Loeb's interstellar spherules have caused controversy and indignation amongst experts in the science community.
For those of you not-in-the-know, Loeb travelled to the site of a proposed interstellar meteor (his designation: IM1) which he had identified in a catalogue of bolides held by NASA and then discovered in the ocean tiny metallic blobs he purports to be of extrasolar composition. He even suggests that IM1 could have been tech made by an alien civilization.
Scientists around the world have raised myriad concerns over the claim. Let me elucidate on some.
Firstly, Loeb dredged the specific region of the ocean he was interested in and did NOT sufficiently investigate a wider area of the ocean. This would have then enabled a better determination of whether these spherules originated from IM1 or were just generally distributed background noise (so not associated with IM1).
Secondly with an iron-rich object travelling through the atmosphere at a speed of 45 km/s the intensity of the explosions would have produced only a small quanitity of spherules (if any at all).
Thirdly if the spherules did impact on the ocean surface, they would sink very slowly and by assuming 'Stokes Flow' over a depth of 2-3km, they would have been carried away to distant locations by currents and so there would be unlikely any under the path of the meteor.
There are other concerns which I shan't articulate here but you get the general idea.
He seems to want to be proved RIGHT about his proposal that 'Oumuamua is alien technology, and will go to extraordinary lengths to do so apart from possibly the most obvious way of doing this - actually MOUNTING A MISSION (in other words PROJECT LYRA).