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#11
n/a
22
Astronomy
Undergraduate 1
04/16/2013

Additional Astronomy Flashcards

 


 

Cards

Term
the latest studies from _____ led to the dyscovery of dark energy
Definition
type I supernovae at very large red shifts
Term
what temperature has the big bang cooled to by what now
Definition
just over 2.7 K
Term
the expansion rate of the universe is
Definition
increasing
Term
the concept that on the grandest of scales the universe is similar in appearance everywhere is
Definition
homogeneity
Term
the presently accepted value of the Hubble constant gives an age of
Definition
14 billion years
Term
with a hubble constant of 70KM/sec/mpc the critical density would be
Definition
9x10 -27 kg/m3
Term
if OMEGA o is less than one
Definition
the universe will expand forever
Term
the concept that the direction of obervation does not matter overall is
Definition
isotropy
Term
most of the deuterium formed right after the big bang
Definition
quickly burned into helium nuclei
Term
the darkness of the night sky in an infinite universe is addressed in
Definition
Olbers paradox
Term
how does the energy of the cosmic microwave background compare to the energy radiated by all stars and galaxies that ever existed
Definition
about ten times more from the big bang than from stars and galaxies
Term
the tiny ripples in the background radiation COBE found are due to
Definition
a gravitational redshift caused by growing dark clumps
Term
the big bang formed
Definition
hydrogen and helium but very little else
Term
the redshift of the galaxies is correctly interpreted as
Definition
space itself i expanding with time, so the photons are stretched while they travel through space
Term
homogeneity and isotropy taken as aasumptions regarding the structure and evolution of the universe are known as
Definition
the cosmological principal
Term
what key event happened during the decoupling epoch
Definition
expansion cooled the universe enough that protons could capture electrons in orbit
Term
because almost all galaxies show redshifted spectra, we know that
Definition
the universe is expanding
Term
what is the meaning of a closed universe
Definition
the universe will someday stop expanding and start to collapse
Term
the best answer to both the flatness and horizon problems is
Definition
the inflationary epoch
Term
concerning dark energy, we predict
Definition
its density remains constant over time, so it is not important in the early universe
Term
in the critical density universe now proposed, of the ratio of dark energy to matter i about
Definition
3 to 1
Term
before the decoupling
Definition
the universe was opaque to radiation
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