What if Earth has a large deposit of element 115 somewhere? Perhaps when Theia hit earth 4.5 billion years ago, it deposited element 115 in two great blobs in the earths mantle. (hivelink)
Perhaps at least 100 million years ago, another technological civilization evolved on earth and found 1 decent deposit of pure element 115 very early in their history.
(hivelink)- Then perhaps this civilization learned to use element 115 for antigravity travel and even interstellar travel. It then expanded out without leaving much trace or evidence. tid:3430 (1) (hivelink)
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