If you probe further, you may discover different reasons.

We know from isotopic measurements, stereochemistry, and gas chromatography/mass spectrometry, that the production of hydrocarbons in the Earth occurs on timescales ranging from fractions of a megayear to hundreds of megayears, in a temperature regime in the rough range of 0-200°C, and in an evolving environmental smog of sedimentary pores containing water laced with varying amounts of ions, molecules, and minerals.

The decade produced a whole crop of ideas about space travel.

The putative force of hostageship as a form of surety lay in the threat to the life of the hostage in case of default; ties of blood magnified the threat, hence the prevalence of sons as hostages.