P'Chek's atmosphere was almost as dense as that of Goroth Prime and consisted almost purely (98%) of oxygen, with the only other major component being helium. Planetologists however were unable to find a scientific explanation for the origin of such an atmosphere in absence of any plant life on the moon.
P'Chek had once been inhabited by an unknown species which presumably died out a long time before the Galactic Civil War. Ruins of articifial structures were found around the "coastlines" of large shallow depressions that might once have been ocean beds. Carbon-dating and other techniques indicated an astounding age of more than one billion years.
Astonishingly the architectural features of these ruins seemed to be quite similar to structures build today by the Twi'lek species from the Outer Rim world of Ryloth. There are however no existing records of Twi'leks ever visiting the Goroth system, and considering that their culture was fairly primitive when Ryloth was discovered by Old Republic explorers approximately 10,000 years before the onset of the Clone Wars, P'Cheks native name—"Mystery"—remains more than fitting.