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246 Cards in this Set
- Front
- Back
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What is the summer and winter solstice?
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the shortest and longest day of the year
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what is intercalation?
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insertion of a leap day, week or month to follow the season or moon phases
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what might lunisolar calendars require?
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intercalation of both day and month
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Who used lunisolar calendars?
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Bablonians and assyrians, Greeks
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who uses lunar calendar?
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Islam
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who uses solar calendar?
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Julian and Gregorian
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If the moon is at a new moon at one of its nodes, what type of eclipse occurs?
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Solar
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If the moon is at a full moon at one of its nodes, what type of eclipse occurs?
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Lunar
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Who can see a lunar eclipse?
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everyone at hte nighttime side of the earth
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what is the moon's tilt?
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5 degrees to the ecliptic plane
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At a total lunar eclipse, what will the moon look like?
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red glow
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At a partial lunar eclipse what will it look like?
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a normal full moon with a shadow on lower right corner
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At a penumbral lunar eclipse what will the moon look like?
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normal full moon
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what will the moon look like at a total solar eclipse?
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dark center with light ring
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what will the moon look like at a partial lunar eclipse?
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red glow of hte sun with a dark circle (moon) covering half of it
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What will it look like at a solar eclipse?
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just dark
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where do sun moon and stars rise and set in?
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rise in east, set in west
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are the star pattersn same in the sky year after year?
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yes
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does the sun appear to trace a path in the sky?
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yes
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when does sun appear highest in the sky?
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summer
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how fast does earth rotate per day on its axis and how long does it take?
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23 hrs and 56 mins, 600 mph (1000 km/hr)
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what is the earth's average distance from the sun?
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1 au = 150 million km
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how fast does the earth revolve around the sun?
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100,000 km/hr
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are the lengh of apparent solar days the same?
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No
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how long is the average solar day?
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24 hrs
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How can you tell its been a year without using a metric?
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length of day, patterns of stars in teh sky (repeats), orientation of the moon
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how much does a solar/tropical year (from solstice to solstice) differ?
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20 mins because of precession
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how long is a sidereal month?
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27.3 days
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how long is a synodic month?
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29.53 days
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what is the celestial sphere?
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imagine earth as a bowl, the way stars all appear fixed and same distance from earth
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what is the zenith?
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the point overhead
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what is the horizon?
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where earth and sky meet
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what is the meridian?
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half circle from s horizon to zenith to s horizon
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what can you use stars for, navigationally?
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finding if you're North or South hemisphere, declination and right ascension
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Polaris is how far from NCP?
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1 degree
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If you travel south, is polaris more or less overhead?
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less
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how does sky appear to rotate?
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around celestial poles
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if you are standing at a pole, do things appear to rise and set?
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no
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if you are standing on the equator, how do things rise and set?
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at 90 degrees
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is polaris a permanent north star?
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no, because of precession
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how long does a precession cycle take?
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26,000 years
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12,000 years from now, what will be the north star?
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Vega
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how much does sun move in respect to the stars per day?
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1 degree, 360 degrees in 365 days
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how much later does the sun rise per day?
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about 4 minutes
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what si the zodiac?
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constellations sun moves through
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what is the eclipctic?
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path of the sun
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what is apparent retrograde motion?
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planets slowly move eastward through the 12 constellations of the zodiac
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what were copernicus' assumptions?
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- earth and universe spherical
- universe is very large - sun is at center - earth rotates on axis and orbits the sun - distance from earth to sun very small compared to that between earth and other stars - earth is one of several planets - |
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what is a synodic period?
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- apparent period of orbit in relation to the sun (opposition to opposition, or conjunction to conjunction)
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what is a sidereal period?
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actual period of orbit around sun wtih respect to the stars
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For an inner planet, during 1 synodic period it has made 1 more trip around the sun than early, therefore if S = synodic and P = sidereal...
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1/P = 1+1/s
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For an outer planet...
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1/p = 1-1/s
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what are problems with copernicus' model?
