According to our current understanding of physics, it is not possible for an object with mass to travel at or exceed the speed of light in a vacuum. The theory of relativity, proposed by Albert Einstein, tells us that as an object with mass approaches the speed of light, its relativistic mass increases, and the energy required to accelerate it further also increases. This means that an infinite amount of energy would be needed to accelerate an object with mass to the speed of light, making it impossible to reach or surpass that speed.
However, let's assume for the sake of speculation that you somehow manage to travel at or above the speed of light. In that case, several consequences would emerge based on the predictions of special relativity:
Time dilation: According to the theory of relativity, time would slow down for you relative to a stationary observer. As you approach the speed of light, time dilation becomes more pronounced. From your perspective, time would appear to pass normally, but for an outside observer, time would appear to slow down or even come to a standstill.
Length contraction: As you accelerate towards the speed of light, the length of objects in the direction of your motion would appear to shrink from your perspective. This phenomenon is known as length contraction.
Mass increase: As mentioned earlier, the relativistic mass of an object increases as its speed approaches the speed of light. The faster you move, the more mass you would appear to have. At the speed of light, your mass would theoretically become infinite, which is not possible according to our current understanding of physics.
Energy requirements: As you approach the speed of light, the amount of energy required to accelerate further also increases significantly. In fact, the energy required to accelerate an object with mass to the speed of light would be infinite. This concept is often expressed through Einstein's famous equation E=mc², where E represents energy, m represents mass, and c is the speed of light.
These are some of the predicted effects based on the theory of relativity. However, it's important to note that traveling at or above the speed of light is currently considered impossible for objects with mass, according to our current understanding of physics.