Physicists Explore a Possible Breakthrough for Time Travel

Scientists are uncertain whether cosmic strings exist, but if they do, these mysterious structures could revolutionize our understanding of the universe—and even make time travel possible.

If physicists can confirm the existence of cosmic strings, they may pave the way to achieving the “Holy Grail” of physics: a unified theory that combines quantum mechanics with Einstein’s general theory of relativity. Beyond this, cosmic strings could hold the key to bending spacetime and enabling time travel.

Theoretical models suggest cosmic strings are extraordinarily thin, far smaller than the nucleus of an atom, yet immensely massive—equivalent to tens of thousands of stars.

These long, thread-like structures are believed to either stretch infinitely across the universe or form closed loops. As they oscillate and gradually shrink, they emit gravitational waves. A typical loop of a cosmic string might span 10 to 20 light-years.

Physicists theorize the existence of two types of cosmic strings.

Cosmic Superstrings: Rooted in string theory, these strings are thought to be stretched throughout the cosmos.

String theory posits that the fundamental particles of the universe are tiny, vibrating strings, and it strives to develop a “theory of everything.” Superstrings could offer insights into the fabric of reality and might even provide a mechanism for time travel.

Relics of the Early Universe: These cosmic strings are hypothesized to have formed during the universe’s earliest moments, as it cooled after the Big Bang.

During this period, the four fundamental forces—gravity, electromagnetism, and the strong and weak nuclear forces—began to separate. This process may have created “cracks” in spacetime, leaving behind these structures, often referred to as the “hidden scars” of the universe.

Astrophysicist J. Richard Gott of Princeton University suggests that cosmic strings could unlock the secret of time travel. According to his theory, two cosmic strings moving near the speed of light could distort spacetime in such a way that they form a loop—a wormhole through which time travel might be possible.

Einstein’s general theory of relativity allows for the possibility of spacetime curving back on itself, creating time loops. Gott theorizes that the immense gravitational pull of cosmic strings could bend spacetime into shortcuts, or wormholes.

For instance, if a spaceship traveled between two planets and encountered a cosmic string, it could traverse the distance far faster than light traveling in a straight line. This might allow the travelers to arrive at their destination before observing themselves leaving.

Furthermore, two cosmic strings moving in opposite directions and intersecting could create a time loop. By traveling along this loop, one could theoretically journey into the past.

Detecting cosmic strings, however, is extraordinarily challenging. Their extreme density should warp spacetime, causing a gravitational lensing effect that would make distant galaxies appear duplicated. Yet, if cosmic strings are lighter than expected, this lensing might not occur.

Gott proposes another detection method: observing gravitational microlensing events. These occur when a passing cosmic string briefly magnifies the brightness of a star.

Such observations could confirm the existence of cosmic strings and potentially lead to a Grand Unified Theory—a framework that unifies all known physics into a single, coherent model.