A Great Mistake Has Been Made - Four Revolutions in the Earth Sciences - page 7

A Great Mistake Has Been Made
You Can't Win, and Eventually You Lose
In 1892, the queen made William Thomson a peer of the realm. He chose the name
“Kelvin,” for a small stream that wends its way near the University of Glasgow. 1
Some thirty years before, Kelvin, as we will henceforth refer to him, had come
to despise Lyell's theory, but not for any of the reasons already given. Indeed,
Kelvin operated from too lofty a perch to become embroiled in geology's interne-
cine squabbles. His objection came from a higher plane: physics.
Lyell's philosophy envisioned an eternal, unchanging Earth. To supply the en-
ergy necessary to keep the planet running, Lyell appealed to chemical reactions
in the Earth's interior. They produce heat, he said, which in turn generates elec-
trical currents, which break up the compounds produced in the reactions and start
the process over again. But Kelvin knew that such a scheme was impossible, for it
would violate the fundamental laws of nature.
The first law of thermodynamics holds that in any process, energy in the form
of heat and work is conserved. As science students once liked to joke, the first
law states: “you can't win”—you cannot get out more energy than you put in. The
second law, jointly discovered by Kelvin, can be stated in several different ways.
The simplest may be to say that heat flows spontaneously from hotter to colder
places, never the opposite. “Although mechanical energy is indestructible ,” Kelvin
said, “there is a universal tendency to its dissipation, which produces gradual aug-
mentation and diffusion of heat, cessation of motion, and exhaustion of potential
energy through the material universe.” 2 The message of the second law is “even-
tually, you lose.”
In describing geologic time as infinite and the Earth as unchanging, Lyell
claimed that the Earth is a perpetual-motion machine, one that can not only win
the energy battle but go on doing so forever. But the first and second laws prove
that such a machine is impossible. Lyell's theory “violates the principles of natural
philosophy in exactly the same manner, and to the same degree,” Kelvin wrote, “as
to believe that a clock constructed with a self-winding movement may fulfill the
expectations of its ingenious inventor by going for ever.” 3
Kelvin carried the battle to the geologists, charging in an 1868 address that “it
is quite certain that a great mistake has been made—that British popular geology