The fall of one of the four meteorological and astronomical seasons is the season between summer and winter. In the temperate zones, it is the time of harvest and the leaves fall. In the fall of the northern hemisphere the sun moves apparently the celestial equator to the Tropic of Capricorn.
The word autumn has etymologically the same origin as the English word harvest " crop ( time ) ", "pick" Latin and Greek carpere karpos "fruit, yield ," also lithuanian kirpti "cut", Greek krōpíon " sickle ". Originally, the word meant so fall " harvest time ". This agricultural importance has been preserved in English, while they shifted in the German general designation of the season. In the southwest German speaking country, the original meaning of the word as a dialect or technical term for the ( wine ) lives read on: this activity is widespread there with " bitterest " means.
Depending on whether the fall sway to the southern or the northern hemisphere, a distinction is made between Südherbst and northern autumn. Due to the migratory zenith position of the sun between southern and northern tropic, the autumn repeatedly in each hemisphere with an annual cycle. It is therefore possible to infer from a Südherbst a northern spring and vice versa.
Astronomically, it begins with the autumn equinox:
- In the northern hemisphere on 22 or September 23,
- In the southern hemisphere on 20 March or on the night of March 21,
- And ends with the winter solstice ( 21 or 22 December in the northern hemisphere, or on June 21 in the south)
Since the orbit of the Earth around the Sun by 1.7 percentage deviates from a circular path, the four seasons are not quite the same length. This also has something on the phenological autumn start from, which may differ from the astronomical climate. A distinction is made between the early autumn, full autumn and late autumn.
Approached be allocated to the autumn months of September, October and November in the northern hemisphere, and March, April and May in the southern hemisphere.
In autumn the leaves turn on the trees before they fall off then. Cause is the slow retreat of the plant juices in the stem and in the roots. The chlorophyll is degraded and other leaf pigments provide the colorful coloring. These dyes are, for example, carotenoids and anthocyanins. In part they are already present in the leaf, sometimes they are re- formed, so with the anthocyanins. The dyes have a protective function from the sunlight so that the juices present in the sheet can be transferred to the stem before it finally drops.
In the autumn falls in some countries of the world, the conversion of time from the summer to the normal time.
- Ru Shou
- Thanksgiving or Thanksgiving
- Reformation Day
- All Saints' Day
- St. Martin
- Sukkot, the Jewish Feast of Tabernacles
Hardly a natural motif has been treated so often in poetry as autumn. As an example, see Rainer Maria Rilke's fall.