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地球自轉一周並不是24小時……它多的是不知道的冷知識

了解地球

先從那些你不知道的地球冷知識開始吧~

1

地球不是圓的

許多人認為地球是一個球體。事實上,其形狀類似於球體,但兩極是扁平的,赤道是凸出的,這個凸起是由於地球的自轉造成的。這意味著從一極到另一極的測量距離大約比地球穿過赤道的直徑小43公里。

Many people tend to think that the Earth is a sphere. In fact, its shape is similar to a sphere, but where the poles are flattened and the equator bulges. This bulge is due to our planet's rotation. This means that the measurement from pole to pole is about 43 km less than the diameter of Earth across the equator.

死海是陸地的最低點

陸地上的最低點相對容易到達,即約旦、以色列和約旦河西岸之間的死海。這個超鹹湖的表面低於海平面1388英尺(423米)。

The lowest point on land is relatively accessible. It's the Dead Sea between Jordan, Israel and the West Bank. The surface of this super-salty lake is 1,388 feet (423 m) below sea level.

地球曾經是紫色的

馬裡蘭大學的微生物遺傳學家Shil DasSarma認為,今天地球上的生命是綠色的,但在早期可能是紫色的。他說,古代的微生物可能使用了葉綠素以外的分子來利用太陽光線,而正是這種分子賦予了生物體紫色的色彩。

It used to be purple … well, life on early Earth may have been just as purple as it is green today, suspects Shil DasSarma, a microbial geneticist at the University of Maryland. Ancient microbes, he said, might have used a molecule other than chlorophyll to harness the sun's rays, one that gave the organisms a violet hue, he suggests.

地球的大氣層能延伸到一萬公里

地球的大氣層在距離地表50公里以內是最厚的,但它實際上達到了1萬公里。它由對流層、平流層、中間層、熱層和外層五層組成。通常,空氣壓力和密度會隨著高度的升高而逐漸降低。

Earth's atmosphere is thickest within the first 50 km from the surface or so, but it actually reaches out to about 10,000 km into space. It is made up of five main layers – the Troposphere, the Stratosphere, the Mesosphere, the Thermosphere, and the Exosphere. As a rule, air pressure and density decrease the higher one goes into the atmosphere and the farther one is from the surface.

地球自轉一周不需要24小時

實際上,地球自轉一周需要23小時56分4秒,天文學家稱之為恆星日。但同時,地球繞太陽公轉。每一天,太陽與背景恆星之間的移動幅度約為1°——與天空中月亮的大小差不多。由於地球也繞著太陽轉,如果把來自太陽的小運動加起來,總共是24小時,這就是所謂的太陽日。太陽日是太陽連續兩次經過同一子午線的時間間隔。

It actually takes 23 hours, 56 minutes and 4 seconds for the Earth to rotate once completely on its axis, which astronomers refer to as a Sidereal Day. But the Earth orbits around the Sun. Every day, the Sun moves compared to the background stars by about 1° – about the size of the Moon in the sky. And so, if you add up that little motion from the Sun that we see because the Earth is orbiting around it, as well as the rotation on its axis, you get a total of 24 hours.This is what is known as a Solar Day, which – contrary to a Sidereal Day – is the amount of time it takes the Sun to return to the same place in the sky.

南極洲是一個極端的大陸

南極大陸是一個極端的地方,儘管它只是第五大大陸,但其南極冰蓋包含了地球上70%的淡水和90%的冰。或許你不知道,大家往往認為南極洲是沙漠,其內陸地區每年的降水量只有2英寸(50毫米)(當然,通常是雪)。

The southern continent is a place of extremes, with the Antarctic ice cap containing some 70 percent of Earth's fresh water and about 90 percent of its ice, even though it is only the fifth largest continent. Did you know Antarctica is actually considered a desert? Inner regions get just 2 inches (50 millimeters) of precipitation a year (typically as snow, of course).

珊瑚礁是最龐大的生物結構

珊瑚礁是地球上物種生存密度最高的生態系統,可以與雨林相媲美。美國國家海洋和大氣管理局表示,雖然珊瑚礁是由微小的珊瑚蟲組成,但它們是地球上最龐大的生物結構——一個由相互聯繫的有機體組成的群落——有些甚至可以從太空中看到。

Coral reefs support the most species per unit area of any of the planet's ecosystems, rivaling rain forests. And while they are made up of tiny coral polyps, together coral reefs are the largest living structures on Earth — a community of connected organisms — with some visible even from space, according to NOAA.

來源:中國日報,旨在分享,如有侵權,聯繫刪除。

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