Editing Max Planck (section)

=== Nazi dictatorship and the Second World War ===
When the Nazis came to power in 1933, Planck was 74 years old. He witnessed many Jewish friends and colleagues expelled from their positions and humiliated, and hundreds of scientists emigrate from [[Nazi Germany]]. Again he tried to "persevere and continue working" and asked scientists who were considering emigration to remain in Germany. Nevertheless, he did help his nephew, the economist [[Hermann Kranold]], to emigrate to [[London]] after his arrest.<ref name="IJ">{{cite web|title=Johanna Kranold Stein|url=http://www.legacy.com/obituaries/theithacajournal/obituary.aspx?n=johanna-kranold-stein&pid=87920213|website=Ithaca Journal|publisher=Legacy.com|access-date=10 October 2016|archive-url=https://web.archive.org/web/20161011142403/http://www.legacy.com/obituaries/theithacajournal/obituary.aspx?n=johanna-kranold-stein&pid=87920213|archive-date=11 October 2016|url-status=live}}</ref> He hoped the crisis would abate soon and the political situation would improve.

[[Otto Hahn]] asked Planck to gather well-known German professors in order to issue a public proclamation against the treatment of Jewish professors, but Planck replied, "If you are able to gather today 30 such gentlemen, then tomorrow 150 others will come and speak against it, because they are eager to take over the positions of the others."<ref>In a slightly different translation, Hahn remembers Planck saying: "If you bring together 30 such men today, then tomorrow 150 will come to denounce them because they want to take their places." This translated quote is found in: Heilbron, 2000, p. 150. Heilbron, at the end of the paragraph, on p. 151, cites the following references to Hahn's writings: Otto Hahn ''Einige persönliche Erinnerungen an Max Planck'' MPG, ''Mitteilungen'' (1957) p. 244, and Otto Hahn ''My Life'' (Herder and Herder, 1970) p. 140.</ref> Under Planck's leadership, the [[Kaiser Wilhelm Society]] (KWG) avoided open conflict with the Nazi regime, except concerning the Jewish Fritz Haber. In May 1933 Planck requested and received an interview with the recently appointed Chancellor of Germany [[Adolf Hitler]] to discuss the issue, telling him that the "forced emigration of Jews would kill German science and Jews could be good Germans", to which the chancellor replied "but we don't have anything against the Jews, only against communists". Planck was therefore unsuccessful, since this reply "took from him every basis for further negotiation",<ref>{{cite book |last1=Clary |first1=David |title=Schrödinger in Oxford |date=2022 |page=54|bibcode=2022scox.book.....C }}</ref> as to Hitler "the Jews are all Communists, and these are my enemies." In the following year, 1934, Haber died in exile.<ref>{{Cite journal|last=O'Flaherty|first=James C.|date=1956|title=Max Planck and Adolf Hitler|url=https://www.jstor.org/stable/40222051|journal=AAUP Bulletin|volume=42|issue=3|pages=437–444|doi=10.2307/40222051|jstor=40222051|issn=0001-026X}}</ref>

One year later, Planck, having been the president of the KWG since 1930, organized in a somewhat provocative style an official commemorative meeting for Haber. He also succeeded in secretly enabling a number of Jewish scientists to continue working in institutes of the KWG for several years. In 1936, his term as president of the KWG ended, and the Nazi government pressured him to refrain from seeking another term.

As the political climate in Germany gradually became more hostile, [[Johannes Stark]], prominent exponent of the ''[[Deutsche Physik]]'' ("German Physics", also called "Aryan Physics") attacked Planck, [[Arnold Sommerfeld]], and Heisenberg for continuing to teach the theories of Einstein, calling them "white Jews". The "Hauptamt Wissenschaft" (Nazi government office for science) started an investigation of Planck's ancestry, claiming that he was "1/16 Jewish", but Planck denied it.<ref>Heilbron, 2000, [https://books.google.com/books?id=d5zKH2Bx2AwC&pg=PA191 p. 191] {{Webarchive|url=https://web.archive.org/web/20150320084452/http://books.google.com/books?id=d5zKH2Bx2AwC&pg=PA191 |date=20 March 2015 }}</ref>

In 1938, Planck celebrated his 80th birthday. The DPG held a celebration, during which the Max-Planck medal (founded as the highest medal by the DPG in 1928) was awarded to French physicist [[Louis de Broglie]]. At the end of 1938, the Prussian Academy lost its remaining independence and was taken over by Nazis, as part of their process of ''[[Gleichschaltung]]''. Planck protested by resigning his presidency. He continued to travel frequently, giving numerous public talks, such as his talk on Religion and Science and, five years later, he was sufficiently fit to climb 3,000-metre peaks in the [[Alps]].

During the [[Second World War]], the increasing number of Allied bombing missions against Berlin forced Planck and his wife to temporarily leave the city and live in the countryside. In 1942, he wrote: "In me an ardent desire has grown to persevere this crisis and live long enough to be able to witness the turning point, the beginning of a new rise." In February 1944, his home in Berlin was completely destroyed by an air raid, annihilating all his scientific records and correspondence. His rural retreat was threatened by the rapid advance of the Allied armies from both sides.

In 1944, Planck's son [[Erwin Planck|Erwin]] was arrested by the [[Gestapo]] following the attempted assassination of Hitler in the {{awrap|[[20 July plot]]}}. He was tried and sentenced to death by the [[People's Court (Germany)|People's Court]] in October 1944. Erwin was hanged at Berlin's [[Plötzensee Prison]] in January 1945. The death of his son destroyed much of Planck's will to live.<ref>{{cite web|url=http://physics.nobel.brainparad.com/max_karl_ernst_ludwig_planck.html |title=Max Karl Ernst Ludwig Planck |access-date=17 June 2010 |url-status=dead |archive-url=https://web.archive.org/web/20080512151051/http://physics.nobel.brainparad.com/max_karl_ernst_ludwig_planck.html |archive-date=12 May 2008 }}</ref>