Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: spook1456 on 16/04/2011 16:06:25

Title: Does Zr-96 have the longest half life?
Post by: spook1456 on 16/04/2011 16:06:25

name         Bec S.
status       student
age          15

Question -   Does uranium238 have the longest half life of all
radioactive elements?
-----------------
Oh my, no.  U-238's half-life is long, 4.51e9 y, but it is not the longest.
Here is a list of nuclides with longer half-lives.


V-50 6e15 y
Rb-87 5e11 y
Zr-96 >3.6e17 y
Te-123 1.2e13 y
Nd-144 5e15 y
Sm-147 1.06e11 y
Sm-148 1.2e13 y
Sm-149 4e14 y
Gd-152 1.1e14 y
Lu-176 3e10 y
Hf-174 2.0e15 y
Ta-180 >1e13 y
Re-187 7e10 y
Pt-190 6e11 y
Pt-192 1e15 y
Th-232 1.41e10 y

The longest-lived of these is Zr-96, with a half-life nearly a hundred
million times longer than U-238.

Richard E. Barrans Jr., Ph.D.
PG Research Foundation, Darien, Illinois
=====================================================
U(238) has a long half life but not THE LONGEST. Some other grandfathers are:
Th(232) t1/2 = 1.405x10^10 years, Lu(176) t1/2 = 3.78x10^10 years, Hf(174)
t1/2 = 2x10^15 years
I am not sure these are the longest, but you can scan the following web site for data in many forms:
http://ie.lbl.gov/education/isotopes.htm


Vince Calder
=====================================================

Mod Edit: Please phrase your post titles in the form of questions.

Title: Re: Does Zr-96 have the longest half life?
Post by: Kryptid on 16/04/2011 16:23:33

Last I heard, some isotope of bismuth was the longest-lived.

Title: Re: Does Zr-96 have the longest half life?
Post by: syhprum on 16/04/2011 17:35:51

Hydrogen has only one Proton and the life of Protons has been estimated at 6.6*10^33 years

http://en.wikipedia.org/wiki/Proton_decay