Supernova 1994D and the Unexpected Universe
Explanation:
Far away, long ago, a star exploded.
Supernova 1994D, visible as the bright spot on the lower left,
occurred in the outskirts of disk galaxy
NGC 4526.
Supernova 1994D was not of interest for how different it was,
but rather for how similar it was to other
supernovae.
In fact, the light emitted during the
weeks after its explosion caused it to be given
the familiar designation of a
Type Ia supernova.
If all
Type 1a supernovae have the same intrinsic brightness,
then the dimmer a supernova appears, the farther away it must be.
By calibrating a precise
brightness-distance relation,
astronomers are able to estimate not only the
expansion rate of the universe (parameterized by the
Hubble Constant),
but also the
geometry of the universe we live in
(parameterized by
Omega and
Lambda).
The large number and great distances to
supernovae measured over the past few years
have been interpreted
as indicating that we live in a
previously unexpected universe.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
