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.

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