According to the theory of relativity, as formulated by Albert Einstein, no object with mass can reach or exceed the speed of light in a vacuum, which is approximately 299,792,458 meters per second. This principle is known as the "universal speed limit."
When we talk about the speed of an electron in the context of its rotation or spin, it's important to note that the term "spin" is somewhat misleading. In quantum mechanics, electron spin is an intrinsic property that does not involve actual physical rotation in the way we typically understand it.
The spin of an electron is described by its spin quantum number, which takes on values of either +1/2 or -1/2. It is not related to literal spinning motion but rather represents a fundamental property of the electron's angular momentum. The spin of an electron is not constrained by the speed of light because it is an inherent quantum property, not a macroscopic velocity.
Therefore, the concept of an electron's spin is not limited by the universal speed limit imposed by the theory of relativity. The speed at which an electron "spins" is not a speed in the conventional sense but rather a measure of its quantum mechanical properties.