Chosen answer:As of season three it has not been explained. The characters gained powers after the solar eclipse of the first episode and temporarily lost them during "The Eclipse". It could be some form of cosmological radiation, Hiro and Ando make Superman analogies (who only has special powers because of Earth's yellow sun), Suresh believes it may be coincidental, or it might possibly be related to the catalyst, or it could be influenced by an as yet unseen character.
Chosen answer: As of season three it has not been explained. The characters gained powers after the solar eclipse of the first episode and temporarily lost them during "The Eclipse". It could be some form of cosmological radiation, Hiro and Ando make Superman analogies (who only has special powers because of Earth's yellow sun), Suresh believes it may be coincidental, or it might possibly be related to the catalyst, or it could be influenced by an as yet unseen character.
Sanguis