No, our universe cannot exist in only one dimension. Our universe is generally described as having three spatial dimensions—length, width, and height—along with one temporal dimension, which represents the dimension of time. This framework is known as four-dimensional spacetime.
One-dimensional space refers to a system with only a single dimension, such as a straight line. In such a space, there is no width or height, only length. It is not possible for our complex universe, with its diverse structures, objects, and interactions, to exist solely within a one-dimensional space.
However, it is worth noting that certain theoretical models in physics, such as string theory or some variations of quantum gravity, propose the existence of additional compactified dimensions beyond the four we are familiar with. These models suggest that these extra dimensions may be curled up or hidden at extremely small scales, which is why we don't perceive them in our everyday experiences. Nonetheless, these extra dimensions are still necessary for these theories to describe the universe accurately.