對于覆蓋了地球表面絕大部分的海洋我們了解多少？都說人類對月球的了解要比對海洋深度的了解要多得多。確實(shí)，對于覆蓋地球表面大部分區(qū)域的 H2O，我們真是知之甚少。首先，你知道它有多深么？
It’s often said we know more about the moon than we do about the depths of the ocean. There is a lot we don’t know about the H2O that covers much of the planet. Now we’re getting closer, though, to an important understanding: Just how deep are the oceans, and what’s the volume of all that water? The latest, best estimate is 1.332 billion cubic kilometers, according to research published in the journal Oceanography. That’s actually lower than previous estimates by about five Gulf of Mexicos. It’s not that there’s less water out there. Rather, new satelite images have presented a clearer image of all the mountain ranges strewn across the ocean floor. Those peaks displace what we’d thought of as space for water. But even the new satellite-based radar images still need fine-tuning. As researcher Walter Smith says, “We’re seeing only really big mountains, and in a blurry way. The resolution is 15 times worse than our maps of Mars and the moon.” Ship-based sonar would help, but ship-based instruments have mapped only about 10 percent of the ocean floor so far. We really do know more about the surface of the moon than the total ocean floor.
都說人類對月球的了解要比對海洋深度的了解要多得多。確實(shí)，對于覆蓋地球表面大部分區(qū)域的 H2O，我們真是知之甚少。不過，我們正越來越接近相當(dāng)重要的發(fā)現(xiàn)：海洋到底有多深？它的總水量又是多少？據(jù)《海洋學(xué)》相關(guān)研究記載，最新最準(zhǔn)確的估計，海洋總水量為13.32億立方千米。 這個數(shù)據(jù)要比之前所估計的大約要小5個墨西哥灣的水量，但這并不表示水少了。事實(shí)上，從最新衛(wèi)星圖像中我們可以看到更加清晰的海底山脈分布情況，這些山脈分布的地方之前也被當(dāng)成了海水。 不過即使是新型衛(wèi)星雷達(dá)圖像仍有待調(diào)整。正如沃特·史密斯所說：“我們看到的只是大型山脈，還模模糊糊的。分辨率要比火星和月球的衛(wèi)星圖像低15倍?！?盡管船舶聲納技術(shù)也用得上，但是迄今為止利用船舶器械僅僅繪制出海底地貌的10%。看來，我們對月球表面的了解確實(shí)要比對海底地貌的了解要多得多啊。