According to our current understanding of physics, it is not possible for an object with mass to travel faster than the speed of light in a vacuum. The speed of light, denoted by 'c,' is considered an absolute speed limit in the theory of relativity. As an object with mass approaches the speed of light, its energy and momentum increase, making it increasingly difficult to accelerate further. It would require an infinite amount of energy to accelerate a massive object to the speed of light, let alone surpass it.
When an object with mass approaches the speed of light, its relativistic mass increases, time dilation occurs, and its length in the direction of motion contracts. These effects are described by the theory of special relativity. As the object's velocity approaches 'c,' its mass becomes infinite, and time dilation and length contraction become more pronounced, making it impossible to reach or exceed the speed of light.
As for measuring the speed of an object, we typically use various instruments and techniques to determine its velocity relative to a reference frame. In everyday situations, we commonly use devices like speedometers or radar guns to measure speeds. In scientific experiments, more sophisticated methods such as laser interferometry or Doppler shift measurements may be employed to determine velocities accurately.
It is worth noting that there is a concept called the "speed of light in a medium" or "phase velocity," which can be slower than the speed of light in a vacuum. This occurs when light travels through a material medium, such as glass or water, where it interacts with the atoms and molecules of the medium, causing a delay. However, even in these cases, the speed of light within the medium still obeys the fundamental rule that it cannot exceed 'c' in a vacuum.
In summary, according to our current understanding of physics, traveling faster than the speed of light is not possible for objects with mass. The theory of relativity provides a comprehensive framework explaining the behavior of objects approaching the speed of light and establishes 'c' as an absolute speed limit in the universe.