OOC :
E=mc squared. Energy can be directly converted into mass, although it does take rather a lot of it. However, given the huge supply of energy available to things in open space without atmospheric shielding, and a length of time comparable to even our own relatively young planet of Earth, it is possible for enough energy to be converted into mass to form a planet-sized object. As gravity increases more atmosphere will be retained (assuming some sort of magnetic field, which is possible, just not very likely without minerals), and the thickness of the atmosphere, and probably an Ozone layer, which will block much of that radiation. By this time, though, the mass and dimension of the object will be sufficient to promote collisions with space-junk (meteors) which will also, very slowly, add to the mass of the body. Although, as metors tend to be Nickle and Iron rich, we return to minerals being present...somewhere.
Atys may well have grown without any starting mass to grow from, a microscopic spore floating through space.
IC:
Aye, dis ball grewed aight. Jus waits till Ma-Duk finds dem secret numbers an' names, mebbee den he stop holtin out on de knowledge. Dratted gods
Baxter- Digger, crafter, explorer, and dirty little man.
"Thar ain nuthin nor nobudy wot be so good as dey canna be betterer."
More power for Homins!
P~)
Ouroborus Nocturna
I'm not so sure about Episode 2. 
