Classics - Resonance

The following article written by George Gamow in 1948 describes his ideas of synthesis of elements in the epoch shortly following the Big Bang. The current understading of this process is somewhat different from what is outlined in this article. Firstly, the distance estimation by Hubble is now known to be wrong by a factor of almost ten. This revision (and the recent discovery of the existence of the cosmological constant; see Resonance, p.91, May 2004)) puts the age of the universe at approximately 14 billion years. There is therefore no contradiction with the age of the universe any longer.

Secondly, it is no longer believed that all elements are formed in the early universe. Elements heavier than beryllium, whose atomic number is 4, are difficult to fuse as there is no stable isotope with atomic weight 8 which can be formed by two helium nuclei. Heavier elements are therefore produced only in the cores of stars (with the help of a reaction involving three helium nuclei), and not during the ‘primordial nucleosynthesis’ era of the universe.

Galaxies in Flight

George Gamow

If the island universes are indeed racing away from one another, the fact may shed light on the primordial formation of nuclei and atoms.

In the year 1929 the Mount Wilson astronomer Edwin Hubble made a very remarkable discovery. He found that the giant accumulations of stars known as galaxies, which are scattered in great multitude through the vast expanses of the universe as far as the best telescopes can see, seem to be running away from one another at fabulously high speeds. From this observed fact originated the famous theory of the expanding universe. Although the theory is still not finally proved, it seeded a whole generation of fruitful study, not only in astronomy but also in geology, physics and chemistry. It gave us a new start for investigating the age of the universe and the creation of the stuff of which it is made. If our far-flung cosmos came originally from a dense hot core of material concentrated in one place, then we can reasonably assume that this tightly packed core must have consisted in the beginning of elementary building blocks, most of them probably neutrons, out of which all the chemical elements later were made. I shall discuss briefly some recent studies of this phase of the expanding-universe theory which have been made by Ralph Alpher, Hans Bethe and George Gamow. The main subject of this article, however, is the basic theory itself, and how it stands up today, 19 years after Hubble’s discovery.

Read full article ( 81 Kb)