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
Distance measures (cosmology) have angular size formula_27 has the angular diameter distance of formula_33. This is commonly used to observe so called standard rulers, for example in the context of baryon acoustic oscillations. If the intrinsic luminosity formula_34 of a distant object is known, we can calculate its luminosity distance by measuring the flux formula_35 and determine formula_36, which turns out to be equivalent to the expression above for formula_37. This quantity is important for measurements of standard candles like type Ia supernovae, which were first used to discover the acceleration of the expansion of the universe. This distance is the time (in