According to the principles of special relativity, the length of an object does appear to change when measured from different reference frames, but this effect is not the cause of length contraction. Let me explain further.
In special relativity, there is a phenomenon known as length contraction or Lorentz contraction. It states that when an object is moving relative to an observer, its length appears shorter in the direction of motion as compared to its length at rest.
However, it's important to note that length contraction is not due to an actual physical compression of the object. Instead, it arises from the nature of spacetime itself. Special relativity introduces the concept of spacetime as a unified four-dimensional framework where space and time are interconnected.
In this framework, different observers moving relative to each other will experience different measurements of both space and time. The way distances and durations are perceived by observers depends on their relative motion. This is described by the Lorentz transformation equations, which govern how quantities such as length, time, and velocity change between reference frames.
In the case of length contraction, the observer in a particular reference frame measures the length of a moving object to be shorter along the direction of motion compared to its rest length. However, an observer moving with the object would measure its length to be unchanged. This apparent contraction is a consequence of how the spatial and temporal coordinates transform between different reference frames.
The unit of length, such as a meter, remains constant in all reference frames. The length contraction effect arises due to the relative motion between the observer and the object being measured, as described by the Lorentz transformation equations.