Radioactive Nuclides by Half-Life

Nuclide
Half-Life
(years)
Found
in Nature?
50V
6.0x1015
yes
144Nd
2.4x1015
yes
174Hf
2.0x1015
yes
192Pt
1x1015
yes
115In
6.0x1014
yes
152Gd
1.08x1014
yes
123Te
1.2x1013
yes
190Pt
6.9x1011
yes
138La
1.12x1011
yes
147Sm
1.06x1011
yes
87Rb
4.88x1010
yes
187Re
4.3x1010
yes
176Lu
3.5x1010
yes
232Th
1.40x1010
yes
238U
4.47x109
yes
40K
1.25x109
yes
235U
7.04x810
yes
244Pu
8.2x107
yes
146Sm
7.0x107
no
205Pb
3.0x107
no
236U
2.39x107
yes-P
129I
1.7x107
yes-P
247Cm
1.60x107
no
182Hf
9.0x106
no
107Pd
7x106
no
53Mn
3.7x106
yes-P
135Cs
3.0x106
no
97Tc
2.6x106
no
237Np
2.14x106
yes-P
150Gd
2.1x106
no
10Be
1.6x106
yes-P
93Zr
1.5.0x106
no
98Tc
1.5x106
no
153Dy
1x106
no

This table of radioactive nuclides sorted by their half-lives is taken from Miller, who uses it to point out that only those radionuclides with half-lives greater than 80 million years are found in nature. The exceptions are those marked with "Yes-P" indicating that they are being produced in nature, but would otherwise be missing. The point of Miller's use was to make the case that the Earth is more than 80 million years old since all isotopes with shorter halflives are no longer found in nature. It is also evident that the Earth is not infinitely old because all the radioactive series would have decay. There are various ways of modeling the age of the Earth, and the values center around 4.5 billion years.

Beryllium-10 is found because it is continually produced by cosmic ray bombardment of the upper atmosphere. So very small amounts of this isotope are found in rainfall and sediment. Neptunium-237 is produced by cosmic ray bombardment of the moon. There are other short half-life isotopes found on the Earth from the natural radioactive series.

Note: Information about isotopes may be found in tables linked to the


Periodic table
. Take the link to "Nuclear data" at the bottom of the display for any element.

Modeling the age of the Earth
Index

Nuclear Tables

Reference
Miller
Ch 3
 
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