This is the worst sort of clickbait article, relying on people's ignorance and credulity. Loeb is a well-known crank (Harvard seems to specialize in churning them out) and no one listens to his rantings any more. There is no "alien artifact" under the ocean. Merely because something may have an origin outside the solar system does not make it a fabricated object fashioned by some magical alien intelligence. Looking for a lump of space debris would, however factual, make for a less trashy article so the author opted for trash because, as we know from politics, lies and other babble is more attractive to simple minds than hard-nosed reality.