounter, small pieces of atm are swept away -b.c mars is small; weak gravity could not hold atm -"asteroid impact erosion" |
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IS there life on Mars?
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-on surface no! there is no liquid h2o and too much UV light
-in the crust there may be subsurface liquid h20, protection from UV, and interior heat (probably b.c of meteor impacts) |
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What was the results of the 1976 voyager king mission?
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searched for life in martian crust but got negative results
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What was the results of the meteroite found in antartica?
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there were organic molecules found and could be micro fossils but not enough evidence
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what is the conclusion on Mars?
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Life FAR too outside the HZ
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What is the evidence that Europa may be able to have life?
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strong tidal heating flexing from jupiter can create a warm interior and form liquid h2o. There is a chance for organic chemicals
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What is the evidence that Titan may be able to have life?
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-Atm. chemicals on Titan match those of pre-biological Earth (Nitrogen, CH4, Ammonia- organic chemicals)
-But There is no liquid h20, no significant energy source -May be liquid ethane that causes rain and oceans on titan |
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What is kepler's 1st law and equation?
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the planet's distance from the sun changes during an elliptical orbit
r=a(1-e*e)/[1+e(cos)] |
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What is kepler's 2nd law and equation?
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A planet's speed changes during its orbit
v(squared)=Mk[2/r - 1/a] |
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What is Newton's improvement of kepler's 3rd law and equation?
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MP(squared) = a(third)
Using the Sun's revolution period aroudn the galaxy and applying this law we can count how many stars are in the galaxy without really counting them |
