•supernova remnants
indicate that on average the event occurs about three times every century in
the Milky Way. They play a significant
role in enriching the interstellar medium with
higher mass elements. Furthermore, the
expanding shock waves from supernova explosions can trigger the formation of
new stars (http://en.wikipedia.org/wiki/Supernova ).
•In
2009, elevated levels of nitrate ions were found in Antarctic ice (جليد
القطب
الجنوبي),
which coincided (تزامنت) with
the 1006 and 1054 supernovae. Gamma rays from these supernovae could have
boosted levels of nitrogen oxides (عززت
مستويات
أكاسيد
النيتروجين), which became trapped in the ice