the closest exploding
star seen in modern times was the Supernova 1987A . It occurred in the Large Magellanic Cloud, which is a
small galaxy that orbits our own Milky Way.
Images taken by NASA's
Hubble Space Telescope were combined to make this composite of the
blast's expanding debris. Credit: NASA / ESA / P. Challis and R.
Kirshner (Harvard-Smithsonian Center for Astrophysics)
Given the incredible amounts of energy in a supernova explosion – as
much as the sun creates during its entire lifetime – another erroneous
doomsday theory is that such an explosion could happen in 2012 and harm
life on Earth. However, given the vastness of space and the long times
between supernovae, astronomers can say with certainty that there is no
threatening star close enough to hurt Earth.
Astronomers estimate that, on average, about one or two supernovae
explode each century in our galaxy. But for Earth's ozone layer to
experience damage from a supernova, the blast must occur less than 50
light-years away. All of the nearby stars capable of going supernova are
much farther than this.
Any planet with life on it near a star that goes supernova would indeed
experience problems. X- and gamma-ray radiation from the supernova
could damage the ozone layer, which protects us from harmful ultraviolet
light in the sun's rays. The less ozone there is, the more UV light
reaches the surface. At some wavelengths, just a 10 percent increase in
ground-level UV can be lethal to some organisms, including phytoplankton
near the ocean surface. Because these organisms form the basis of
oxygen production on Earth and the marine food chain, any significant
disruption to them could cascade into a planet-wide problem.
Another explosive event, called a gamma-ray burst (GRB), is often
associated with supernovae. When a massive star collapses on itself --
or, less frequently, when two compact neutron stars collide -- the
result is the birth of a black hole. As matter falls toward a nascent
black hole, some of it becomes accelerated into a particle jet so
powerful that it can drill its way completely through the star before
the star's outermost layers even have begun to collapse. If one of the
jets happens to be directed toward Earth, orbiting satellites detect a
burst of highly energetic gamma rays somewhere in the sky. These bursts
occur almost daily and are so powerful that they can be seen across
billions of light-years.
download animation video which showing a model of GRB 080319B from here, which was
visible to the naked eye despite being billions of light-years away
because one jet was directed Earth's way. Gamma-ray bursts longer than
two seconds are caused by the collapse of a massive star. At the
collapsing star's center, a newborn black hole drives outward jets of
particles and gamma radiation. Credit: NASA/Swift/Cruz deWilde
i'm don't think our solar system could getout of any chalenge with the smallest supernova
what about you guys ?
share your opinion 
