Ben Carson claimed that prevailing theories of how the universe began and how planets and stars formed violate the second law of thermodynamics. His comments represent a misunderstanding of scientific concepts.
Carson, a retired pediatric neurosurgeon and Republican presidential candidate, spoke at a rally on Sept. 22 at Cedarville University — an Ohio school that describes itself as a “Christ-centered, Baptist institution.” Carson began his discussion of science by explaining — correctly — that many studies have debunked the notion that vaccines cause autism. “That’s why we have science and scientific studies to look at these kinds of things,” he said.
He then went on to say “science is not always correct,” and claimed that the Big Bang theory is one such example (at the 1:03:13 mark):
Carson, Sept. 22: Now you’re saying, there’s a Big Bang, a big explosion, and our solar system and our universe come into perfect alignment. Now I said you also believe in the second law of thermodynamics, entropy, right? “Yeah.” And I said, that states that things move toward a state of disorganization, right? “Yeah.” I said, so, how is there a Big Bang and instead of things moving toward disorganization they become perfectly organized to the point where we can predict 70 years hence when a comet is coming. How does that work? “Well. We don’t understand everything.”
According to the Big Bang theory, that initial explosion represents the birth of the universe, about 13.8 billion years ago. The solar system that houses the Earth was born about 5 billion years ago.
Carson talked about entropy, which is commonly thought of as a measure of order or disorder; increasing entropy essentially means an increasingly disordered state. The second law of thermodynamics says that in any isolated system, the entropy of that system will increase or remain the same — not decrease.
Carson claims that the Big Bang theory violates the second law of thermodynamics, since the solar system has moved to what he calls a “perfectly organized” point, instead of becoming more disorganized.
But the two concepts aren’t in contradiction. A small part of a system can become more ordered, while the rest of the system sees a decrease in order in the process.
One good example of this is an ice tray in a freezer. The molecules in liquid water move into a more ordered state when they freeze into a solid. On its own then, water turning to ice appears to be a violation of the second law. But the ice in the freezer is not a closed system: The freezer also generates heat as it runs, which is radiated out into your kitchen. That heat increases entropy more than the water turning to ice decreases it.
Brian Greene, a physicist at Columbia University and author of several popular science books, gave us another easy-to-visualize example during a phone interview: the act of cleaning up a messy room.
Greene, Sept. 23: How do you take a messy room and make it ordered? That would seem to be decreasing the disorder – it was a mess, now it’s not a mess. It was disordered, now it’s ordered. How could anybody do that? It seems to violate the second law of thermodynamics!
But the answer is: you have to take into account all of the sources of order and disorder, including the body of the human who is cleaning up the room, the heat that they are generating, the fat that’s being burned as they undertake this exercise. And when you take into account everything – the molecules of air that get excited by the sweat forming on the brow of the individual doing the cleaning – when you take into account all of these features, the amount of disorder generated overly compensates – always – for the amount of order that’s being created in the room.
Moving outward to the solar system scale, the situation is the same. The increasing entropy is not violated by the formation of planets, stars and comets due to arrive in 70 years. All the factors that go into the formation of these celestial bodies work to increase disorder rather than decrease it. As Greene told us: “The formation of a star is an entropically increasing phenomenon. It is not decreasing the amount of disorder, it is increasing the amount of disorder, even though it looks so darn ordered relative to, say, the swirling gas cloud from which it emerged.”
Planets and stars form when gases and dust in space slow down and begin to clump together, at which point gravity helps pull these clumps together and draw in more dust and gas, until those big objects are formed. “That process as we understand it is completely consistent with the second law of thermodynamics,” Greene said.
From a universe-wide perspective, the overall increasing entropy is measurable based on the leftover heat from the Big Bang, known as the cosmic microwave background radiation. According to the Big Bang theory, at the point of the initial explosion all the energy in the universe was concentrated in a state of very low entropy — an almost completely ordered state. Ever since that explosion, that energy has been spreading out, a continually rising degree of disorder. The observed level of the background radiation is consistent with the predictions of modern cosmology. In short, Big Bang theory predicts the existence of and the specific amounts of background radiation as a result of the rising entropy of the entire system, and observations actually bear that out. “The calculations agree with the observations to fantastic precision,” Greene said.
Carson went on to claim that the presence of stars and planets is related to the existence of multiple Big Bangs that eventually might produce an ordered universe:
Carson: And then they go to the probability theory, and they say “but if there’s enough big bangs over a long enough period of time, one of them will be the perfect big bang and everything will be perfectly organized.” And I said, so you’re telling me if I blow a hurricane through a junkyard enough times over a long enough period of time after one of them there will be a 747 fully formed and ready to fly?
That is not an accurate reflection of the Big Bang theory. Though some theories of the origin of the universe suggest that the Big Bang was only one of many such explosions, these theories do not state that the currently ordered existence is a spontaneous result of one of these repeated Big Bangs. Greene called this a “red herring,” and said the concept of multiple Big Bangs has nothing to do with how stars and planets form in this current universe. Instead, those theories involve the idea that the universe goes through cycles over many billions of years: Big Bang, expansion, contraction, “Big Crunch,” followed by another Big Bang. How the stars and planets form between each of those bangs and crunches is a separate issue.
Although there is still much to be learned about the origins of the universe, the fact is science has extremely thorough explanations for how planets and stars form, and they mesh perfectly with the laws of thermodynamics.
Editor’s Note: SciCheck is made possible by a grant from the Stanton Foundation.
– Dave Levitan