According to our current understanding of physics, as described by Einstein's theory of relativity, it is not possible for any object with mass to move faster than the speed of light in a vacuum. This is because as an object with mass approaches the speed of light, its energy and momentum increase towards infinity, which would require an infinite amount of energy to achieve, violating the known laws of physics.
As for time travel, the theory of relativity also provides insights. According to it, time is not an absolute quantity but is relative to an observer's frame of reference. Time dilation is a phenomenon predicted by relativity, where time can appear to pass differently for objects in relative motion. When an object moves at speeds close to the speed of light, time slows down for that object relative to a stationary observer.
However, even though time dilation occurs, it does not allow for direct control or manipulation of time to travel freely into the past or future. The time dilation effect observed at high speeds is asymmetric and limited. While an object moving at high speeds experiences time dilation relative to a stationary observer, it remains within its own frame of reference. It cannot, for example, travel back in time or skip forward to a specific future moment.
The concept of time travel, particularly backward time travel, involves numerous complex challenges and paradoxes. The causal loops, grandfather paradox, and other logical inconsistencies arise when considering the ability to change events in the past, leading to inconsistencies and contradictions. These paradoxes suggest that the laws of physics, as we currently understand them, do not allow for conventional time travel.
It's important to note that our understanding of the universe is continually evolving, and new discoveries and theories may provide fresh insights into the possibilities of time travel. However, as of now, our scientific understanding suggests that faster-than-light travel and conventional time travel are not feasible within the framework of known physical laws.