Does the crossing in the novel really exist?

Time travel exists. There were factual records in news records and mystery novels at home and abroad a few years ago. For example, before World War II, people who disappeared in a foreign hot air balloon competition and reports in hot air balloon competitions decades later can prove the existence of time travel. However, modern technology has not been mastered. Just visiting may be a wormhole, which is in a "quantum bubble", and so on.