According to our current understanding of physics, objects with mass cannot travel faster than the speed of light in a vacuum. This is a fundamental principle known as the "speed limit" of the universe. As an object with mass accelerates towards the speed of light, its energy increases, and its mass appears to become infinite. This would require an infinite amount of energy, which is not feasible based on our current understanding of physics.
Now, if we were to hypothetically imagine an object that could exceed the speed of light, it would have significant implications for our understanding of spacetime. According to the theory of special relativity, which describes the behavior of objects moving at speeds close to the speed of light, as an object accelerates towards the speed of light, time dilation occurs, meaning time slows down relative to a stationary observer. This effect becomes more pronounced as the object approaches the speed of light. If an object were to surpass the speed of light, it would imply that time would need to reverse or behave in a manner that contradicts our current understanding.
Regarding your question about accessing the fourth dimension, it's important to note that the concept of dimensions can be interpreted in different ways. In the context of spacetime, time is considered the fourth dimension, and the three spatial dimensions (length, width, and height) make up the other dimensions. However, in other mathematical or theoretical frameworks, the concept of additional dimensions beyond the familiar three spatial dimensions and one temporal dimension can be postulated, such as in string theory.
If we were to speculate about an object traveling faster than light and somehow accessing additional dimensions, it would be purely speculative and hypothetical, as it goes beyond our current understanding of physics. It's worth noting that the existence and properties of additional dimensions are areas of active research, and various theories, such as string theory or brane cosmology, propose the existence of extra dimensions, but these are currently theoretical and have not been experimentally confirmed.