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- still ha no proof the earth moved
- still has uniform circular motion adn few epicycles - couldn't explain lack of stellar parallaxes - planetary positions predictions not much better than ptolemy's |
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what did Tycho Brahe do?
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1563: observed conjunction of Saturn and Jupiter - timing DAYS away from prediction
1572: observed Supernova 1577: observed comet - showed it was outside earth's orbit - designed his own astronomical instruments - made 20-30 years of the most accurate pre-telescopic planetary data ever collected - rejected copernicus nd came up with his own model (thought sun orbited earth) |
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What did Bruno do?
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- defended heliocentric model
- argued universe was infinite with lots of living beings - burned as a heretic |
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What did Kepler do
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- beliver in copernicus
- worked for tycho - succeeded tycho after death - found out mars's orbit was an ellipse |
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in kepler's equation e = c/a, what is c?
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c is the distance from the center to the focus
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in an elliptical orbit, what is the closest point to the sun called?
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the perihelion
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in an elliptical orbit, what is the farthest point to the sun called?
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aphelion
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how do you calculate aphelion distance?
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a distance = a(1+e)
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how do you calculate perihelion distance?
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perihelion distance = a(1-e)
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if p is in years and a is in au, what is kepler's equation for that relationship/
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p2 = a3
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What is a summation of kepler's laws?
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1) planets orbit sun in elliptical orbit with sun at one focus
2) planets move faster when closer to sun, slower when farther away 3) p2=a3 (kepler didn't know why these worked, just knew that htey did) |
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what is the south star called?
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sigma octantis
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what did galileo do?
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-1st scientist to do experiments
- time for pendulum to swing is same no matter size of object - an object set in constant motion will continue moving in contant motion - in a vacuum, falling objects fall with uniform acceleration, no matter mass or size - distance an object has fallen is the square of time is has been falling |
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what'd huygens discover?
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- rings of saturn
- Titan, saturn's largest moon - showed tha tcircular motion was accelerated motion where A = V2/R |
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What is newton's first law?
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an object in motion continues in motion, an object at rest remainsi n rest until force impacted. momentum = mv
change in p/change in t = 0 dp/dt = 0 |
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what is newton's second law?
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change of motion is proportion to the force impressed, and in th edirection of the straight line in which that force acts
F = ma |
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what is newton's 3rd law?
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forces occur in pairs that are always opposite and equal in direction, total momentum is conserved
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how does the moon "fall" around the earth?
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in 1 second, moon moves 1 km and fall .14 cm to the earth
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What is the equation for what you weigh on another planet?
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Mone/Manother x Rone/Rother
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how does newton's 1st law apply ot astronomy?
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an object moving around the sun and subject to its gravitational force will orbit in a conic section
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how does newton's 2nd law apply to astronomy?
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if the orbit is closed, then the conservation of angular momentum will explain the law of areas. if distance is decreased, velocity will increase
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what is p2 = a3 applicable towards?
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object orbiting sun where p is years and a is in au
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when are tidal forecs strongest?
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when moon(s) and suns are aligned (spring tides)
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when are tidal forces weakest?
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when at 90 degree angles with suna dn earth. (neap tides)
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how do you compare tidal forces?
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Mone/Mother x Done/Dother
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do tides quicken or slow earth's rotation?
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slow bc of friction
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what do tidal forces do to earth?
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- stretch into a prolate spheroid with major aixs pointed towards the moon
- earth slows rotation, day gets longer - angular momentum conserved, so moon must be spiraling away from earth - as moon moves farther, earth moves slower |
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what happens if velocity is less than 8m/sec?
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its a ballistic missile
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if object has circular orbit than
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v = circular orbit v
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if object has elliptical orbit than
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v > circular orbit v
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if object has a parabolic orbit
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than it has escaped
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what are proof of newton's laws?
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- discovery of uranus and neptune
- artificial satellites - rockets |
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what is a planet?
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orbiting a star
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what is a moon?
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orbiting a planet
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what is a star?
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large glowing ball of gas
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what is galaxy?
