light time
- noun
- /laɪt taɪm/
- Specialized
:
tiempo de luz
- To understand the vastness of space, we often express distances in terms of light time, such as light minutes or light hours.
Examples
-
Astronomers measure light time to determine how far away celestial objects are in the universe.
-
The star is located four light years away, which means it is a distance of four light time from Earth.
-
That should take care of the light time.
Fiction book (1999)
Synonyms
109
4.9
The distance light travels in one year
1
8.1
The distance light travels in one minute in empty space
The distance light travels in one second in empty space, about 300,000 kilometers
The distance light travels in empty space in one hour, about one billion kilometers
How Far
- Specialized
109
4.9
- Specialized
- Specialized
- Specialized
1
8.1
- Specialized
Surface Forms
Morphology
The compound 'light time' is compositionally built from 'light' + 'time', so learners can guess it has something to do with time related to light; this gives a partial clue. However, the precise technical sense—using the time light/radio waves take to travel as a distance-measure—is specialized and easily misinterpreted (e.g., as 'daylight' or a general time when it is light), so the meaning is not fully predictable to a B1 learner without context or prior exposure.
Etymology
The noun light time comes from the simple idea of measuring how long light takes to travel from one place to another. Space scientists use that travel time as a quick way to talk about 'distance' or the 'delay' in signals, so the light time between two points tells you how far apart they are and how long a message will take.