ASTR Midterm

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tenorsextets
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109768
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ASTR Midterm
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2011-10-17 21:49:21
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  1. Extraterrestrial life:
    any life that originates from outside Earth
  2. Evidence of how biology may be common in the universe
    • -Organic molecules form naturally everywhere
    • -Extremophiles
    • -Life appeared early
  3. Astrobiology:
    studying conditions that began and support life on earth, looking for other places with these conditions, and looking for evidence of life in other places.
  4. What were the two types of thinkers in ancient Greece?
    • Atomists
    • Aristotelians
  5. Atomists:
    Believed in extraterrestrial life?
    • the earth and sky are made of invisible atoms (4 kinds – earth, air, water, fire)
    • ET life: maybe
  6. Aristotelians:
    Believed in extraterrestrial life?
    • the 4 elements (maybe atoms, maybe not) make up the earth and the 5th element (quitessence) makes up the sky
    • ET life: NO
  7. Who put Aristotelian ideas into Christian thought?
    Aquinas
  8. When did Europeans begin to forget Greek ideas?
    early middle ages 500-1000 AD
  9. What was Atomism equated to and what did it cause?
    Atheism; caused it to go into decline
  10. How are Atomists and Aristotelians wrong?
    • -not 4 elements
    • -Earth isn't that special
    • -not enough evidence
  11. What makes evidence good?
    • -can be proven scientifically
    • -consistency in testing
    • -credible source
    • -testable, measurable
    • -mathematically explainable
    • -physical, tangible
  12. Theory:
    scientifically, a well-sustained explanation of some aspect of the natural world (like a model, but more thoroughly tested)
  13. Can everything be proven scienifically:
    NO (new info comes in all the time)
  14. Parallax:
    a back-and-forth motion in stars
  15. Greeks believed:
    the sun and stars orbit the earth
  16. Geocentric theory:
    was supposed to predict positions of planets, but the planets were never in their spots
  17. Data:
    facts and statistics collected together; often used as evidence
  18. The Big Bang
    moment when everything started in the universe, not an explosion, and nothing existed before it
  19. What did Edwin Hubble and Humanson do?
    used a large telescope to discover all galaxies are moving apart
  20. Hubble and Humanson's discoveries:
    • -farther away= moving faster
    • -Galaxies are not expanding
    • -some nearby exceptions are moving closer because of gravity
    • -the universe itself is expanding, meaning it was closer together in the past and must have been one point at one time
  21. 3 lightest elements:
    • -hydrogen
    • -helium
    • -lithium
  22. When were the lightest 3 elements made?
    within first 3 seconds of Big Bang
  23. How were the 3 lightest elements made?
    as soon as the universe expanded and cooled enough, protons, neutrons, and electrons combined to make these elements
  24. Where are elements 2-26 made?
    in the center of stars by fusion (byproduct is light)
  25. Where are elements heavier than iron made?
    made in supernova when they explode
  26. Stellar recycling:
    previous generation stars die and give some contents back to space to form more stars
  27. What is light?
    sometimes described as an electromagnetic wave or as particles called photons
  28. Is light important for measuring the conditions of a planet?
    YES
  29. When light behaves as a particle:
    • -called a photon
    • -has no mass
    • -only thing in universe to travel at the speed of light
    • -photons have different energies
  30. What are the light intesity names from left to right?
    • 1) Gamma
    • 2) X-ray
    • 3) Ultraviolet
    • 4) visible
    • 5) Infrared
    • 6) microwave
    • 7) Radio
  31. How is visible light different from invisible light?
    energy intensity
  32. How does one see different types of light?
    using a different telescope for the specific kind of light
  33. X-ray
    • -high energy radiation
    • -used in medicine to tell ho dense something is
  34. Infrared light (IR)
    objects that are warm or hot emit IR ratiation (heat waves); the hotter the object, the more heat waves it emits
  35. What different types of light can tell us:
    • -how far away things are in space
    • -what elements are emitted
    • -how hot the place is (temp. and radiation)
    • -density of planet
    • -speed the objects are apporaching or receding
    • -how fast they spin
  36. How can we learn about temp. from light?
    • more heat= more light emitted
    • more heat= more high energy light emitted
  37. What is radioactivity?
    the nuclei of some isotopes spontaneously break apart, relasing particles, energy, and daughter isotopes
