John Carlos Baez @johncarlosbaez@mathstodon.xyz
Public

In 1934, Fermi started trying to produce "transuranics" - elements above uranium - by firing neutron beams at uranium. Meitner got excited about this and began doing the same with Hahn and another chemist, Fritz Strassman. They seemed to be succeeding, but the results were bizarre: the new elements seemed to decay in many different ways! Their chemical properties were curiously variable as well. And the more experiments the team did, the stranger their results got.

No doubt this is part of why Meitner took so long to flee Germany. Another reason was her difficulty in finding a job. For a while she was protected somewhat by her Austrian citizenship, but that ended in 1938 when Hitler annexed Austria. After many difficulties, she found an academic position in Stockholm and managed to sneak out of Germany using a no-longer-valid Austria passport.

She was now 60. She had been the head of a laboratory in Berlin, constantly discussing physics with all the top scientists. Now she was in a country where she couldn't speak the language. She was given a small room to use a lab, but essentially no equipment, and no assistants. She started making her own equipment.

Hahn continued work with Strassman in Berlin, and Meitner attempted to collaborate from afar, but Hahn stopped citing her contributions, for fear of the Nazis and their hatred of "decadent Jewish scence". Meitner complained about this to him. He accused her of being unsympathetic to *his* plight.

(5/n)

Lise Meitner, looking thoughtful, in front of a window.
John Carlos Baez @johncarlosbaez@mathstodon.xyz
Public

Given Lise Meitner's very tough situation, and Hahn's complaints to her, it's no surprise that she wrote to him:

"Perhaps you cannot fully appreciate how unhappy it makes me to realize that you always think I am unfair and embittered, and that you also say so to other people. If you think it over, it cannot be difficult to understand what it means to me that I have none of my scientific equipment. For me that is much harder than everything else. But I am really not embittered - it is just that I see no real purpose in my life at the moment and I am very lonely...."

What *is* a surprise is that this is when she made her greatest discovery.

She couldn't bear spending the Christmas of 1938 alone, so she visited a friend in a small seaside village, and so did her nephew Otto Frisch, who was also an excellent physicist. They began talking about physics. According to letters from Hahn and Strassman, one of the "transuranics" was acting a lot like barium.

Talking over the problem, Meitner and Frisch realized what was going on: the neutrons were making uranium nuclei split into a variety of much lighter elements!

In short: fission.

(6/n)

An older Lise Meitner in a white lab coat sitting in front of her desk, turning toward the camera.
0
0
0

If you have a fediverse account, you can quote this note from your own instance. Search https://mathstodon.xyz/users/johncarlosbaez/statuses/115490788701067261 on your instance and quote it. (Note that quoting is not supported in Mastodon.)