No, you cannot measure time with a ruler according to special relativity. Special relativity, developed by Albert Einstein, describes how the laws of physics appear to observers moving relative to each other at constant velocities. It introduces the concept of time dilation, which means that time can appear to pass differently for observers in relative motion.
According to special relativity, the passage of time is not an absolute quantity, but depends on the relative velocities of observers. As an object's velocity approaches the speed of light, time dilation becomes significant. Time slows down for a moving object relative to a stationary observer. This effect has been experimentally verified numerous times and is a fundamental aspect of the theory.
A ruler is a physical object used for measuring distances, and it cannot directly measure time. Time measurements require different methods, such as clocks or other timekeeping devices. These devices are designed to account for the effects of time dilation and provide accurate measurements of time, regardless of the relative motion between observers.
In summary, special relativity does not allow you to measure time with a ruler directly. Time and space are intertwined, and their measurements are affected by an observer's relative motion. Time measurements require specialized devices designed to account for the effects of time dilation predicted by special relativity.