Ernest Rutherford--Father of Atomic Physics and Discoverer of Nuclear Fusion

It has been said that Ernest Rutherford “is to the atom what Darwin is to evolution, Newton to mechanics, Faraday to electricity and Einstein to relativity.” 

Born in rural New Zealand in 1871, Rutherford studied there, and then at Cambridge University in England, before taking a professorship at McGill University in Montreal 

Working at McGill during 1902 and 1903, Rutherford and his colleague Frederick Soddy wrote two landmark papers proposing that radioactive decay involves the transformation of one element into another. When Soddy first realized this, he is said to have exclaimed “This is transmutation!” Rutherford immediately replied, “Soddy, don’t call it transmutation. They’ll have our heads off as alchemists!” 

In their 1902 papers on “The Cause and Nature of Radioactivity,” Rutherford and Soddy were careful to use other terms such as “radioactive change” or “transformation.”

Henri Becquerel had discovered radioactivity in 1896. Marie and Pierre Curie discovered two radioactive elements they named “radium” and “polonium” in 1898. But it took Rutherford and Soddy’s work to convince other scientists that radioactivity involves transmutation.

Rutherford moved back to England in 1907. He first worked at the University of Manchester, and then became director of the prestigious Cavendish laboratory at Cambridge University. 

Rutherford is credited with describing the structure of the atom (a tiny, dense nucleus mostly surrounded by “empty space”), with the first “splitting” of the atom, and with the “discovery” of the proton. In his 1919 paper, “Collision of Alpha Particles with Light Atoms: An Anomalous Effect in Nitrogen,” Rutherford showed that an alpha particle can split a proton from the nucleus of a nitrogen atom. He demonstrated that atoms can be split, and that protons exist.

Here's the reaction from the experiment described in Rutherford's 1919 paper:

⁴He₂ +¹⁴N₇  -> [¹⁸F₉] - p  -> ¹⁷O₈

The alpha particles (helium-4 nuclei) used by Rutherford came from “radium-C” (actually bismuth-214, a radium decay product). He detected protons from the light flashes they made when striking a zinc sulphide scintillation screen. His experimental design excluded the possibility that the flashes were made by alpha particles hitting the screen.

Rutherford did not realize it at the time, but this experiment represented the first laboratory demonstration of nuclear fusion--the combination of helium-4 and nitrogen-14 to produce oxygen-17. Other scientists quickly interpreted the research findings from his laboratory to mean that nuclear fusion could be a source of energy.  

For example, in the following year the astronomer Arthur Eddington, in his famous lecture called “The Internal Constitution of the Stars,” said

“I think that the suspicion has been generally entertained that the stars are the crucibles in which the lighter atoms which abound in the nebulae are compounded into more complex elements.”

He then asked, “is it possible to admit that such a transmutation is occurring?” 

Eddington answered his own question by citing Rutherford’s work: “what is possible in the Cavendish laboratory may not be too difficult in the sun.” Eddington calculated the immense energy that would be yielded by the combination of four protons (hydrogen nuclei) into a helium nucleus (an alpha particle).

He also issued the following prescient warning: 

“If, indeed, the sub-atomic energy in the stars is being freely used to maintain their great furnaces, it seems to bring a little nearer to fulfilment our dream of controlling this latent power for the well-being of the human race—or for its suicide.“

Unfortunately, by ignoring renewable technologies that employ the Sun’s fusion energy, and focusing instead on the energy released by fission of uranium and plutonium, the human race is nearing the nightmare of suicide, rather than the dream of well-being.

When I asked AI “Who discovered fusion?” it responded that “Nuclear fusion was not discovered by a single person. The concept evolved…” 

To explain the results of his 1919 experiment, Rutherford proposed (wrongly) that the nitrogen nucleus contains six tightly packed protons, plus a seventh proton that is less tightly bound. He suggested that collision of alpha particles with nitrogen atoms knocks off this outlying proton. The scintillation apparatus he used to detect protons gave no information about the fate of the alpha particles. They would presumably be deflected by the collision.

In 1925, Patrick Blackett, a research student working in Rutherford’s Cavendish laboratory, used a cloud chamber to more fully investigate the collision of alpha particles with nitrogen. In his paper, “The Ejection of Protons from Nitrogen Nuclei, Photographed by the Wilson Method,” Blackett says “I wish to express my thanks to Sir Ernest Rutherford, who suggested this work and assisted by his help and advice in its execution.”  

Rutherford had abandoned his original theory. If it had been correct, an alpha particle would collide with the nitrogen nucleus, eject a proton, and continue on its way. Cloud chamber photos (the “Wilson Method”) would show three tracks: a deflected alpha particle, an ejected proton, and a recoiling nitrogen atom (detectable because the collision strips away some of its electrons, leaving a positive charge).

After taking 23,000 photographs of roughly 410,000 tracks of alpha particles travelling through nitrogen gas, Blackett interpreted eight tracks (“forks”) as representing the ejection of a proton. He described these tracks as follows:

“It was to be expected that a photograph of such an event would show an alpha-ray track branching into three. The ejected proton, the residual nucleus from which it has been ejected, and the alpha particle itself, might each have been expected to produce a track. These eight forks however branch only into two. The path of the first of the three bodies, the ejected proton, is obvious… The second of the two arms of the fork is a short track similar in appearance to the track of the nitrogen nucleus… Of a third arm to correspond to the track of the alpha particle itself after the collision there is no sign.”

Blackett concluded:

“In ejecting a proton from a nitrogen nucleus the alpha particle is therefore itself bound to the nitrogen nucleus. The resulting new nucleus must have a mass 17, and, provided no electrons are gained or lost in the process, an atomic number 8.”

He correctly suggested that the new nucleus would be an isotope of oxygen, albeit one of “rare occurrence.” Oxygen-17 makes up only 0.04% of all oxygen atoms. Scientists lacked the equipment to detect oxygen-17 in 1925, but they were familiar with the concept of “isotopes.” Soddy had received the Nobel Prize in Chemistry in 1920 for his work in this area.

Today, most scientists believe that fusion requires an artificial apparatus such as a particle accelerator, or ways to mimic the intense heat and pressure in the core of a star. They should read Blackett’s paper. The alpha particles he used came from a naturally occurring radioactive deposit of thorium, and nitrogen constitutes 80% of the Earth’s atmosphere .

This means that nuclear fusion takes place here on Earth, in nature, at low temperatures. Near a source of alpha rays (such as from rocks containing thorium or uranium), atmospheric nitrogen-14 gas can fuse with an alpha particle to produce oxygen-17. 

Such fusion reactions are very rare events. However, the reality of fusion reactions at ordinary temperatures on Earth is important in relation to the mechanisms for “biological” transmutations described in my book, “The Sun Within—Atomic Energy and Life.”

Let’s again consider Rutherford’s 1919 paper, “An Anomalous Effect in Nitrogen.” While often characterized as the “first artificial transmutation,” his experiment demonstrated a process occurring in nature. Besides “splitting” an atom, and proving the existence of protons, it led to the discovery of nuclear fusion. That’s pretty impressive for a single experiment!

Transmutation of nitrogen-14 to oxygen-17 is not pure fusion. It is fusion coupled with fission: the simultaneous absorption of an alpha particle and release of a proton. As shown in the diagram above, pure fusion would stop at fluorine-18, a radioactive form of this element with a half life of two hours. This reaction would leave no proton track in a cloud chamber.

Low-temperature fusion is a reality. Why is this not better known? Why is the mainstream scientific community so adamantly opposed to research on “cold fusion?”