According to our current understanding of physics, there is no known method for traveling back in time, even without surpassing the speed of light. The concept of traveling backward in time while remaining within the bounds of the known laws of physics is still purely speculative and lacks scientific evidence.
The theory of relativity, proposed by Albert Einstein, describes the relationship between space and time, and it suggests that time travel into the past would involve scenarios that violate the principles of causality. These violations can lead to paradoxes, such as the famous grandfather paradox, where an individual could potentially prevent their own existence by traveling back in time and altering events.
However, it is important to note that our understanding of the universe is always evolving, and there may be future discoveries or developments in physics that could challenge or expand our current understanding of time and its potential manipulation. Nonetheless, at present, time travel into the past remains purely speculative and falls outside the realm of established scientific principles.