THE LAW OF ENTROPY (also called the Second Law of Thermodynamics)

Astronomer and physicist Sir Arthur Eddington:
“The second law of thermodynamics [law of entropy] holds, I think, the supreme position among the laws of Nature . . . if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but collapse in deepest humiliation.”
Arthur S. Eddington, The Nature of the Physical World (New York: Macmillan), 74.

The law of entropy tells us that energy in the entire universe follows a pattern called “entropy,” in other words, gradually losing energy, dissipation, breaking down, falling apart or disorder.

The intact egg on the left side represents a state of order (low entropy), the cracked eggs in the center represent increasing entropy, and the broken eggs on the right represent high entropy.

To describe “entropy” in simple terms, the universe:
• is slowly running out of usable energy,
• constantly moving toward disorder or entropy, and
• will eventually suffer “heat death” or “thermal equilibrium.”

Another example of entropy is our bodies, which are NOT perpetual motion machines that will live forever. We grow tired, lose muscle mass, move slower with time. Eventually, the energy our bodies possess will dissipate, and we will pass on.

Another example is a star, like our sun:
“At the end of a star’s life, when its reserves of nuclear fuel are exhausted, the star collapses under the force of its own weight . . . . Slowly the white dwarf radiates into space the last of its heat and fades into darkness.”
Robert Jastrow, God and the Astronomers (New York, W.W. Norton & Co., 1992), 83.

Philosopher William Lane Craig:
“And the universe, too, faces a death of its own . . . Eventually all the stars will burn out, and all matter will collapse into dead stars and black holes. There will be no light at all; there will be no heat; there will be no life; only the corpses of dead stars and galaxies, ever expanding into the endless darkness and the cold recesses of space – a universe in ruins. This is not science fiction. The entire universe marches irreversibly toward its grave.”
William Lane Craig, Reasonable Faith (Wheaton, IL: Crossway Books, 2008), 72.

CONCLUSION

At its present rate of entropy, if the universe actually extended back into the “eternal past,” IT WOULD HAVE RUN OUT OF ENERGY BY NOW!

So this fact of diminishing usable energy indicates to us that:
• The universe did NOT extend into the eternal past.
• It MUST have had a beginning!