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The Birth and Death of the Sun by George Gamow provides answers to some of the most difficult questions humanity has ever had. What led to the Sun’s existence? How is it able to remain hot and luminous? Is it heading to extinction or not? The renowned physicist and cosmologist highlight key discoveries and theories of modern physics in a non-technical yet scientific language for easy understanding. He discusses numerous topics such as the nature of red and white dwarfs, the formation of stars, the infinity of space, stellar system, and many other amusing topics that would for ages come to be brainteasers to human imagination.
The title itself is enough to make you want to read more. Most scientists are often concerned about the origin of the Sun, but rarely do they look into its extinction. Thus, when George Gamow handled it in The Birth and Death of the Sun, it caught the attention of most of his contemporaries. The professor uses a simple language to highlight key discoveries and theories of modern physics that shed more light on the world’s evolution. This is a fundamental scholarly book rich in astronomical knowledge that stimulates one’s imagination to the utmost satisfaction.
The book continues to enjoy positive reviews ever since it was first published in 1940. Gerald F.W. Mulders wrote that it has authentic information presented in a non-technical language. He continued to express his fascination with the author’s ability to eliminate mathematical formulae and incorporate sparkling humor in a physics book. Steven Weinberg rated it as one of his 13 best science books.
The positive acclaim with which the book was received is understandable. It explores atomic chemistry, stellar evolution, and cosmology, topics that humanity has always grappled with since the dawn of civilization. Gamow’s illustrations are equally something worth mentioning. The graphical illustrations are enough to create the right mental picture of what the writer needs the reader to know.
The mysterious sun
George Gamow begins his book by posing a simple question. “Which is more important, the Sun or the Moon?” Interestingly, this is a question children and even grownups often play with. The author reflects on the answer to this question that also worried a Russian philosopher, Kuzma Prutkov. According to the philosopher, the Moon is more useful since it provides us with light at night when darkness is dominant. The Sun only provides it during the daytime when there is light anyway.
This answer is sure to get you laughing. Of course, every scholar is aware that the moon shines at night because it reflects light from the Sun. But Gamow is concerned with more than just that. As he acknowledges the Sun as the major source of energy on Earth, he is interested to see where the Sun gets energy from. More interestingly, is it possible that all energy exploited by civilization originated from the solar system? The author seems to believe so, given that almost every source of energy seems to link back to the solar.
To clarify his position, George Gamow gives a couple of examples. For instance, most people burn wood, oil, or coal for energy. From a layman’s perspective, one could be deceived into thinking that these are the sources of energy, but that’s not the case. When they burn, we liberate the energy deposited by the Sun in the form of carbon compounds. He goes on to explain how this energy ends up in the trees. The Sunrays that fall on green leaves in the presence of carbon dioxide decompose to carbon and oxygen gas. The oxygen is released back to the atmosphere, whereas carbon is deposited in the plant’s wood. This would yield energy when the tree is burnt. One thing worth noting is that a tree cannot yield more energy than it received from solar rays. This shows that had it not been for sunlight, there would never be trees, coal, and oil deposits.
The Sun’s massive temperatures
How hot is the Sun’s surface that it can yield such vast amounts of energy? The author gives several examples which he uses to compare with the Sun’s surface radiation. He makes calculations, which are not shown in the book. He concludes that the Sun’s surface must be around 6000 degrees C. The estimated temperature is higher compared to those obtained under laboratory conditions using specifically constructed electric furnaces. That’s because, at 6000 degrees Celsius, all the materials used to make the furnaces would be evaporated.
Even though the author does not get into calculating the Sun’s inner temperature, his estimates of the outer temperature are accurate. Modern calculations show that the Sun’s surface could be about 5,500 degrees C. The core, where nuclear fusion takes place, is estimated to be 15 million degrees C. Nuclear fusion involve compressing hydrogen atoms under high pressure to create helium. It results in high energy yield and is the reason why the Sun is hot.
The age of the Sun
The origin of the Sun, a star projected to turn into a red giant star in a few billion years, is closely associated with the Earth’s origin and the whole universe age. According to the Big Bang Theory, the universe started as a hot, small, and dense super-force referred to as a singularity. The actual formation of the universe, which includes the Sun, started 13.8 billion years ago when space started to expand. The expansion formed atoms that would, later on, become stars and galaxies.
George Gamow attempts to breakdown his version of the Sun’s age. He does not give an explicit age as modern theories do. However, he gives as to how old it could be. His arguments are closely tied to those made by the Big Bang Theory, an indication that the theory could be right after all.
Gamow holds that the same Sun that we see today is the same one that was seen centuries ago. It is the same that Napoleon observed, and the Egyptians worshipped as one of their gods. He goes on to point out that life on Earth is younger than the Earth itself. Different investigations done up to the point of the book’s writing placed the Earth’s crust to be 1.6 billion years. He explains that the formation of the crust must have taken place sooner after the Earth’s separation from the Sun. For that reason, the Sun is older than the given date. He goes on to describe a formula that compares stellar systems to another. This comparison shows that the Sun and other stars were formed not less than 2 billion years ago.
Red giants and the Sun’s fate
George Gamow describes red giants as stars of extremely large dimensions and very low surface temperatures. He cites Capella as one of such stars. This is a star that most night sky viewers know pretty well. Different telescopic observations reveal that the Capella represents a double-star system in which case its two components revolve around each other. Capella A and B temperatures are equivalent to the Sun’s temperature. Capella B is the hottest of the two (approximating 5,700 degrees C), while Capella A’s temperature is approximated at 4900 degrees C.
As much as the inner temperatures of red giants are high compared to the surface temperatures, they are still low in comparison to our Sun’s temperatures. Taking Capella as an example, it has a central temperature of 5 million degrees, which is far much lower than the solar temp of 20 million. Aurigae, another red star, is just 1.2 million degrees at its center.
Of course, these red giants are still very hot. However, they can only support a few thermo-nuclear reactions at the given conditions. The author explains that Bethe’s carbon-nitrogen cycle would be unable to go on at such temperatures. It is responsible for supplying the Sun and other stars with energy. Today is known as the CNO cycle, what the author refers to as Bethe’s carbon-nitrogen cycle is a set of fusion reactions which stars use to turn hydrogen into helium. Four protons normally fuse during this cycle. Carbon, Nitrogen, and Oxygen are catalysts of the whole process.
It is easy to understand every point that George Gamow makes regarding the Sun and its fate. He begins by giving key details of the Sun’s origin and how it can yield energy that facilitates life on Earth. The fact that his estimates of the Sun’s age are in line with the age of the Earth as estimated by most theories makes the book’s arguments credible.
The book holds that the Sun is on the verge of dying. That is, it would reach a point where it can no longer facilitate nuclear reactions, making it impossible to yield energy. At that point, it will have turned into a red giant star capable of engulfing the Earth.
Do not be frightened yet. Even though the author does not give explicit timelines as to when that is likely to happen, modern scientists believe it will take place 4-5 billion years from now. If you are wondering what you can do about it, there is no way around this. The best option is to enjoy Earth’s life as facilitated by energy from the Sun.