Entropy and the 2nd law of thermodynamics are “smoking gun” arguments that creationists believe prove that the Earth is young. Because they believe that entropy and the 2nd law of thermodynamics state that things run down with time, they conclude that it is therefore impossible for the universe to be billions of years old.

They are wrong because they have not understood the concepts properly.

The second law of thermodynamics (a Wikipedia link) is involved with the one-way nature of systems. For example, if a hot cup of coffee is left alone it will eventually become a cold cup of coffee. That is because heat passes from a body to a colder body and never the other way around. The 2nd law also notes that not all energy in a system can be converted into useful work because some energy is always lost or dissipated (usually as heat).

Entropy (a Wikipedia link) is a measure of how mixed up a system is. It is a measure of randomness, disorder, or unavailable energy within a system. In thermodynamics it describes how dispersed a system’s energy is. The second law of thermodynamics leads to the entropy of a system increasing as time goes on. The ultimate end of our universe involves the maximum value of entropy when all molecules have dissipated and spread out evenly in the universe (in at least 10¹⁰⁰ years, so don’t lose sleep over it).

It is possible to decrease the entropy of a local system. For example, a cup of water can be frozen. Note that the localized decrease in entropy must be accompanied by an increase of entropy in its surroundings. So in the case of freezing a cup of water, the surrounding system involves a freezer being used – which uses electricity and generates heat.

The “thinking” creationist sees this as an argument against evolution (even though it has nothing to do with evolution) because they somehow believe that in almost 5 billion years, the Earth should have wound down to be a “cold cup of coffee” by now. What they are not considering is the definition of the various types of thermodynamic systems:

• An Open system is one that exchanges both matter and energy with its surroundings.
• A Closed system is one that only exchanges energy with its surroundings.
• An Isolated system exchanges neither energy nor matter with its surroundings.

At first glance, the Earth appears like an isolated system (being surrounded by a vacuum), but of course, it isn’t. The Earth receives an enormous amount of energy from the sun each day (even on overcast days). Each hour the Earth receives about 430 quintillion Joules of energy from the sun (that’s 430 with 18 zeros after it!). In comparison, humans use about 410 quintillion Joules of energy in a year. So the sun inputs over 9,000 times the energy that humans use.

The mistake creationists make is not acknowledging that the Earth is an open system. It is an open system because it exchanges both energy and matter with its surroundings. There is energy from the sun but there is also physical matter that enters the atmosphere. It is estimated that at least 50 to 100 tons of matter enter the atmosphere each day (in the form of meteoroids and dust). Only about 15 tons of that manages to make it to the surface of the Earth.

As an extreme example, the Chicxulub asteroid impact about 66 million years ago (the one that led to the extinction of the non-avian dinosaurs), released energy equivalent to about 100 teratons of TNT, and caused the Earth’s average surface temperature to spike by roughly 5 degrees Celsius (around 9 degrees Fahrenheit). That led to a period of global warming that lasted approximately 100,000 years. Earth is most definitely not a closed (or isolated) system.

The energy incoming to the Earth is used to warm the oceans and land, and it is used by plants to perform photosynthesis. It is even caught by humans (via solar panels) to warm water and recharge cars, and the like. The point being that the Earth is more like a cup of coffee that is not allowed to turn into a cold cup of coffee because it is continually sitting on a hot plate. Of course, one day the sun will use up its fuel supply and, if it doesn’t first expand and destroy the Earth, it will go “cold” and the Earth will follow it and turn into a “cold(er) cup of coffee”. That’s not going to happen for several billion years, so again, don’t lose sleep over it.

The universe is thought to be an isolated system, and that’s because that seems like a reasonable thing to believe. We will never be able to observe the limits of the universe (if there are even limits), so we cannot state if there is something outside our universe that could cause it not to be isolated. Of course, there is the argument that if there is something outside of our universe, then it is part of our universe – depending on how you want to define “universe”. There are concepts of parallel universes (or multiverse – a Wikipedia link), which tend to blur the definition of isolated systems.

It sometimes gets weird by creationists because they are known to liken entropy to a belief that evolution can’t produce more complex life from simpler life. The concepts of evolution and entropy cannot be equated in that way, so exactly what creationists are thinking is a mystery known only to those who first lied to them?

The other mistake that creationists make is to not appreciate the scale of the systems involved. The Earth is huge. The Earth’s surface is slightly heated by its internal heat source (the molten interior), but hugely heated by the sun (see above). It simply isn’t correct to make conclusions about the Earth’s fate based on thousands of years. Instead, measurements in the billions of years have to be used.

There are even weirder beliefs by some creationists to do with the concepts of entropy and outcomes to do with the 2nd law of thermodynamics only started with the “fall of mankind” (when adam and eve supposedly went bad). The concept being that before the “fall”, things were perfect and therefore there was no decay due to things like increasing entropy. Luckily, that fairy story and beliefs flowing from it are falling into disregard, even by creationists. That’s because they have been unable to prop up their incredulous fantasies in the face of a better understanding of science by the average population.

If only the creationists, who are so willing to misunderstand physical laws – which they have spent zero time trying to understand, took the time to do some real study, we would be much closer to dragging ourselves out of the superstitious religiously-based morass in which we (unbelievably) still find ourselves in the 21st century.