AskDefine | Define daylight

Dictionary Definition

daylight

Noun

1 the time after sunrise and before sunset while it is light outside; "the dawn turned night into day"; "it is easier to make the repairs in the daytime" [syn: day, daytime] [ant: night]
2 light during the daytime

User Contributed Dictionary

see daylights

English

Etymology

From day + light

Noun

  1. The light from the Sun, as opposed to that from any other source.
  2. A light source that simulates daylight.
  3. countable photometry The intensity distribution of light over the visible spectrum generated by the Sun under various conditions or by other light sources intended to simulate natural daylight.
  4. The period of time between sunrise and sunset.
    We should get home while it's still daylight.
  5. Daybreak.
    We had only two hours to work before daylight.
  6. Exposure to public scrutiny.
    Budgeting a spy organization can't very well be done in daylight.
  7. A clear, open space.
    All small running backs instinctively run to daylight.
    He could barely see daylight through the complex clockwork.
    Finally, after weeks of work on the project, they could see daylight.
  8. countable machinery The space between platens on a press or similar machinery.
    The minimum and maximum daylights on an injection molding machine determines the sizes of the items it can make.

Antonyms

Synonyms

Translations

light from the sun
period of time between sunrise and sunset

Verb

  1. To expose to daylight
  2. To provide sources of natural illumination such as skylights or windows.
  3. To allow light in, as by drawing drapes.
  4. In the context of "landscaping|civil engineering": To run a drainage pipe to an opening from which its contents can drain away naturally.
  5. To gain exposure to the open.
    The seam of coal daylighted at a cliff by the river.

See also

Extensive Definition

Daylight or the light of day is the combination of all direct and indirect sunlight outdoors during the daytime (and perhaps twilight). This includes direct sunlight, diffuse sky radiation, and (often) both of these reflected from the Earth and terrestrial objects. Sunlight scattered or reflected from objects in outer space (that is, beyond the Earth's atmosphere) is generally not considered daylight. Thus, moonlight is never considered daylight, despite being "indirect sunlight". Daytime is the period of time each day when daylight occurs.

Definition

Daylight is present at a particular location, to some degree, whenever the sun is above the horizon at that location. (This is true for slightly more than 50% of the Earth at any given time, for an explantion of why it is not exactly half, see the section labeled "introduction" on the day article). However, the outdoor illuminance can vary from 120,000 lux for direct sunlight at noon, which may cause eye pain, to less than 5 lux for thick storm clouds with the sun at the horizon (even <1 lux for the most extreme case), which may make shadows from distant street lights visible. It may be darker under unusual circumstances such as a solar eclipse or very high levels of atmospheric smoke.

Daylight intensity in different conditions

For comparison, nighttime illuminance levels are:

Daylight intensity in the Solar System

Different bodies of the Solar System receive light proportionally to the square of their distance from Sun. A rough table comparing the amount of light received by each planet on the Solar System (and the dwarf planets Ceres and Pluto) follows (from data in http://www.starhop.com/High/SolInt-19.pdf):
The actual brightness of daylight that would be observed at the surface depends also on the presence and composition of an atmosphere. For example Venus' thick atmosphere reflects up to 60% of the solar light it receives, so the actual illumination of the surface is comparable to that of Earth.
For comparison purposes, daylight on Saturn is somewhat slightly brighter than Earth daylight on the average sunset or sunrise. Even on Pluto the Sun would be still bright enough to almost match the average living room. To see the Sun shine as dim as the full Moon on the Earth, a distance of about 500 AU is needed: there is only a handful of objects in the solar system known to orbit farther than such a distance, among them 90377 Sedna and (87269) 2000 OO67.

Notes

External links

daylight in Danish: sollys
daylight in Dutch: Daglicht
daylight in Swedish: Dagsljus

Synonyms, Antonyms and Related Words

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