All other isotopes of aluminium are radioactive. One of the most secure of those is 26Al, by using a fifty percent-life of 717,000 decades: when it was existing coupled with stable 27Al from the interstellar medium from which the Photo voltaic System shaped (believe that to are made by stellar nucleosynthesis https://mariodvkyn.glifeblog.com/36204765/5-simple-statements-about-sheds-and-garages-explained