Complex sentence: Currently, none of the period 8 elements have been discovered yet, and it is also possible, due to drip instabilities, that only the lower period 8 elements, up to around element 128, are physically possible.
Split into simpler sentences: Currently, none of the period 8 elements have been discovered yet. It is also possible, due to drip instabilities, that only the lower period 8 elements, up to around element 128, are physically possible.