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2019年5月7日星期二

搜尋希特拉失落的鈾方體

搜尋希特拉失落的鈾方體
The Search for Hitler’s Lost Cubes of Uranium

May 7, 2019


“Taken from the reactor that Hitler tried to build. Gift of Ninninger.”
If, in 1946, you received a cloth bag containing a small, heavy cube with a piece of paper containing those words, would you believe it? What about if you received it in 2013? The man who received this as a gift (what kind of strange friends does he have?) in 2013 did, but it’s taken him until now to confirm it. In the process, he began a hunt for the more than 600 (and possibly 1000) other cubes of uranium that German scientists used in their attempt to build a nuclear reactor before their counterparts in the Manhattan Project did, and discovered the real reason why Hitler’s team lost the atomic race.
“I just immediately knew what this thing was.”
In an interview with Science News to announce the publication of his findings in the current edition of Physics Today, Timothy Koeth, an associate research professor in the department of materials science and engineering at the University of Maryland, describes looking at the five pound, 5 cm (2 inch) cube he received, recognizing immediately that it was a uranium cube and knowing enough about atomic history to suspect it was a cube from Hitler’s reactor because the pockmarks on its surface dated it to an early form of processed uranium. That age also told him that it was now safe to handle. A quick search verified that the name of the original gifter was a misspelled form of Robert Nininger, who had been involved with the Manhattan Project and (God bless Google) led him to Nininger’s widow who confirmed her husband indeed once had a cube from the reactor but gave it away.
“In that cave laboratory Heisenberg’s team built their last experiment: B-VIII, the eighth experiment of the Berlin-based group … The experimental nuclear reactor comprised 664 uranium cubes, each weighing about five pounds. Aircraft cable was used to string the cubes together in long chains hanging from a lid.”
In his 1953 book Nuclear Physics, German theoretical physicist Werner Heisenbergdetails his work on the Nazi nuclear project conducted in in a cave underneath a castle in Haigerloch, a small town in southwest Germany. He described the cluster of uranium cubes as a “chandelier” and confirmed that this was the most advanced of the various Nazi atomic projects but was not enough to create a nuclear reactor. Working with Miriam Hiebert, a PhD candidate in his department, Koeth found that the cubes were discovered by Allied forces buried in a field, and sent to the U.S. where they ended up in various locations as spoils of war that were never tracked, which explains how Koeth ended up with his.

The recovery of the uranium cubes hidden by German scientists in a field in Haigerloch, Germany during the end of World War II.
“It’s been calculated that the reactor experiment in Haigerloch would have needed about 50% more uranium to run.”
Koeth points out that the design of the Nazi reactor wasn’t the problem — the quantity of uranium was the cause of its failure. Ironically, he and Heibert also discovered that there were 400 more uranium cubes in German in the hands of other projects. Had the German nuclear programs been unified in one location like the Manhattan Project, they would have had sufficient uranium, but possibly not enough heavy water to submerge the chandelier into. Koeth says even less is known about those additional 400 cubes, so he and Heibert have added them to the list as they embark on a new quest to locate those that still exist and determine what happened to the rest of Hitler’s uranium cubes.

A model of the Nazi uranium chandelier (Atomic Heritage Foundation)
“Perhaps most importantly, the story of the cubes is a lesson in scientific failure, albeit a failure worth celebrating. The experiment they were part of, designed by some of the greatest scientific minds of the time, did not work.”
The report ends with the obvious — the Nazi nuclear project didn’t work, even though its scientists were just as sharp as those of the Allies (and sometimes smarter, as the German rocket program proved). What prevented a different outcome was something that students of history remember and leaders of countries forget.
“In science, as in other fundamentally human pursuits, we would do well to remember that we are only truly at our best and most equipped to tackle grand challenges when we put our differences aside and work together.”
Are there enough of Hitler’s cubes left to put one on the desk of every world leader?

https://mysteriousuniverse.org/2019/05/the-search-for-hitlers-cubes-of-uranium/





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