How Deep Is the Ocean?大海到底有多深?(有声)
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 1 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 2 images still need fine-tuning. As researcher Walter Smith says, “We’re seeing only really big mountains, and in a blurry 3 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
- The gulf between the two leaders cannot be bridged.两位领导人之间的鸿沟难以跨越。
- There is a gulf between the two cities.这两座城市间有个海湾。
- They are following the flight of an aircraft by radar.他们正在用雷达追踪一架飞机的飞行。
- Enemy ships were detected on the radar.敌舰的影像已显现在雷达上。