Assertion: actinium's isotope | /r/CreatedBy | the s-process
Facets:
Source sentences:
text: All the elements and isotopes found on Earth, with the exceptions of hydrogen, deuterium, helium, helium-3, and perhaps trace amounts of stable lithium and beryllium isotopes which were created in the Big Bang, were created by the s-process or the r-process in stars, and for those to be today a part of the Earth, must have been created not later than 4.5 billion years ago.