Convert from petagram to obol, obolos, obolus [Greece]

Unit Definition (petagram)
The petagram is a metric unit of mass equal to 10E15 grams or 1 gigatonne (one billion metric tons). This unit is used in atmospheric science and other scientific contexts where large masses are considered.

Unit Definition (obol, obolos, obolus [Greece])
The obol, obolos, obolus [Greece] is a historic unit of weight or mass. The obol is a very small weight that originated as the weight of a tiny Greek coin. In modern Greece, the obolos is an informal name for the decigram (0.1 gram).