Comment by mikkupikku

Have you read the paper itself, not just summaries of the idea? It's obvious from the way he wrote it, dripping in sarcasm. Talking about "Malthusian principles" and "Lebensraum", while hand waving away any common sense questions about how the mass of Jupiter would even be smeared into a sphere around the sun, just saying that he can conceive of it and therefore we should spend public money looking for it. He's having a lark.

Also, he literally said it was a joke, and was miffed that he was best know for something he didn't take seriously.