Indestructible = Eternity
The scientific law about indestructibility of substance says that substance cannot be destroyed, it can just change it’s form because of E = mc² for unrelativistic particles.
Experiment: By solving the 117g of salt in 200 ml of water the saturated solution is made. After the vaporization of the water the amount of salt remains the same.
Since we are also a substance = energy, we are indestructible too.
Observers were invited to do this experiment.