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104 Cards in this Set

  • Front
  • Back
What are the distance units on Earth?
Kilometers or Miles
What are the distance units in our solar system?
AU- Astronomical Unit
What is 1 AU equal to?
it is the average earth-sun distance and is 93 million miles
What are the distance units for inter stellar?
Light Years- distance that life travels in 1 yr.
What is a light year equal to?
5.67 trillion miles
What is a par sec?
3.26 light years
What are the 3 effects of a large distance on our search for life in the universe?
1. signal delay- still there now?
2. Very weakened signal
3. enormous travel time - greater than a lifetime
What are characteristics of Radio and infrared waves?
longest wavelengths
shortest frequency
lowest energy
What are characteristics of X rays and Gamma Rays?
shortest wavelengths
highest frequency
highest energy
What is the atmosphere transparent to?
visible light and some transparnecy to Infrared and radio
What is the atmosphere opaque to?
-Many inrared rays blocked fomr H2O vapor
-Some Radio
-UV (ozone)
-X Rays & Gamma Rays
What is the importance of these rays being blocked?
The blocking of UV,X, and Gamma rays allow for life to exist on Earth's surface
What is a negative for rays being blocked that effects communication with possible other life forms?
Many wavelengths cannot pass through earth atmosphere so no signals are received and it may affect signals that are sent out from earth
What are terrestrial planets and their characteristics?
Mercury, Venus, Earth, Mars & they are small, dense, warm, and revolve fast
What are jovian planets and their characteristics?
Jupiter, Saturn, Uranus, & Neptune & are gas giants (H/He), cold, huge, many moons/rings
What is the age of the Solar System?
4.6 billion years
What is the lifetime of the Sun?
10 Billion years
What is the radius from the sun to pluto?
40 AU
What is the radius from the sun to oort cloud?
50,000 AU
What is the composition of the Milky Way Galaxy?
200 billion stars, spiral galaxy, 4 or 5 spiral arms
What are the parts of a spiral?
it is the galactic center, galactic disc, and galactic halo
What is the Principle of Mediocrity?
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
What is the consequence of Earth's fast rotation?
-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
What is the earth daily temp.?
63 degrees F (liquid water)
What is the atmosphere made of?
78% diatomic Nitrogen
21% diatomic oxygen
small traces of h2o,co2, o3 and others
Earth has the correct amount of what?
correct amount of atmosphere, chemical makeup, mixture of chemicals
What is the greenhouse effect?
chemicals that hold in inrared radiation and serves as a blanket
what is the major gas of of greenhouse?
(lesser H20 & o3)
What is the would the temp. be on Earth if there were no greenhouse effect?
-9 degrees F (No Liquid Water)
What does the greenhouse effect allow for?
it reduces the amount of heat lost on night side and causes small day/ night temperature difference and is more conducive to life
What is the H2O cycle?
Source is evaporation, it sinks with percipitation and creates an equilibrium
What is the CO2 biological cycle?
source: respiration
Sink: photosynthesis
What is the chemical CO2 cycle for sink?
-CO2 dissolves in rain
for the sink:
-as it percipitates, CO2 is removed from atmosphere
-CO2 chemically locked in rocks on ocean floor
what is the source chemical CO2 cycle?
vulcanism and tectonic activity release heat from earth's interior and creates an equilibrium
What is the ozone layer made from?
O3 - triatomic oxygen
Where is the ozone layer located?
30-50 KM above surface
What is the purpose of the ozone layer?
Block UV light
Why is it important that the ozone blocks UV light?
because UV can destroy H2O water Vapor
What is the retention of H2O?
it is what prevents H2O form rising above the ozone layer
How does the troposphere interact with altitude?
Temp decreases with increased altitude
What is the cold trap?
10Km above surface which is region where H2O cannot be a gas and cannot rise any further
What is the buffer zone?
where no H2O vapor and no UV exists
In terms of cold trap what does a warmer planet signify?
a higher cold trap
What is the structure of Earth's interior?
Crust, Mantle, Lithosphere, Core, Outer Core, Inner Core
What is the crust?
thin, low density (basalt & granite)
What is the Mantle?
3000 Km thick, medium density silicates
What is the lithosphere?
crust & upper 100 Km of mantle
What is the core?
highest temps., highest density, made of nickel and iron
what is the outer core?
molten iron/nickel
what is the inner core?
sold iron/nickel
What are the conditions that allow for a magnetic field?
-molten core/region (outer core)
-electrically conducting substane
-fast rotation
What does the magnetic field create?
The magnetosphere
What is the function of the magnetosphere?
to trap/block/deflect electircally charged particles (protons/electrons)
What is the solar wind?
A stream of fast moving protons/electrons
What does the solar wind create?
The aurora
What does the magnetosphere prevent?
Atmosphere erosion by the solar wind
What are Earth's 3 characteristics that LAWKI maintains for habitability?
-significant energy source - the sun
-organic compounds - carbon
