Final answer:
Real time refers to the current moment or actual time an event occurs, often associated with 'proper time' in physics. Proper time (Δt₀) is measured by an observer at rest relative to the event. Variation in verb tenses in English indicates whether events are in the present or past.
Step-by-step explanation:
Real time is the current moment or the actual time in which something takes place. In physics, this is often referred to as proper time, represented as Δt₀, which is the time interval measured by an observer who is at rest relative to the event being observed. Proper time is distinguished from time intervals or the duration over which events occur, which can be very different for observers in various frames of reference due to the effects of relativity.
For example, an instant in time is different from time taken or a time interval. When discussing rates of reaction in chemistry, the instantaneous rate is the rate at a particular instant of time, which can be contrasted with average rates over a period of time.
Furthermore, in every variety of English, verb tenses change to signify whether something is happening currently or has already happened, indicating time differences. Present tense is used for actions occurring in the present time, while past tense is used for actions that occurred in the past.