enow.com Web Search

Search results

  1. Results from the WOW.Com Content Network
  2. Equinoctial hours - Wikipedia

    en.wikipedia.org/wiki/Equinoctial_hours

    An equinoctial hour is one of the 24 equal parts of the full day (which includes daytime and nighttime). Its length, unlike the temporal hour , does not vary with the season , but is constant. The measurement of the full day with equinoctial hours of equal length was first used about 2,400 years ago in Babylonia to make astronomical ...

  3. Equinox - Wikipedia

    en.wikipedia.org/wiki/Equinox

    These effects make the day about 14 minutes longer than the night at the equator and longer still towards the poles. The real equality of day and night only happens in places far enough from the equator to have a seasonal difference in day length of at least 7 minutes, [30] actually occurring a few days towards the winter side of each equinox ...

  4. Photoperiodism - Wikipedia

    en.wikipedia.org/wiki/Photoperiodism

    The rotation of the earth around its axis produces 24 hour changes in light (day) and dark (night) cycles on earth. The length of the light and dark in each phase varies across the seasons due to the tilt of the earth around its axis. The photoperiod defines the length of the light, for example a summer day the length of light could be 16 hours ...

  5. Diurnal cycle - Wikipedia

    en.wikipedia.org/wiki/Diurnal_cycle

    Earth's rotation relative to the Sun causes the 24-hour day/night cycle. A diurnal cycle (or diel cycle) is any pattern that recurs every 24 hours as a result of one full rotation of the planet Earth around its axis. [1] Earth's rotation causes surface temperature fluctuations throughout the day and night, as well as weather changes throughout ...

  6. Diurnal motion - Wikipedia

    en.wikipedia.org/wiki/Diurnal_motion

    The daily arc path of an object on the celestial sphere, including the possible part below the horizon, has a length proportional to the cosine of the declination.Thus, the speed of the diurnal motion of a celestial object equals this cosine times 15° per hour, 15 arcminutes per minute, or 15 arcseconds per second.

  7. Lunar day - Wikipedia

    en.wikipedia.org/wiki/Lunar_day

    A lunar day is the time it takes for Earth's Moon to complete on its axis one synodic rotation, meaning with respect to the Sun. Informally, a lunar day and a lunar night is each approx. 14 Earth days. The formal lunar day is therefore the time of a full lunar day-night cycle.

  8. Day length fluctuations - Wikipedia

    en.wikipedia.org/wiki/Day_length_fluctuations

    The length of the day (LOD), which has increased over the long term of Earth's history due to tidal effects, is also subject to fluctuations on a shorter scale of time. Exact measurements of time by atomic clocks and satellite laser ranging have revealed that the LOD is subject to a number of different changes.

  9. Moonrise and moonset - Wikipedia

    en.wikipedia.org/wiki/Moonrise_and_moonset

    A waning gibbous is best seen from late night to early morning. [6] The Moon rises 30 to 70 minutes (should be a fixed number, about 50 minutes, if it's the same 13 degrees) later each day/night than the day/night before, due to the fact that the Moon moves 13 degrees every day. Hence, the Earth must move 13 degrees after completing one ...