Reason behind the existence of radioactive substances till now [closed]








**Closed**. This question needs [details or clarity](/help/closed-questions). It is not currently accepting answers.
 
 






---








**Want to improve this question?** Add details and clarify the problem by [editing this post](/posts/165264/edit).




Closed last year.








[Improve this question](/posts/165264/edit) 



If radioactive substances continuously radiates alpha particles, then that element would never be seen by us because it would had been converted into some stable atom a long time ago. Am I right?




You are right but the key point is your perception of "long time ago." Naturally occurring elements which are unstable, like U (Z=92) or Th (Z=90), have half lives on the order of the age of the Earth, i.e., they decay *very very* slowly. How old is the Earth by current estimates? About 4.5 billion years. So, these two elements, once they were formed at the time of the creation of this Earth (or the Sun?), are still present today. They are indeed continuously forming less stable elements, for example radon gas is formed in the decay series of U/Th. Their half-life are very short, on the order of a few days, but the gas is continuously being formed in the Earth's crust from the decay of U and Th daughters.


This is a very interesting topic. Paul Karoda, a Japanese American chemist, in the 1950s investigated all these questions which are coming to your mind and wrote a beautiful book (only 150 pages) titled "*The Origin of the Chemical Elements*"...buy it if you really think seriously about the origins of the elements on this Earth. Makes you wonder about the beauty of this universe and its Creator.


 1