Time Travel Physics: Understand the Real Possibilities of Temporal Movement

Greer John is a science writer and educator specializing in theoretical physics and cosmology. With a background in both physics and science communication, John has spent over two decades translating complex scientific concepts into accessible and engaging prose for general audiences. A former contributing editor at *Physics Today*, John's work has appeared in *Scientific American*, *New Scientist*, and *Wired*, covering topics ranging from quantum mechanics and relativity to the origins of the universe and the frontiers of space exploration.

John is the author of four previous books on popular science, including *The Quantum World: A Beginner's Guide to the Strange Physics of the Very Small* and *Dark Matter and Dark Energy: The Invisible Universe*, both of which were praised for their clarity and depth. John's writing has been recognized by the American Institute of Physics with the Science Communication Award, and by the National Association of Science Writers with the Excellence in Science Journalism prize.

In addition to writing, John has developed and taught online courses in modern physics for platforms including Coursera and edX, reaching hundreds of thousands of students worldwide. John's teaching approach emphasizes intuition and conceptual understanding over mathematical formalism, making advanced topics accessible to learners without a physics background.

Before turning to full-time science writing, John conducted research in theoretical cosmology at the Institute for Advanced Study in Princeton, where the focus was on the early universe, cosmic inflation, and the arrow of time. This research background provides a solid foundation for the explorations in this book.

John lives in Portland, Oregon, where time is spent reading, hiking, and working on the next book—a deep dive into the physics of black holes and their role in the universe.