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100 million stars
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what does a light yr equal?
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10 trillion km, 10^12,
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what does 1 AU equal in light minutes?
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8.3 light minutes
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how close is nearest star?
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4.3 light yrs
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how fast does milky way rotate?
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1million km/hr, one orbit in 230 million years
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how fast does milky way go in relation to other galaxies?
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300,000 km/hr
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are galaxies moving towards or away from each other?
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away
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antigravity causes...
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supernovas
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what was universe originally made of ?
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hydrogen
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in stars what is hydrogen ocnverted to and why?
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helium, nuclear fusion
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in dying stars, what is helium converted to?
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carbon
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in largest dying stars, what does carbon fuse up to?
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iron
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when they explode, what do they fuse into?
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uranium
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where are molecules found?
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interstellar space
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what are atoms?
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elements
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wha tis teh atomic number?
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number of protons
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what is the atomic weight?
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# of protons and neutrons
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what is an isotope?
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same #p, different #n (same element, different atomic weight)
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in a vacuum, how fast does light travel?
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300,000 km/second, 3x10^8 m/second
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does speed of light change if observer is moving?
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no
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what is the frequency of light?
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# of waves(Cycles)/sec = hz (top of wave to top of wave)
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what kind of radiation is light?
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electromagnetic
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what is a photon?
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a particle of light
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what does energy depend on ?
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frequency
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can light of a particular energy knock off electrons of certain metal films?
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yes
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what does longer wavelength mean?
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lower frequency
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does red have longest or shortest wavelength?
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shortest
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does violet have longest or shortest wavelength?
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shortest
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what rays have shortest wavelength? Second shortest?
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gamma rays, xrays
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what rays have longest wavelength?what has the second longest?
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radio waves, microwaves
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whar relative wavelength does visible light have?
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righ tin the middle
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what happens to transparent light?
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it's emitted
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what happens to opaque light?
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it's absorbed
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what is luminosity?
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total amount of power (energy/second) that a star radiates into space
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what is apparent brightness?
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amount of starlight reaching earth (energy per second per square meter)
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does the same amount of starlight pass through each sphere?
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yes
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what are 4 major characteristics of universe?
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- large bodies in solar system have orderly movements
- planets are either rocky or gaseous - swarms of asteroids and comets populate solar systems - several notable exceptions to general trends stand out (like moons w unusual orbits) |
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does temperature increase or decrease with distance from protostar?
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decrease
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how does radioactive decay work?
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measure the rate of radioactive decay of unstable elements within crystals of certain elements. decay rates are constant, amount of original elements can be used to date things
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are decay rates affected by thing sin physical and chemical environment?
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no
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how much of nucleus do electrons take up?
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100,000 x radius of nucleus
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who discovered nucleus
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Ernst Rutherford
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what hcarge does proton have?
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positive
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what are the two subatomic particles that occur in the nucleus, the proton and the neutron called?
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nucleons
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what is halflife?
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time required for one half of unstable nuclei to decay
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do living organisms have same or different amount of c14 than exist sin their environment?
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same
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is carbon added after deaht?
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no
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where do liviing organisms get carbon from?
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food and air
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wha tis stable form of carbon?
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c-12
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what is estimated age of milky way/
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11 billion yrs
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what is estimated age of universe
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13.6 billion years
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what is estimated age of meteorites?
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4.54 billion years
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how old are rocks on earth
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baout 3.5 million years old
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how old are moon rocks?
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4.4-4.5 billion years
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what is cenezoic era?
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age now, time of recent life
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what is mesazoic era?
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time of middle life, some fossils resemble life now, some different
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what is paleozoic era?
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time of ancinet life, fossils different from anythiing found on earth today
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what is precambrian eartH?
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time before ancient life, very few fossils
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what is a period?
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what eras were divded into
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what is an epoch?
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what periods are divided into
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what was hadean earth like?
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bombarded frequently, earliest earth cruth and surface water but frequently destroyed by bombardments, widespread melting and vaporized hydrosphere.
