What would happen if we reach the speed of light?

According to our current understanding of physics, as outlined by Albert Einstein's theory of relativity, reaching the speed of light is not possible for objects with mass. Here are some key points on what would theoretically happen as one approaches the speed of light:

**Mass Increase**: As an object moves faster, its relativistic mass effectively increases. As it nears the speed of light, the energy required to continue accelerating it approaches infinity. Thus, it would require an infinite amount of energy to accelerate a massive object to the speed of light.

**Time Dilation**: Time would appear to slow down for the object moving close to the speed of light relative to an observer at rest. This means that from the perspective of the traveler, less time would pass compared to someone observing from stationary.

**Length Contraction**: In the direction of travel, the object would appear shorter to an outside observer. This phenomenon is known as length contraction and becomes significant as one approaches the speed of light.

**Causality Violations**: If it were hypothetically possible to exceed the speed of light, it might lead to scenarios where causality (the principle that cause precedes effect) could be violated, leading to paradoxes such as time travel.

**Breakdown of Current Physics**: The equations of physics that describe motion break down at the speed of light. For example, the Lorentz transformations, which govern the effects of speed on time and space, do not hold for objects moving at light speed.

**Photon perspective**: For massless particles such as photons (which travel at the speed of light), the concept of time and space is fundamentally different. From the perspective of a photon, the journey from one point to another is instantaneous, as they do not experience time in the conventional sense.

In summary, according to current physics, it is impossible for any object with mass to reach or exceed the speed of light, and doing so would lead to a breakdown of our understanding of space, time, and energy.