Page 47 - The Restless Earth Fossils

46 Fossils

end of that time the radium would apparently be unchanged and
would itself give out heat at the old rate.” Eventually, the amount
of heat given off would slowly decrease, but Rutherford calculated
that the pound of radium could keep giving off heat at about the
same rate for a thousand years.
Rutherford knew that uranium ores were so common that the
heat generated by radioactivity could account for much of the heat

Don’t Wake Up Lord Kelvin!

Joe D. Burchfield relates in his book Lord Kelvin and the Age of the
Earth that Rutherford had a chance to announce his conclusions
about the heat-generating powers of radioactive elements in 1904 at
the Royal Institution in England. He knew that his discoveries would
mean a revision in the age of the Earth. Lord Kelvin was an old man
at that time, but still carried considerable prestige among scientists,
and so Rutherford became a bit anxious when he found out that Lord
Kelvin would be in the audience. He described the experience this
way some time later:

I came into the room, which was half dark, and presently
spotted Lord Kelvin in the audience and realized that I was
in for trouble at the last part of the speech dealing with the
age of the earth, where my views conflicted with his. To my
relief, Kelvin fell fast asleep, but as I came to the important
point, I saw the old bird sit up, open an eye and cock a bale-
ful glance at me! Then a sudden inspiration came, and I said
Lord Kelvin had limited the age of the earth, provided no new
source of heat was discovered. That prophetic utterance refers
to what we are now considering tonight, radium! Behold! The
old boy beamed upon me.

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