According to our current understanding of physics, time travel into the past is not considered possible within the realms of classical physics. The concept of time travel raises many paradoxes and logical inconsistencies, such as the famous grandfather paradox, where going back in time and changing events could potentially lead to contradictions.
In classical physics, time is considered a one-way arrow, and events occur in a chronological order. However, it's important to note that some theories in modern physics, such as general relativity and quantum mechanics, allow for theoretical possibilities of time travel under certain conditions, although these concepts are still highly speculative and not yet confirmed by experimental evidence.
For example, in general relativity, there are solutions called "wormholes" that connect distant regions of spacetime. These wormholes could potentially allow for a shortcut through spacetime, but they come with immense challenges, such as the need for exotic matter with negative energy density to stabilize them. The existence and practicality of wormholes are still purely theoretical and require further scientific exploration.
As for the idea of going back in time to change one's own history for personal gain, it remains purely speculative and hypothetical. It is difficult to predict the consequences and potential paradoxes that could arise from altering the past. Many scientists and philosophers argue that the laws of physics may prevent any changes to the past, ensuring a consistent and causally ordered universe.
It's important to remember that scientific theories and our understanding of the universe are constantly evolving. While time travel into the past remains a topic of scientific speculation, at present, it is not considered a feasible or proven concept.