U-Be Spherules? Think Nuclear Weapons
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It’s always dangerous scientifically to decide on a conclusion and then look for supporting data. Tempting, certainly, and it’s not a bad way to start off an investigation. But you can’t get too attached to that conclusion. Chances are that you’ll find that someone else disproved it or that the data just don’t support it.
Avi Loeb, a theoretical physicist at Harvard, believes that ‘Oumuamua, an object that quickly transited the solar system from somewhere else in 2017, was an alien spacecraft. It’s generally agreed that ‘Oumuamua came from outside the solar system. Alien spacecraft, not so much.
But let’s look for data! Aha, in 2014, a meteor that had an orbit that could have come from outside the solar system fell in the ocean near Papua New Guinea! If fragments could be found, they might be analyzed.
So Loeb got funded by a cryptocurrency magnate and used a magnet to trawl the seafloor in the area to pick up fragments. He got some interesting spherules. Spherules are formed by melted meteors, volcanoes, and nuclear explosions. These spherules are enriched in beryllium, lanthanum, and uranium. Apparently the group measured no isotope ratios, which could be persuasive for an Earth or non-Earth origin. Loeb, of course, leans toward non-Earth, non-Solar-System.
Cosmochemists are critical of the quality of the data and would like to see isotope ratios.
I have some thoughts on the origin of the spherules.
Another theoretical physicist we’ve been hearing about would likely think first of a different origin of the particles when he learned that they had excesses of beryllium, lanthanum. and uranium. Beryllium and uranium are components of nuclear weapons. Lanthanum, maybe sometimes. It certainly is a fission product, but I would have to do more digging to see if fission products decay to stable lanthanum isotopes.
The Marshall Islands, where the United States did 24 atmospheric nuclear tests, some of them very large, are about a thousand miles northeast of Papua New Guinea. The Castle Bravo test famously exceeded expectations with a 15 megaton yield. Prevailing winds would drive fallout from US nuclear tests toward Papua New Guinea.
A nuclear explosion melts material in its immediate vicinity and incorporates its own components into the melt. The melt rains down, some of it in spherules, just as spherules from a meteor would. That is how Trinitite, the glassy material that covered the ground after the first nuclear test, formed. Photos of small Trinitite particles, some of them spherules, can be seen in this publication, which details the formation process. I have a tiny black spherule, a couple of millimeters in diameter, that I picked up at the site of the first Soviet nuclear test.
More details about Loeb’s spherules could clear up their origin. Historical data on winds at the time of nuclear tests or isotopic data on the uranium would be helpful.
I attached a tweet suggesting a nuclear test origin to one of the group’s tweets about their results. I haven’t heard back.
A couple of other people tweeted that “the Medium page” (no link given) says that the elemental abundances don’t match nuclear weapons fallout. I would like to see the comparison data they used. Trinitite is not of a uniform composition. Most of it is green, but if parts of the tower or weapon were incorporated, it can be red or black.
Cross-posted to Nuclear Diner