Infinite mass at speed of light?

[Antuanne]

The relativistic mass formula is m=γm, and at the speed of light, relativistic mass is infinity. But, the Lorentz factor at the speed of light is 1/0, but this is undefined, so why do physicists call this "infinity"?

 

[Nugatory]

The relativistic mass formula is m=γm, and at the speed of light, relativistic mass is infinity. But, the Lorentz factor at the speed of light is 1/0, but this is undefined, so why do physicists call this "infinity"?

They don't, and you've been victimized by the pop-sci crowd looking for easy non-rigorous gee-whiz "explanations".

Around here, you're more likely to get responses saying that questions about the mass of an object traveling at the speed of light are meaningless, for roughly the same reason that questions about what would happen if pigs could fly are also meaningless.

 

[leo nardo]

So no mass can reach the speed of light and your Lorenz factor will never produce an infinitive number.
An example: when an observer A brings some mass M at 99% of c it's mass seems to be 7 times larger. (factor 0.7*√(c/c-v).
For another oserver B traveling along with M the mass does not change in his reference frame. So he pushes mass M again at 99 % of c.
Now to B mass M again seems 7 times larger, but to A it seems 70 times larger. (Also here mass is calculated as force/acceleration)
You can try to repeat this an infinite number of times. And every time the mass M seems to grow with a factor of 10 to the original observer. But you will never reach c.
Hope this is helpful.

 

[Chronos]

Use of the term relativistic mass has fallen from favor among professionals. It was orginally used as a way to explain why a massive object could not be accelerated to the speed of light, but, had more confounding than explanatory power. It invited wildly erroneous conclusions - like an electron would become a black hole if sufficiently accelerated.

 

[sardar]

First of all, it is important to clarify that the concept of "infinite mass" at the speed of light is a theoretical concept in the context of Einstein's theory of relativity. In reality, it is impossible for any object to reach the speed of light due to the fundamental laws of physics.

Now, to address the question, the term "infinite mass" is used in a mathematical sense to represent the limit of the relativistic mass formula as the speed approaches the speed of light. This means that as an object approaches the speed of light, its relativistic mass increases towards infinity. However, this does not mean that the object actually has infinite mass. It is a mathematical concept used to describe the behavior of objects at extremely high speeds.

As for the Lorentz factor at the speed of light being undefined, this is because the Lorentz factor is derived from the speed of the object relative to the speed of light. Since the speed of light is the maximum speed in the universe, it cannot be used in the calculation, resulting in an undefined value. This does not invalidate the concept of infinite mass, as it is a separate concept derived from the relativistic mass formula.

In conclusion, the term "infinite mass" at the speed of light is a theoretical concept used to describe the behavior of objects at extremely high speeds in the context of relativity. It is not a physical reality, but rather a mathematical representation of the behavior of objects in the universe.