  38. What is radioactivity also called?
    fission or radioactive decay
  39. Is radiation the same as radioactivity?
    NO
  40. What does high-energy ratiation/particles do to DNA?
    it breaks the DNA strands
  41. Does background ratiation hurt us too?
    it does penetrate DNA, but our bodies can repair it quickly
  42. How does radiometric dating work?
    rocks and fossils get less radioactive over time; this is what is used to tell the ages
  43. Half-life:
    time it takes for an element to decay to exactly half of the origional sample
  44. Why is the earth still warm?
    • -impacts
    • -differentiation (dense stuff sinks to the bottom)
    • -radioactivity
  45. Aesthenosphere:
    flowy, gooey part between crust and mantle
  46. Earth's layers from inside to outside:
    • 1) inner core (solid metal)
    • 2) outer core (liquid)
    • 3) mantle (solid)
    • 4) crust
  47. What creates Earth's magnetic field?
    the core's convection cells
  48. How does the Earth's core create magnetic fields?
    the core convection moving around the charged particles creates a magnetic field that shields the atmosphere
  49. How does the magnetic field protect us on Earth?
    it prevents solar wind from stripping away the atmosphere
  50. What two conditions are needed for water?
    • -correct temperature
    • -correct pressure (needed for liquid form)
  51. What drives plate tectonics?
    convection in the aesthenosphere
  52. How does CO2 enter and leave the earth's atmosphere?
    plate tectonics
  53. What effect do greenhouse gases have on Earth's temperature?
    the more greenhouse gases, the hotter Earth gets
  54. What is the most abundant greenhouse gas?
    water vapor (H2O)
  55. 6 classifications of life:
    • complex and organized
    • reproduces
    • grows and develops
    • taking and using energy
    • responds to environment
    • evolution and adaptation
  56. Is evolution linear?
    NO
  57. Basic unit of life:
    Cell
  58. All living things have:
    cells, DNA, protein
  59. Main elements of cells:
    sulfur, carbon, hydrogen, nitrogen, oxygen, phosphorus (SCHNOPs)
  60. What is the most common element in the universe?
    hydrogen
  61. What are the major molecules?
    • -Protein
    • -Lipid
    • -Nucleic Acid
    • -Cabohydrates
  62. Protein:
    workhorses of cells; enzymes, antibodies, hormones
  63. Lipids:
    fats, oils, cholesterol; long term energy storage, cell structure, and hormones
  64. Nucleic Acids:
    DNA and RNA; info storage and transfer
  65. Carbohydrates:
    sugar and polysaccharides; short-term energy storage
  66. Why is carbon a better element for life than others?
    • -very abundant
    • -can bond up to 4 other elements at a time
    • -very strong bonds
    • -can make double bonds with itself
  67. What does RNA need to make DNA?
    protein
  68. What major molecule determines how we look and how we function?
    protein
  69. Earth life needs 3 things:
    • -source of carbon and other raw materials
    • -source of energy
    • -water (liquids)
  70. Abiogenesis:
    "life arising from non-life"
  71. What are some problems with abiogenesis?
    • -biologists use this model knowing it's incomplete
    • -not all steps are reproducible in the lab
  72. Where did life most likely begin?
    deep-sea vents
  73. Five steps in development of life:
    • 1) molecular building blocks form
    • 2) RNA becomes self-replicating
    • 3) pre-cells arise
    • 4) true cells with RNA genomes appear
    • 5) modern cells with DNA genomes evolve
  74. Which came first: DNA or RNA?
    RNA came first and may have assembled itself by sticking to rock or clay or assembled in icy water
  75. Can nucleic acids be made in the lab?
    NO
  76. What does RNA need to replicate itself?
    replicase
  77. Which is better: DNA or RNA?
    DNA; stonger, copies more reliable, encode more.
  78. What are comets?
    icy asteroids that were formed in the colder regions of the solar nebulas
  79. What is a comet's tail?
    ice being subliminated to gas by the sun's heat
  80. Meteor:
    shooting star
  81. Meteorite:
    meteor that hit the ground
  82. Comets live forever?
    NO
  83. What causes meteor showers?
    residue from comets
  84. What was the K-T impact?
    the huge meteorite that hit the earth 65 mil. years ago and caused the extiction of the dinosaurs by climate change
  85. 5 major mass extinctions:
    • Impacts: 2
    • Volcanism and global warming: 1
    • Poisoning: 1
    • Sea level change: 1
  86. 8 pieces of evolution:
    • appendix
    • body hair
    • tailbone
    • extra ribs
    • goosebumps
    • male nipples
    • third eyelid
    • wisdom teeth
  87. What was the appendix for?
    ancestors needed extra organ to digest tough veggies
  88. What were the wisdom teeth for?
    ancestors had bigger mouths and used them for grinding tough plants
  89. What was the tailbone for?
    ancestors had tails and the modern tailbone is several tiny fused bones

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