Visual looming syndrome "fear of pointy objects hitting the eye", "weird sensation behind the eyes", "difficulty in focusing on objects nearby, which are moving and are not operated by the observer, such as windscreen wipers or a pencil someone else is holding". In these studies visual looming syndrome is often referred as sharp edges eye syndrome (SEES). "Looming" is a term used in the study of the perception, as it relates directly to psychology. Looming refers to the rapid expansion in the size of any given image. As the image becomes increasingly large on the perceiver's retina, i.e., when an object "looms", there
Propagation of light in non-inertial reference frames c. <br> In an inertial frame an observer cannot detect their motion via light signals as the speed of light in a vacuum is constant. This means an observer can detect when their motion is accelerated by studying light signals. <br> Propagation of light in non-inertial reference frames The description of motion in relativity requires more than one concept of speed. Coordinate speed is the coordinate distance measured by the observer divided by the coordinate time of the observer. Proper speed is the local proper distance divided by the local proper time. For example, at the event horizon of a