Johannes Stark

German physicist

• Born: April 15, 1874; Schickenhof, Kingdom of Bavaria (now Germany)
• Died: June 21, 1957; Traunstein, West Germany (now Germany)

Stark’s detection of the Doppler effect in a terrestrially generated light source led to his discovery that a strong electric field will split the spectral lines of chemical elements. Stark’s experiments provided confirmation of Albert Einstein’s special theory of relativity and evidence for the controversial quantum theories of Max Planck.

Primary field: Physics

Specialty: Atomic and molecular physics

Early Life

Johannes Stark was born in the German town of Schickenhof. His father was a landed proprietor. The young Stark demonstrated early scholarly promise and eventually attended the gymnasiums (German secondary schools) of Bayreuth and Regensburg before entering the University of Munich in 1894. After studying chemistry, crystallography, mathematics, and physics courses for three years, he received his doctorate for a dissertation entitled “Untersuchung über Russ” (Investigations into lampblack, 1897). Stark successfully completed the state examinations required for teaching higher mathematics in 1897 and assumed the post of assistant to Eugen von Lommel of the Physical Institute at the University of Munich in October of that year. Shortly thereafter, he married Luise Uepler.

In 1900, Stark became a privatdozent (unpaid lecturer) at the University of Göttingen—the beginning of a tumultuous career in higher education that lasted until 1922. Stark did not work well with his coworkers or superiors, which led to frequent moves from one university to another. In 1906, he received an appointment at a technical institute in Hannover, where he aroused the dislike of his immediate superior, Julens Precht, who eventually had Stark transferred to Greifswald in 1907 and Aachen in 1909. In 1917, Stark returned to Greifswald as a full professor. Two years later, he took a similar position at the University of Würzburg, where he remained until 1922.

Life’s Work

Stark’s productive career spanned approximately the years 1902 to 1928. After 1920, he became increasingly involved in what might be called the racial politics of German science, a matter in which he had already become bitterly embroiled in earlier years.

Stark’s first and most important published work, Die Elektrizität in Gasen (Electricity in gases, 1902), involved electrical conduction in gases. Stark’s discoveries were based on the Doppler effect. As early as 1842, Austrian physicist Christian Johann Doppler predicted that a luminous object moving toward a stationary observer would appear to be a different color than the color the same object would appear to be if it were moving away from the observer. Doppler theorized that all stars emit neutral or white light and that their apparent colors are caused by their relative velocities toward or away from Earth.

It was not possible to detect the Doppler effect with any sources of light generated on Earth until the twentieth century, because no earthly light source could attain sufficient velocity. In his 1902 book, Stark correctly predicted that the Doppler effect might be observed in canal rays. German physicist Eugen Goldstein discovered in 1886 that by placing the cathode in a cathode ray tube so that it divided the tube into two equal parts, and by piercing the cathode with a number of holes, one could observe many brightly colored rays traveling in straight lines and entering the space behind the cathode through the holes. Goldstein named these rays Kanalstrahlen, or canal rays.

A number of twentieth-century physicists investigated canal rays, but it fell to Stark to demonstrate the Doppler effect in canal rays in an ingenious experiment that revealed the effect in the hydrogen lines. Stark proposed his experiment as proof of Albert Einstein’s 1906 theory of special relativity. Stark had founded, in 1904, the Jahrbuch der Radioaktivität und Elektronik (Yearbook of radioactivity and electronics), a scientific journal that he edited until 1913. In 1907, he became the first editor to request an article from Einstein concerning relativity. In 1907, he even proposed that his experiments furnished proof of Max Planck’s quantum theories.

He remained a champion of relativity and quantum theory until 1913, when his animosity toward Jews increased due to personal rivalries and professional jealousy; he then denounced quantum theory and the special theory of relativity and held to his criticism of these theories until his death. Despite his racism, Stark was accorded many honors. He was awarded the Baumgartner Prize by the Vienna Academy of Sciences in 1910, and in 1914 he won both the Vahlbruch Prize of the Göttingen Academy of Sciences and the Matteucci Medal of the Rome Academy. In 1919, he was honored with the Nobel Prize in Physics. Of all the recipients of the Nobel Prize, Stark was undoubtedly the most ignored by the world media and the international scientific community. In 1922, he resigned his university post in protest of what he perceived to be the growing Jewish dominance of German academic life and retired to pursue private research.

