[frankquist]

Say these were aliens with an antigravity drive. They may be scientists who do not want to disturb the phenomena they are observing. They might have a Starfleet like noninterventionist philosophy. Perhaps the objects are unmanned probes akin to the ones earth sends into space.

Who knows?

[valuearb]

They could be Mohammed, or Jesus. Who knows?

[tripzilch]

Yeah but in all fairness, even among humans, so many people go by those names. If Ford Prefect had paid a bit more attention when he first arrived, he might have gone with one of those as well, instead.