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At the equator, Earth's rotation carries you eastward at more than 1,600 kilometres an hour, yet you feel nothing at all.

Astronomy (Earth's rotation)

Science

The story behind the card

People feel acceleration, not steady speed. Earth turns so smoothly that you, the buildings around you and the air itself all move together, just as you can pour a drink calmly on a plane cruising at 900 kilometres an hour. The speed depends on where you stand: a full turn takes about 24 hours at every latitude, but places nearer the poles travel round a smaller circle. In London the ground moves at about 1,040 kilometres an hour, in Istanbul about 1,260, and at the poles hardly at all. The spin still leaves traces. It makes the planet bulge slightly at the equator, and it deflects winds and ocean currents sideways, the Coriolis effect, named after the French scientist Gaspard-Gustave de Coriolis; this is why hurricanes turn in opposite directions in the two hemispheres.

Türkçe oku
Dünya'nın dönüşü, ekvatorda duran birini saatte 1.600 kilometreyi aşkın bir hızla doğuya taşır; ama bu hız hiç hissedilmez.

İnsan sabit hızı değil, hızlanmayı ve yavaşlamayı hisseder. Dünya o kadar düzgün döner ki siz, çevrenizdeki binalar ve hava hep birlikte hareket edersiniz; tıpkı saatte 900 kilometreyle giden bir uçakta bardağa rahatça su doldurabilmeniz gibi. Hız, bulunduğunuz yere göre değişir: Tam bir tur her enlemde yaklaşık 24 saat sürer, ama kutuplara yakın yerler daha küçük bir çember çizer. Londra'da yer saatte yaklaşık 1.040 kilometre, İstanbul'da yaklaşık 1.260 kilometre hızla hareket eder; kutuplarda ise neredeyse hiç hareket etmez. Dönüşün izleri yine de görülür. Dünya ekvatorda hafifçe şişkindir; rüzgârlar ve okyanus akıntıları da yana doğru sapar. Adını Fransız bilim insanı Gaspard-Gustave de Coriolis'ten alan bu Coriolis etkisi yüzünden kasırgalar iki yarımkürede ters yönlerde döner.

Sources and further reading

Background reading: Earth's rotation
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