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Discovery of a supernova explosion at half the age of the Universe
Ist Teil von
Nature (London), 1998-01, Vol.391 (6662), p.51-54
Ort / Verlag
London: Nature Publishing
Erscheinungsjahr
1998
Quelle
EBSCOhost Psychology and Behavioral Sciences Collection
Beschreibungen/Notizen
The ultimate fate of the Universe, infinite expansion or a big crunch,
can be determined by using the redshifts and distances of very distant supernovae
to monitor changes in the expansion rate. We can now find large
numbers of these distant supernovae, and measure their redshifts and apparent
brightnesses; moreover, recent studies of nearby type Ia supernovae have shown
how to determine their intrinsic luminosities-and
therefore with their apparent brightnesses obtain their distances. The >50
distant supernovae discovered so far provide a record of changes in the expansion
rate over the past several billion years. However, it
is necessary to extend this expansion history still farther away (hence further
back in time) in order to begin to distinguish the causes of the expansion-rate
changes-such as the slowing caused by the gravitational attraction of
the Universe's mass density, and the possibly counteracting effect of the
cosmological constant. Here we report the most distant spectroscopically
confirmed supernova. Spectra and photometry from the largest telescopes on
the ground and in space show that this ancient supernova is strikingly similar
to nearby, recent type Ia supernovae. When combined with previous measurements
of nearer supernovae,, these new measurements
suggest that we may live in a low-mass-density universe.