His last important scientific work, Atomstruktur und Atombindung (Atomic structure and atomic bonding), appeared in 1928. The book confirmed the anti-Semitic stand that had made him unpopular with many of his colleagues and had forced his retirement. Stark would almost certainly have remained in an obscure retirement after 1922 had circumstances not brought Adolf Hitler to power in 1933.

The Nazis brought Stark out of retirement and appointed him president of the Physikalisch-Technische Reichsanstalt (Physical-Technical Institute) on April 1, 1933. This position gave him considerable influence over appointments to academic positions in German universities and over the allocation of research funds. His enemies within the academy nevertheless prevented his election as president of the German Physics Association that year and prevented his gaining membership in the prestigious Prussian Academy the next. In June 1934, however, the Nazis appointed Stark president of the German Research Association. His two presidencies and the concurrent passage of the Nuremberg Laws allowed Stark to exercise enormous influence on the course of physics research and teaching in Germany. The Nuremberg Laws established that only “Aryans” were citizens of the Reich, and that a noncitizen could not hold a government post. Since professors were government employees, the laws gave Stark legal authority to purge the German universities of most Jewish professors. A few “non-Aryans” were able to keep their jobs, because of stipulations in the laws that noncitizen government employees who served honorably during World War I or whose fathers had died in that war could retain their posts.

After the outbreak of widespread anti-Semitic violence in Germany on the Kristallnacht in 1938, Stark was able to retire the remaining Jewish professors, supposedly for their own protection. He was never able to remove all of his opponents from their positions, but he did much to prevent the acceptance of theories presented by Jewish scientists.

Several influential German physicists were so opposed to Stark’s attacks against other scientists that Stark was obliged to retire from public life in 1939. In 1947, Stark stood trial before a Denazification court for his activities in the Third Reich and his attacks on Jewish academics. The court found him guilty and sentenced him to four years in a labor camp. Stark served the entire term despite his advanced years. He died in Traunstein on June 21, 1957.

Impact

Stark’s scientific accomplishments have been overshadowed by the ignominy of his affiliation with the Nazi government. During his early years, he exerted a considerable and positive influence on physics, although later in his life his influence was far greater and far more negative. From 1900 to 1913, he was still in the vanguard of the new physics. His championing of the theories of Einstein, Planck, and others was important to their international acceptance. His own experiments did much to validate the theoretical work of those who laid the foundations of modern physics. Even though the Stark effect is considered of comparatively little practical value by modern physicists in the analyses of complex spectra or atomic structure, it still represents a milestone in atomic research.

Unfortunately, Stark is best remembered not for his scientific accomplishments but rather for his political activities. He will be remembered most vividly as a victim of the ideology that swept his country and the world into tragedy.

Bibliography

Hoffman, Dieter. “Between Autonomy and Accommodation: The German Physical Society during the Third Reich.” Physics in Perspective 7.3 (Sept. 2005): 293–329. Print. Sketches the history of the German Physical Society from its founding in 1845 through the 1930s. Reviews the influence of Nazism on the society.

---, and Mark Walker. “The German Physical Society under National Socialism.” Physics Today 57.12 (Dec. 2004): 52–8. Print. Offers a history of the society, including Stark’s role in the organization during Hitler’s regime.

Matteo, Leone, Alessandro Paoletti, and Nadia Robotti. “A Simultaneous Discovery: The Case of Johannes Stark and Antonio Lo Surdo.” Physics in Perspective 6.3 (Sept. 2004): 271–94. Print. Describes how both scientists simultaneously discovered that hydrogen spectral lines split into components by an external electric field. A technical article, best for advanced students.