August 1981, a British ship disappeared with 6 people reappeared after 8 years.  In 1954, a gas flying balloon disappeared during a competition from Caribbean. In 1990 the ballon reappeared and the riders only thought is a while but it is after 36 years.

Could it be possible because some factors they have been transformed into other dimensions and transport back sometimes later.  The knowledge can be immense but it does create more angles for thinking possibilities.