According to the theory of special relativity, which was proposed by Albert Einstein, the mass of an object increases as its velocity approaches the speed of light. However, it is important to note that the concept of mass becoming infinite at the speed of light is a common misconception.
In special relativity, mass is not considered a fundamental quantity but rather a measure of an object's energy content. The equation that relates an object's energy (E), mass (m), and the speed of light (c) is given by E = mc^2, where c is the speed of light in a vacuum (approximately 3 x 10^8 meters per second).
As an object with mass accelerates to higher velocities, its energy increases. This increase in energy is often referred to as "relativistic mass" or "apparent mass." The relativistic mass (m') of an object moving at a velocity (v) can be calculated using the equation m' = m / sqrt(1 - (v^2 / c^2)), where m is the object's rest mass (mass at rest).
As the velocity of an object approaches the speed of light, the term (v^2 / c^2) in the denominator of the equation approaches 1, making the denominator very close to zero. When the denominator becomes zero, the equation becomes undefined, suggesting that it is not possible for an object with mass to reach or exceed the speed of light.
In the theory of special relativity, it is postulated that objects with mass can never reach or exceed the speed of light. As an object approaches the speed of light, its relativistic mass continues to increase, but it never becomes infinite. Instead, the energy required to accelerate the object further also increases, making it progressively more difficult to achieve higher velocities.
It is worth noting that the concept of relativistic mass is not commonly used in modern physics. Instead, the concept of mass as the intrinsic property of an object remains unchanged, and the energy and momentum of an object are described using different equations that take into account relativistic effects.