-chemical medium for life - liquid water
What is the habitable zone?
the region in the vicinity of a star where temp. are such that H2O, if it exists, will be in liquid form
What is the energy source for our habital zone?
What affects the HZ (or a planet's temp)?
-distance to sun
-intensity/luminosity of the star
-"albedo"/reflectivity of a planet
-amount of greenhouse effect
Why is the width of HZ important?
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
What if there is a narrow HZ?
fewer planets form within it and there are fewer chances for life
****Why is earth's signifacnt mass important for habitability?****
-large gravity allows the retaining of atm
-warmer interior - geology
-> replenishes atm in greenhouse gases
-warm interior ->molten core
-> strong magnetic field
What does fast rotation help in terms of habitability?
-strong magnetic field
-affect small day vs. night temp. differences
What are the variables that go into Earth's habitability?
-Key Earth Characteristics
-Greenhouse Effect
-H2O cycle
-CO2 Cycle
-Ozone Layer
-Retention of H2O
-Structure of the Earth's Interior
-Magnetic Field
What is the chemical makeup of the Sun?
He, H, C, O, N, Ne
What is the chemical makeup of the Earth?
Fe, Ni, Si, Mg, O, S
What is the chemical makeup of Jupiter?
H, He, N, C, Ne, O
What is the chemical makeup of humans?
H, O, C, N, Ca, P
What is the chemical makeup of bacteria?
What is the chemistry of life similar to and different to?
Chemistry of life is different from chemistry of earth but is similar to the chemistry of the stars and of sea water
What conclusions can now be made***?
-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!
What characterizes life?
Reproduction & evolutionary adaptation; genetic mutation & natural selection
What is the mass of venus?
80% of earth's mass
What is the radius of Venus?
95% of Earth's radius
What is the expectation from the radius and mass of venus?
-that there would be a warm interior ->magnetic field
-geologic processes -> source of CO2
-Strong gravity -> can hold an atm.
Where is venus located?
28% closer to Sun which is the same neighborhood as Earth
How does Venus' composition compare to Earth?
nearly identical composition
What are some misconceptions of Venus?
-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
What are the truth to the above misconceptions?
-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
What are the current condiditons of Venus?
-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
What were the early conditons of Venus?
-cooler- liquid h2o existed
-atm. must have been thinner
-lesser greenhouse effect
-balance of sources/sinks of h20/co2
What was the process of change that made Venus like it is today?
-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
What are the long term results of the process for Venus' change?
-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
What is the inner boundary for the habital zone?
.85-.95 AU
What are similarites b/w earth and mars?
-same length of day
-same tilt
-experience seasons
-temp. are not so dissimilar to Earth
What are Mars' differences with Earth?
-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
What are the current conditions of mars?
-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
What is the evidence of past liquid H20?
-dry river beds
-dry tributaries
-tear drop islands->floods
-hematite and jarosite found ->only form in presence of h20
What conclusions can be made about Mars?
it was once in the HZ, must have been warmer, must have had a thicker atm. and larger greenhouse
What is the evolution of Mars in early conditions?
once had warmer climate,thicker atm., balance of source and sinks, must have had geologic activity
->warmer interior
What is the evolution of Mars for consequences of a small planet mass?
-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
What is the evolution of Mars in atm. loss process #1?
very weak magnetic field & solar wind erosion
What is the evolution of Mars in atm. loss process #2?
-small mass ->loss of vulcanism which means mars lost its source of co2 back into the atm.
-atm. thins;greenhouse decreases; planet cools
What is the evolution of Mars in atm. loss process #3?
-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"
IS there life on Mars?
-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)
What was the results of the 1976 voyager king mission?
searched for life in martian crust but got negative results
What was the results of the meteroite found in antartica?
there were organic molecules found and could be micro fossils but not enough evidence
what is the conclusion on Mars?
Life FAR too outside the HZ
What is the evidence that Europa may be able to have life?
strong tidal heating flexing from jupiter can create a warm interior and form liquid h2o. There is a chance for organic chemicals
What is the evidence that Titan may be able to have life?
-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
What is kepler's 1st law and equation?
the planet's distance from the sun changes during an elliptical orbit

What is kepler's 2nd law and equation?
A planet's speed changes during its orbit

v(squared)=Mk[2/r - 1/a]
What is Newton's improvement of kepler's 3rd law and equation?
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