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SUPERNOVA IN [#53 The Q And The Gray] |
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In [The Q And The Gray], the Voyager crew, to their delight, witness several supernovae. Supernova explosions are rare; perhaps one occurs in a typical galaxy every century. They later discover that the unusual frequency of these supernovae is not coincidence, but results from the civil war raging within the Q Continuum.
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| the Voyager crew witness a supernova, [#53 The Q And The Gray] |
A supernova is the grand-daddy of all stellar explosions. A star undergoing a supernova explosion will increase in brightness by a factor of billions. When a star explodes in a supernova, it radiates more energy in its first few seconds than that of every star in our galaxy and in the universe combined. Over the course of the next several days, the supernova's energy output can equal the energy output of ten billion stars.
Astronomers recognise two distinct types of supernovae. In
a Type I supernova, a white dwarf (a small, dense, and very old
star, rich in the element carbon) accumulates mass from an
orbiting companion star, typically a red or blue giant. Eventually
the white dwarf cannot support the weight of all that extra
mass, and it collapses in a catastrophic implosion. The core of
the white dwarf is heated to a temperature sufficient to rapidly
fuse the carbon atoms there into nickel, cobalt, and iron, resulting in a massive explosion of energy.
A Type II supernova occurs at the end of the life of a star at
least eight times as massive as the Sun. The process of nuclear
fusion has nearly run its course. Most of the lighter elements
within the star's core have fused into iron atoms. The core of the
star is essentially an iron cinder. Iron atoms cannot fuse into
heavier elements under the conditions that normally prevail
within a star's core; iron is thus the end product of stellar nucleosynthesis, the process that creates heavier elements out of
lighter constituents. When the mass of the iron core exceeds 1.4
times the mass of our Sun, the core's internal pressure can no
longer support its weight. The core suddenly collapses: in less
than one second, all of the electrons and protons in the core
merge into neutrons. The outer layers of the star fall onto the
solid neutron core and rebound outward in an immense shockwave effect that produces the supernova explosion.
dying star, Keyhole Nebula, Eta Carinae, which will explode one day soon, perhaps in our lifetime
If either type of supernova happened in our neck of the
Milky Way (that is, within a few dozen or so light-years from the
Sun) the consequences could be devastating. Gamma radiation
from the stellar explosion would be so intense that most life on
Earth would be at risk of extinction. In addition, the Earth's
ozone layer, which protects our planet from damaging ultraviolet light from the Sun, would almost certainly be destroyed by
the radiation from a nearby supernova. Fortunately, there are no local stars massive enough to explode in a supernova.
supernova 1987a
Supernova remnant in [#56 Alter Ego]
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