Where would you go in a time machine? Physicist says time travel only goes forward

Summary

Theoretical physicist Hongsheng Zhang shows that travelling backwards in time is mathematically impossible across a broad class of universes. The theorem indicates that moving into the past requires extreme conditions such as spinning black holes or closed spacetime geometry. While forward time travel is physically demonstrated through relativistic time dilation, whether physical nature allows backwards loops remains an open question.

Key Takeaways

1. Hongsheng Zhang, a researcher at the University of Jinan in China, has shown that in a broad class of theoretical universes, travelling into your own past is impossible.
2. Crucially, Zhang's research - which is awaiting peer review - also reveals exactly how a time machine could achieve travelling back in time, and it claims there are only two ways.
3. Einstein showed that moving very fast, or sitting in strong gravity, slows your clock relative to everyone else's.

Statement Breakdown

• Claimed Facts: 85% of statements the article presents as facts
• Opinions: 15% of statements classified as editorial or subjective
• Claims: 0% of statements surfaced for additional reader evaluation

Credibility & Bias Reasoning

Credibility assessment: The report explains theoretical research using standard relativistic concepts and direct quotations from the primary author. It explicitly notes that the underlying paper is currently awaiting peer review. Sourcing relies heavily on an interview conducted by ScienceAlert along with established historical findings in physics.

Bias assessment: Scientific Explainer. The presentation is neutral, educational, and focused on theoretical physics principles. Popular culture references serve merely as introductory hooks rather than ideological commentary. Both the theoretical conclusions and the author's stated caveats are presented in a straightforward manner.

Note: Relies on theoretical physics findings awaiting peer review and historical relativity research.

Credibility flag: Pre-Review Research

Claimed Facts (3)

• States a foundational geometric principle of Einstein's relativity theory.
• Reports a verifiable historical milestone in theoretical physics literature.
• Presents an attributed measurement of relativistic time dilation experienced in orbit.

Opinions (2)

• Reflects the researcher's qualitative characterization of his mathematical proof.
• Expresses personal curiosity and a value judgment about which unanswered question matters most.

Key Sources

• Hongsheng Zhang — Researcher, University of Jinan
• European Space Agency — Intergovernmental space exploration agency
• ScienceAlert — Science news website
• Simon Ormiston — Journalist, Euronews