We see that the variation of the length of day
and month is a manifestation of the changing conditions (perturbation) of the Earth which are parameterized as a function of time (t) only.
The famous clock on Prague's Old Town City Hall (1410), for example, possesses a dial with an astrolabe notably displaying the length of day
and night, solar time, sidereal time, the signs of the Zodiac and the apparent movements of the sun and moon.
Doha is approximately 2800km (1740 miles) from the equator, and even here there is already a noticeable difference in the length of day
between summer and winter.
Scientists have long known that the earth's rotation rate, which determines the length of day
, can be sped up or slowed down by winds blowing on mountains.
Pity the houseplants, as many of them are native to the equatorial areas of the world, where the length of day
and of night remains nearly equal year-round.
After incorporating newly available stratospheric wind data, the meteorologists conclude that "tropospheric plus stratospheric winds can fully account for seasonal, nontidal changes in the length of day
[or rotation rate] without invoking other geophysical processes."
This is the same length of day
as last year on Oct.
The length of day
today is 10 hours and 46 minutes.
As all of nature responds to the length of day
as well as temperature, it is apparent that lack of light has a limiting effect on both people and plants.
Life on Earth gets its cue of the changing weather from the length of days
The length of days
keeps decreasing per day as northern hemisphere tilts away from the sun after the summer solstice and the heat associated with this period is trapped by our oceans and atmosphere.
SIR - Barry Taylor (Letters, Dec 4) is quite right that you can have a non Christian mid winter festival to cheer up the bleak season or look forward to an increase in the length of days
- many societies have had that custom.