In the Beginning, H

Biggest of all big questions that scientists ask is: "How did the universe originate?" At last week's Pasadena meeting of the National Academy of Sciences, two Caltech professors, Astrophysicist Jesse L. Greenstein and Physicist William A. Fowler, took issue with the "big bang" theory of the birth of the universe. According to this theory, all the matter in the universe was once concentrated in a single dense mass consisting mostly of neutrons. Some of the neutrons disintegrated, forming protons and electrons. They joined with the protons and one another, forming heavier elements. The original nuclear reactions were complete in a few minutes, and they generated so much energy that the ylem (from Greek, original matter) blew up with cosmic vigor. The pieces flew apart. They are still flying apart today as the myriad galaxies of the expanding universe.

Rival cosmologists find many things wrong with this theory. They point out, for instance, that if all the chemical elements were formed during the first "big bang," all the stars that can be observed should be made of the same mixture of elements. This is not the case. Some stars are made almost entirely of hydrogen and helium, while others contain considerable amounts of middleweight and heavy elements. These must have been formed in some way that is not accounted for in the big bang theory.

Old Stars. Drs. Greenstein and Fowler, backed by a group of British cosmologists, believe that the universe was formed gradually out of a cloud of plain hydrogen over billions of years. Old stars that condensed first from the cosmic cloud were made entirely of hydrogen; there was nothing else to be made of. As nuclear reactions took place inside them, they turned partly into helium by fusion processes similar to those that generate the energy of hydrogen bombs. They also cooked up middleweight elements such as carbon and oxygen.

Since many stars shoot part of their material back into space, the elements produced in the oldest stars became mixed in the general cloud of hydrogen. Therefore new stars that formed out of the cloud started with a different, more varied composition. The nuclear reactions inside them were different, too. They built up heavier elements and shot part of their product back into the cloud.

As his proof that this theory is not mere cosmos-dreaming, Dr. Greenstein told about a group of red giant stars that contain very heavy elements and are still producing them abundantly. Dr. Fowler traced in detail the stellar nuclear reactions that build heavy elements, step by step, out of the original hydrogen.

Young Sun. Since the earth is made mostly of middleweight and heavy elements, Dr. Greenstein believes that it and the sun (as well as the other planets) were formed fairly late in cosmic history, when the cosmic gas contained elements other than hydrogen. He thinks that the solar system may be something like a billion years younger than the universe.