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what are three zones of molten planets?
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- core (made of metals)
- mantle (made of dense rock) - crust (made of less dense rock) |
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what is the lithosphere?
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the rigid, outer layer of crust and part of the matnle which does not deform easily
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what are terrestrial bodies in our planetary system?
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Earth, venus, mars, mercury, moon
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how do planets heat up in terrestrial world?
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1) accretion (gravity potential energy converted to kinetic, then to thermal)
2) differentiation ( light materials rise to surface, dense fall to floor making gravity potential area to thermal) 3) radioactivity ( mass energy in nuclei converted to thermal energy) |
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how do planets cool off in terrestrial world?
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1) conduction (heat flowing on microscopic level)
2) convection (heat flowing on macroscopic levels) 3) eruptions (hot lava bursts through crust) |
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if a planet if larger, will it take longer or shorter to cool off?
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longer!
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what happens when a rock hits planet at 10-70 km/s?
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vaporizes rock, creates crater, matter ejected in all directions,
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what do large craters have?
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central peak
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how are craters shaped?
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htey're circles
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the older teh planet, the more or less cratering evidence?
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more
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are solar systems being hit with more or fewer rocks?
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fewer
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what is volcanism?
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molten rock, called magma breaks through lithosphere
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what gases are released in a volcanic eruption?
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H20, Co2, N2
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what does viscosity of lava depend on ?
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type of volcano tectonics
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what do convection cells in the mantle cause?
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compression in lithosphere, mountians produced, and extensions in lithosphere, valleys produced
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what are types of crusts on earth?
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1) seafloor crust (high density basalt, young <200 million yrs, 5 to 10 km thick
2) continental crust (low density, eg granite) old as much as 4 bill yrs old, 20-70 km thick 3) new balsat forming at mid-ocean ridges because of seafloor spread it is pushed in both directions 4) seafloror is pushed under continental crust at ocean trenches (called SUBDUCTION, seafloor crust partially molten and less dense lava erupts through underwater volcanoes) |
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what are continents shaped by?
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- volcanism
- stresses from plate tectonics - erosion |
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what do subduction zones cause?
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- volcanic eruptiosn which cause mountains
- isand to be scraped off seafloor into conitnents |
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what happens when two tectonic plates collide?
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form a mountain (i.e. himalayas)
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what happens when two continental plates pull apart?
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- a rift valley is formed
- mantle convection causes eruption of basalt from seafloor - a new zone of seafloor spreading is created |
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what happens when two plates slip sideways against each other?
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- rough grinding of plates builds up pressure along hte crack between them
- this crack called a fault - pressure eventually breaks, causingan earthquake |
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can a plume of hot mantle rise within a plate causing a volcano?
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yes
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what is a hot spot?
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a plume of hot mantel rising within a plate
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what do hot spot volcanos form?
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islands, as a plate moves over it, forms a chain of islands like hawaii
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without plate tectonics, what would we have?
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huge volcanoes, like on mars
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how much do plates and continents move a year?
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2 cm (2000 km in 100 million years)
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has total continental area increased or decreased?
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increased
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on account of erosion, what are valleys shaped by?
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glaciers
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on account of erosion, what are canyons carved by?
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rivers
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on account of erosion, how is sand blown?
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by wind
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what does erosion build?
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sand dunes, river deltas, sedimentary rock
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what does erosion require?
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atmosphere, large size for volcanic outgassing, moderate distance from sun, fast rotation (for wind)
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What is the fission theory?
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the moon was once part of hte earth, but separated. likely to have come out of pacific ocean basin
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What is the capture theory?
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that the moon came from elsewhere and was caught in earth's gravity
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what is the condensation theory?
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moon adn earth condensed from same nebula that formed the solar system
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what is the colliding planetesimal theory?
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that colliding earth orbiting and sun orbiting planetesimals early in their history led to their break up into moon and sun. moon condensed from this
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what is the ejected ring theory?
