Physics trivia

# Is time travel possible?

The theories of physics do not preclude the possibility of time travel, but to say that an event is possible does not mean that it is executable.

The possibility of traveling through time and reliving the past or knowing the future has always intrigued people and been the subject of many movies and comic books. Some films have marked history by presenting the possibility of time travel . Examples are the features Back to the Future (1985), The Time Machine (2002), Straitjacket (2005), Lake House (2006), Man from the Future (2011) and Interstellar (2014).

Theories of Physics do not exclude the possibility of time travel, but there is a big difference between the natural possibility and being able to execute an event. Being possible does not mean being executable. space-time

continuum

Physics analyzes time as a fourth dimension. Thus, we observe and interact with height, width, depth and time. The temporal and spatial dimensions are directly connected. Space and time are intertwined and encompass the entire universe, forming the so-called space-time continuum .

time is not absolute

The idea is adopted that time is something absolute, which always progresses in the same way for all points in the universe. The theory of relativity , proposed by Einstein in 1905, shows the relativity of time for observers under different conditions. Just as an object is perceived differently by observers in different positions, time can be analyzed from different perspectives . A minute marked on Earth is not equivalent to a minute everywhere in the universe.

Theoretically, there are a few ways to alter the space-time continuum and make time be perceived differently by different observers.

I. Accelerate to speeds close to that of light

When accelerating a body at speeds close to the speed of light (3.0 x 10 8 m/s) , time will pass more slowly. Time dilation proposes that an observer moving with speed close to the speed of light will always mark shorter time intervals than an observer at rest.

II. Position yourself in the vicinity of a black hole

Gravity modifies space-time.

The greater the gravity, the less the perception of time will be due to the distortions generated in space-time.

III. Use a wormhole

Wormholes are a kind of funnel between two very distant points in space-time. Upon entering one of these holes, the traveler would be taken to a place in very distant space and time. Wormholes are theoretical possibilities. There is no deep experimental proof of its existence.

travel in time

Time travel would not occur like in the movies, where a portal is opened and, as if by magic, one travels through space-time. What would actually happen would be different time perception for two different observers.

Imagine an astronaut who wandered through space in a spaceship at the speed of light for a year. Upon returning to Earth, a stationary reference, seventy years of his departure would have passed. Thus, we can consider the astronaut as a time traveler.

If time travel were really possible, there must be laws of nature that prevent a traveler from altering his history or that ensure that changes made by the traveler always result in the world he left behind.

Faced with all the implications, we can understand that time travel is extremely unlikely.