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Details

chapters 17 and 18
questions
15
Astronomy
12th Grade
12/16/2012

Additional Astronomy Flashcards

 


 

Cards

Term
researchers usually assume that the universe is homogeneous and isotropic. this assumption is known as the _____.
Definition
cosmological principle
Term
the difference between the idea that the night sky should be as bright as the daysky and the actual appearance of teh night sky is known as ____.
Definition
olber's paradox
Term
the stupednous, unmiaginably violent event, involving literally everyting in the cosmos is known as the ____.
Definition
big bang
Term
teh density corresponding to a universe in which gravity acting alone would be just sufficient to halt the present expansion is called the universe's _____.
Definition
critical density
Term
the universe appears to be expanding at an increasing rate
Definition
cosmic acceleration
Term
the mysterious cosmic force cuasing the universe to accelerate, it carries energy, exerts a repulsive effect on the universe and causes empty space to expand
Definition
dark energy
Term
in a high density universe, space is curved so much that it bends back on itself and closes off, making the universe finite in size. this is called a _____.
Definition
closed universe
Term
a low density , saddle curved universe that is infinite in extent
Definition
open universe
Term
the radio hiss that penzias and wilso detected
Definition
cosmic microwave background
Term
the production of elements heavier than hydrogen by nuclear fusion shortly after the big bang
Definition
primordial nucleosynthesis
Term
During _____, the universe expanded enormously.
Definition
cosmic inflation
Term
a mixture of gases is placed in the upper bulb to simulate earth's primordial atmosphere and then energized by spark discharge elctrodes to simulate lightening. after about a week, amino acids, and other complex molecules are found in the trap at the bottom which simulates the primordial oceans into which heavy molecules produced in the overlying atmosphere would have fallen
Definition
urey miller experiment
Term
of all the star systems in our milky way galaxy, progressively fewer and fewer have each of the qualities typical of a long lasting technological society
Definition
drake equation
Term
radio radiation leaks from earth into space because of the daily activities of our technological civilization
Definition
earth's radio leakage
Term
some reasearchers have proposed that the interval between 18 cm and 21 cm is the best wavelength range for civilizaitons to transmit or listen
Definition
water hole
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