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that an asteroid roughly side of mars hit heart spewing debris that orbited earth in a ring and eventually came together and formed the moon
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what are three anthropogenic issues for earth?
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- nukes
- ozone hole - global warming |
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what is the mass defect of the nucleus?
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difference between mass of actual nucleons that make up nucleus and actual mass of nucleus
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what does the mass defect do when two nucleons join to make a nucleus?
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becomes energy that is released, called BINDING ENERGY
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what do massive nuclei do to gain stability?
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gain stability by breaking into smaller nuclei with release of energy
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what do smaller nuclei do to gain stability?
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join together with release of energy
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what is the maximum binding energy per nucleon?
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mass number 56, then decreases in both directions. As one result, fission of massive nuclei and fusion of less massive nuclei both release energy.
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What are types of nuclear reactions?
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fission, fusion
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what is nuclear fission?
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uncontrolled - atom bomb
controlled - nuclear power plant Releases free neutrons, create more neutrons because adding neutron to many isotopes can make them radioactive. |
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what is nuclear fusion?
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uncontrolled - hydrogen bomb
controlled - hydrogen fusion reactor (yet to work) |
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what is a chain reaction?
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each fissioned nucleus releases neutrons, which move out to fission other nuclei. THe number of neutrons can quickly increase with each series. can get if there is a critical mass of fissionable material.
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do sides of an equation have to balance with protosn and neutrons?
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yes
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what are some nuclear fission products?
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- xenon
- strontium - cesium - iodine - plutonium 239 many have long half lives and stay radioactive for a long tiem |
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coutnries with nuclear weapons?
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us, russia, england, france, PRS, tests done by India pakstan, north korea, israel, iran, libya, egypt, syria, brazil.
in past: south africa, belarus, ukraine, kazakstan |
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what is teh source of energy from sun and stars?
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nuclear fusion
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how could fusion be good energy source?
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- two isotopes of hydrogen undergo fusion
- supply of deuterium is unlimited w seawater as a big source - enormous energy released with fewer radioactive byproducts than in fission |
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how do hydrogen bombs work?
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fission-fusion-fission. fission bomb detonated near fusion fuel. gamma and xrays of fission explosion compress and heat a capsule of tritium, deuterium, or lithium deuteride starting a fusion reaction.
- neutrons emitted by this fusion can induse a final fission stage |
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How do you control H-fusion for energy?
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- temperature more be very high to bring two nuclei together (10 million degrees!)
- density must be high so enough reactions occur in short period of time - Time - nuclei must be confined up to a second or more at 10 atmospheres of pressure in order for enough reactionst o take place - radioactivity - must still liberate free neutrons which maek the walls of the reactor radioactive |
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what does increase in UV ray make more likely?
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cataracts, mutations of crops, skin cancer, immune deficiencies, dying frogs, reduction in photoplankton growth in oceans.
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is there ozone on mars?
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no
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does ozone exist on venus?
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no, chlorine in atmosphere which destroys ozone
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what causes depletion of ozone?
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(industratial) CFCs and agricultural (nitrates) chemicals
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Where does atmopshere ceom from?
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outgassing, evaporation/buclimation of gases released from rocks and ices, bombardment of comets
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how can atmospheres lose gas?
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thermal escape, bombardment, atmospheric cratering, condensation, chemical reactions (gas combines with surface materials)
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what is the greenhouse effect?
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UV and visible light comes in through atmosphere, heats up the ground, which radiates back in infrared. CO2, h20 and other "greenhouse" gases absorb some IR radiation and warm up atmosphere and surface.
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is greenhouse effect all bad?
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no! without natural, earth would be frozen
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waht is primary greenhouse effect catalyst?
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water vapor
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how much does greenhouse effect warm the earth by?
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33 degrees celcius, approximately
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how old are instrumental measurements?
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150 yrs
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how old are written historical records?
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1500 yrs
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how old are tree rings?
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12,000 years old
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how old are ice cores?
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500,000 yrs old
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how old is ocean floor sediment?
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50 million years
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how old are fossils and rocks?
