Moon
From Gwn
| Earth's Moon | |
| |
| Discovered: | Always known to humanity. |
| Named After: | Named after the Roman God |
| Relative Size: | Planet Standard |
| Satellites: | Notable Satellites
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Earth (often referred to as Terra, the World or Planet Earth) is the third planet in the solar system in terms of distance from the Sun, and the fifth largest. It is also the largest of its planetary system's terrestrial planets, making it the largest solid body in the solar system, and it is the only place in the universe known to humans to support life. It is also the densest planet in the solar system.
History
The Earth formed 4.567 billion years ago out of the solar nebula, along with the Sun and the other planets. Initially molten, the outer layer of the planet cooled when water began accumulating in the atmosphere when the planet was about half its current radius, resulting in the solid crust. The moon formed soon afterwards, possibly as the result of the impact with a Mars-sized object known as Theia.
The development of photosynthesis allowed the sun's energy to be harvested directly; the resultant oxygen accumulated in the atmosphere and gave rise to the ozone layer. The incorporation of smaller cells within larger ones resulted in the development of complex cells called eukaryotes. Cells within colonies became increasingly specialized, resulting in true multicellular organisms. Aided by the absorption of harmful ultraviolet radiation by the ozone layer, life colonized the surface of Earth.
Around 535 million years ago, there have been five mass extinctions. Over the past 65 million years, mammalian life has diversified, and several mya, a small African ape gained the ability to stand upright. This enabled tool use and encouraged communication that provided the nutrition and stimulation needed for a larger brain. The development of agriculture, and then civilization, allowed humans to influence the Earth in a short timespan as no other life form had, affecting both the nature and quantity of other life forms.
Meaning of the Name
The English word "earth" has cognates in many modern and ancient languages. Examples in modern tongues include aarde in Afrikaans and Dutch, and Erde in German. The root has cognates in extinct languages such as ertha in Old Saxon and ert (meaning "ground") in Middle Irish, derived from the Old English eorðe. All of these words derive from the Proto-Indo-European base *er-.
Words for Earth in other languages include: Terre (French), पृथ्वी pr̥thvī (Sanskrit), Maa (Finnish and Estonian), Pământ (Romanian), Föld (Hungarian), Ziemia (Polish), Zemlja (Russian and Serbian), Zemya Земя (Bulgarian), Tierra (Spanish), Terra (Italian), Diqiu (Mandarin), Deiqao (Cantonese), Jigu (Korean), Bumi (Malay), Chikyuu (Japanese), Jorden (Danish, Norwegian, Swedish), כדור הארץ (Hebrew), Bhoomi (Telugu), Gi, Choma (Greek), Dunia (Swahili), Âlem, Dünya الْمَسْكُونَة (Arabic), Dinê (Kurdish), Ergir երկիր (Armenian), Jehun, Zamin (Persian), and Acun, Yeryüzü, Yerküre (Turkish).
