Mt Verde, Cape Verde

I am sitting on top of Monte Verde overlooking the Atlantic. With an elevation of 750 m (2,460 ft) it is the tallest mountain in the Cape Verde archipelago. From up here, how far is it to the horizon way out in the Atlantic Ocean? A) 49 km  B) 108 km  C) 220 km or D) 312 km (check for the correct answer at the bottom of this page).

Here is another question that puzzled me: with close to 60,000 merchant ships plowing the oceans globally, it is amazing how long you can cross the oceans without noticing any other vessel. Last year I sailed from Lima to Auckland – 12 days of crossing over 10,000 km (6,000 mi) across the beautiful Pacific Ocean. While at sea, we did not spot one single ship. You can thank the curvature of earth for such solitude. If you were to stand on a ship’s deck 5 m (16 ft) above the water, the horizon’s edge would only be 8 km (5 mi) away in each direction. Even in oceans crowded with marine traffic, you can feel alone. The other ships are below the horizon and out of sight.

You have to have a peculiar mind to think about these things instead of enjoying the view. From a very young age on I have been fascinated with the sea. Growing up in the industrial town of Bochum in Germany, far away from saltwater, the vast oceans held so much mystery for me. But considering that oceans cover 71 percent of the earth’s surface, I should really know a lot more about them. Oceans feed us, give us our climate, provide us with drinking water, are a highway for transporting goods and are home to an estimated 2 million marine species (of which 230,000 are known to science).

Marine science knows a lot about the world’s oceans but there is so much more we don’t know. Oceanographers believe only 5 percent of the world’s oceans have been explored thus far. The thought of marine life existing in the depth of the ocean where no human has ever travelled before, fascinates me. Why are we flying off to Mars when so much more is left to be explored on earth?

The world’s oceans are truly immense. With over 166 million sqkm (64 million sqmi) the Pacific is by far the largest body of water. The Pacific is almost as big as the Atlantic, the Indian and the Arctic Oceans combined. But even more amazing are the depth of the oceans and the volume of water they contain. All three, the Pacific, the Atlantic and the Indian oceans have an average depth of well over 3.5 km (2.2 mi). At a depth of 1 km (3,000 ft), the underwater pressure is sufficient to squeeze a block of wood to one-half of its volume. It would no longer float.

It is estimated that the total volume of water held by all of the world’s oceans is 1,367 million cubic km (328 million cubic miles). So, what would happen if we took all of the world’s landmass and ocean floor and completely levelled it – no mountains, no deep ocean trenches, just smooth solid earth all around the globe? Given that all land above sea level only adds up to 1/18th of the volume of all oceans, a levelled earth would still be covered by over 3.6 km (12,000 ft) of water.

Ok, now that you are sufficiently impressed by the world’s oceans, lets do some math: Ignoring the effects of atmosphereic refraction, the distance to the horizon in km is 3.57 x sq root of the height above sea level in meters (750 m). Therefore, the correct answer is B. From the top of Monte Verde I was able to see the horizon at a distance of  108 km (65 mi).

~ RT