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4.5 billion years
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what causes ice ages?
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within earth:
- carbon-silicate cycles - volcanic eruptions - sudden output of co2 (warming) or particulates (cooling) - mountain building (changes in atmospheric circulation) - continent ocean configuration - OUTSIDE EARTH - changes in sun (faint early sun) - variations in orbit (mostly we don't really know) |
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what are factors in long term climate change?
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sun brightening, changes in reflectivity, changes in axis tilt, changes in greenhouse gas abundance
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what are milankovich cycles?
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tilt of axis, precession, orbit shape. to explain climate variation (can't be whoel story bc these operated through history)
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what does a small axis tilt favor?
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ice age
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what does a large axis tilt favor?
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cold winters but hot summers, interglacial
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how do we know the earth was frozen 400 million years ago?
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glacial deposits on all continents, even at low latitudes, glacial deposits immediately succeeded by thick deposits of carbonate rock
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what is thought to have precipitated the snowball earth?
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something happend to reduce C02 fluxes into the atmosphere, earth ices over completely, co2 builds up to very high level until ice melts back rapidly to nothing. (global freezing alternated w global warming and rapidly rising sea levels)
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hwo does the co2 cycle control temperature?
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volcanoes put co2 in atmosphere, but bc ice covers rocks, no wa to put co2 back into rocks to make new carbonate. greenhouse co2 builds in atmosphere. melts ice and converts earth form frozen to warm. eventuall co2 recaptured in rock.
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what are the three fundamental attributes of life?
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ability to grow, ability to reproduce, ability to evolve
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does carbon based life require h20?
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yes, to perform chemical reactions
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where is evidence for early life forms?
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in rocks
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when was first eviecne of o2?
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2x10^9 yrs ago, when life emerged from oceans
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what do life on earth need to survive?
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source of eenrgy, type of atom that can build complex structures (on earth, carbon), liquid solven (on earth, water), enough time for life to appear and evolve
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what is matter in most living things on earth?
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oxygen, carbon, hydrogen, nitrogen
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where are possible origins of organic energy?
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priomordial soup, hydrothemric vents, panspermia (life arrived from space on meteorites), chemical energy from minerals
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how far back does fossil record go?
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3.5 billion years
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what are evolutionary milestones:
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4-3.5 billion years - origin of life
3.5-2 billion - prokaryotes rule! 2.7 = o2 accumulates 2.1 = first eukaryotes 1.2 = multicellular eukaryotes .54: animals .5 = life on land |
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wht are three branches of life forms?
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- bacteria
- archaea - eukarya |
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if panspermia is a true theory, where could life have formed?
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venus or mars, even! or near deep sea vents, or comets.
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how did chemistry (maybe) beget biology?
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- chemicals found on earth sparked by lighting can form complex organic molecules naturally, thus rna can form and if some of it becomes self-replicating, DNA and full, self-replicating organisms.
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what are characteristics of prokaryotes?
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bacteria and archaea, no cell structure, no membraine, no nucleus, circular chromosome, contains DNA and protein, in every environment. photosynthesize.
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how did o2 get into environment.
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single cell organisms in oceans made, got absorbed in rocks nad finally rocks got saturated and it was released into atmosphere.
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oxygen timeline?
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2.7-2billion - accumulated in oceans
2 bya: risein atmospheric oxygen oxidizes continental iron deposits, first eukaryotes appear (coincidence?) 1bya: rise of free oxygen in oceans and atmospheres |
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when did first plants appear?
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475 million years ago
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why did the cambrian explosion happen/
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more oxygen than before, evolution of genetic complexiity (more variations), climate change (maybe snowball phase ended), asence of efficient predators
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what are types of mutations ?
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some make creature more fit, some are lethal due to copying errors or external factors.
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what are traces of asteroids?
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iridium deposits in distinct layers, othertrace elements, shocked quartz, soot deposits, impact crater 200 km off Yucatan Peninsula
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how were dinos offed?
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global warming plus 2 meteorites
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