The main question here is not whether Oumuamua was a hydrogen iceberg, but rather whether hydrogen icebergs are possible. Solid hydrogen is terribly difficult

The main question here is not whether Oumuamua was a hydrogen iceberg, but rather whether hydrogen icebergs are possible. Solid hydrogen is terribly difficult to study [1]. Solid hydrogen does not exist at pressures below 100 GPa (i.e. 1 million times higher than the atmospheric pressure). These pressures occur deep inside Jupiter, for example, but how do you get the "hydrogen iceberg" free? [1] https://en.wikipedia.org/wiki/Solid_hydrogen https://en.wikipedia.org/wiki/Solid_hydrogen