We can travel at the speed of light to every location in the universe in the shortest period, the length of time we travel. So, time travel is the concept of going between a few locations at a time, analogous to an item or person moving between various points in space using an imagined contraption known as a time machine.
The Origins of Time Travel
Before 1895, only scientists were interested in time travel; nevertheless, it is today a popular concept in philosophy and literature. However, H.G. Wells' book The Time Machine was the first to bring the concept of a time machine to the public's notice in 1895.
Time travel is referenced in the Mahabharata.
The Mahabharata narrates the account of King Kakudami, who travels to Heaven to see Brahma, the God who created the universe. Returning to Planet, he is astounded by how many epochs have gone.
Buddhism and time travel
The Buddhist Pali canon discusses the concept of time being relative. Payasi Sutta narrates the account of Kumara Kaspa, one of the Buddha's most significant disciples, who convinces Payasi and other skeptics that time flows differently in Heaven than on Earth.
Time travel narrative in Japanese
In the Japanese novel Urashima Taro, a young fisherman called Urashima Taro visits a sea castle. When he arrives at his village home a few days later, he discovers that he has been forgotten, that his house is in ruins, and that his family has perished.
A Jew travels through time.
According to Jewish legend, the scholar Honi ha-Magel, who flourished in the first century BC, slept for seventy years. He doesn't see anybody he knows when he gets up and goes home. No one believes what he says about himself when he claims to have been sleeping for 70 years.
Physicists believe in time travel.
According to the special theory of relativity, proposed in 1905, individuals traveling a distance from each other see time passing at different speeds. However, the impact does not alter while traveling at the speed of light.
With the correct geometries of spacetime or certain types of motion in space, special and general relativity predict that it may be feasible to travel across time into the future. Many experts believe that humanity will never be able to go back in time.
It also claims that any hypothesis that allows you to return in time would generate complications. Some physicists, including Novikov and Deutsch, have claimed that these temporal conflicts may be avoided by employing the Novikov self-consistency theory or an alternative way of seeing the many-worlds interpretation.
The theory of general relativity
According to general relativity, if a human travels at the speed of light in a spaceship and subsequently returns to Earth, just a few years pass aboard the spacecraft while many years must pass on Earth. It's known as the "twins paradox." Because a traveler will be significantly younger than his twin when he returns from such a journey.
It is possible to go back in time at the speed of light in general relativity and certain spacetime geometries, such as cosmic strings, transverse wormholes, and the Alcubierre drive. In certain unique cases, the theory of general relativity gives a theoretical foundation for traveling back in time. However, semiclassical gravity arguments show that these weaknesses may be solved when quantum effects are included in general relativity.
Stephen Hawking used these semi-quantitative arguments to create his chronological conservation hypotheses. He claimed that the fundamental rules of physics forbid time travel. Physicists have yet to combine general relativity with quantum mechanics, including quantum gravity. Without a fully integrated theory, there is no way to reach a definitive judgment concerning relativity.
Different geometries of spacetime
General relativity is a theory that describes how the cosmos operates. It relies on field equations demonstrating how distance works in the spacetime metric. These equations have precise solutions, such as complete time-like curves or world lines trailing each other. Since of how the world works, some beat in the future is also some point in the past.
Kurt Godel was the first to propose this approach- the Godel metric. However, his, as well as other people's, answers rely on physical aspects of the cosmos that appear to be to be true. Two examples are that it does not move or the Hubble expansion. Whether general relativity slows down as closed time in all conditions is still being researched.
Wormholes
Wormholes are a compound technique for Einstein's general relativity field equations to bend spacetime. Some scientists believe a travelable wormhole may be exploited to transit back in time. This would imply exceeding the speed of light, which is impossible.
However, relativity may be discovered in general. This is Einstein's theory of gravity, which integrates space and time into "spacetime" and states that the quantity of spacetime decreases when there is mass.
This enables the creation of wormholes, tunnels across spacetime that link portions of the universe that are otherwise extremely far apart. If the wormhole's mouth moves relative to each other, a passenger traversing the bridge between two places in space will also end up at a different moment from where they began.
However, traveling back and forth from wherever the wormhole would have formed would be impossible. This would make travel more difficult, which is likely why we haven't encountered anybody from his future yet. If the Big Bang generated a natural wormhole, traveling back in time and to distant parts of the universe might be feasible.
Quantum physics
Even more limiting, Kip Thorne's theoretical theory, which partly mixes general relativity and quantum mechanics, predicts that any wormhole that allows you to travel across time collapses as soon as it is created. In other words, the wormhole is short-lived.
Grandfather paradox
However, Thorne eliminated an evident difficulty that may have arisen due to time travel. The grandfather paradox occurs when a person travels back in time and murders their grandpa before envisioning their father. This prevents the individual from being born, making killing the grandpa by traveling back in time impossible. Thorne discovered that when a point mass passes via a wormhole, this contradiction does not occur.
Conclusion
Returning to the past or forwards in time to the future is called time travel. Although time travel is unlikely in the present world, it is employed in fiction.