According to our current understanding of physics, backward time travel, also known as traveling into the past, is not considered possible. The concept of time travel to the past raises numerous paradoxes and conflicts with the fundamental laws of physics as we currently know them.
One of the main reasons backward time travel is considered implausible is the violation of causality. Causality is the principle that an event must occur before its effects. If time travel to the past were possible, it could lead to situations where events cause their own causes, creating paradoxes such as the famous "grandfather paradox" where a person travels back in time and prevents their own grandparents from meeting, thereby negating their own existence.
While some theories in physics, such as general relativity and certain solutions to Einstein's equations, allow for the theoretical possibility of closed timelike curves (CTCs) that could in principle enable time travel, they require exotic forms of matter or energy that have not been observed or successfully created. Additionally, these theoretical possibilities often result in logical inconsistencies or violations of known physical principles.
It's important to note that the topic of time travel is still a subject of active scientific inquiry and speculation. Some physicists explore the concept in theoretical frameworks like quantum mechanics, string theory, or the study of wormholes. However, there is no consensus among physicists regarding the feasibility of backward time travel, and it remains largely in the realm of science fiction.
Until new scientific discoveries or breakthroughs provide a more comprehensive understanding of the laws of physics and their implications for time travel, the prevailing view is that backward time travel is highly unlikely, if not impossible.