And this is what they call science nowadays? Let’s just make up a theory knowing that it can’t be proven?
I don’t know. You’ve got some isotopes that don’t exist normally on earth. They are however a product of supernovas. They didn’t come from here. It’s not a big leap to the reasoning of this study. Proven? Yes to a good degree of certainty. It is however, like all hypothesis, subject to challenges and is not “settled science” but has a reasonable degree of probability. I don’t know much in science that isn’t open to challenges.