Izbrane teme sodobne fizike in matematike
Some radioactive isotopes produced in massive stars and during supernovae have a sufficiently long decay time to provide information about events happening in our surroundings even millions of years ago. The spectral line of aluminum-26 is bright enough to allow its abundance in the Galaxy to be measured across different regions, while iron-60 is the most suitable choice when searching for the ejected material deposited on Earth. Such supernovae must have occurred within approximately 100 parsecs, making it possible that they had an impact on Earth. This article summarizes the results of various studies suggesting that at least three supernova explosions took place in our recent past: approximately 1.8 million years ago, around 2.5 million years ago, and 6.5–8.7 million years ago.
Nekateri radioaktivni izotopi, ki nastajajo v masivnih zvezdah ter med eksplozijami supernov, imajo dovolj dolg razpadni čas, da nam o dogodkih v naši okolici pričajo še milijone let kasneje. Spektralna črta aluminija-26 je dovolj izrazita, da se njegovo zastopanost v Galaksiji lahko meri tudi v različnih območjih, železo pa je najprimernejša izbira, ko iščemo izvrženi material supernov odložen na Zemlji. Takšne supernove so se morale zgoditi na razdalji do približno 100 pc, zato je možno, da so imele vpliv na Zemljo. Članek povzema rezultate številnih raziskav, ki nakazujejo, da so se v naši bližnji preteklosti zgodile vsaj tri eksplozije supernov: pred približno 1.8 milijoni let, pred približno 2.5 milijoni let in pred 6.5–8.7 milijoni let.