Every year thousands of islands, made solely of ice, break away from the glaciers of the Arctic and Antarctic Wastes. Alone Greenland produces more than 40,000 of them. From there they embark on a journey, which could take them more than 15,000 kilometers away, until the warmer waters finally reduce them to nothing more than simple ice cubes. They fill the oceans around the North and South Pole, creating an everchanging maze and pose a constant threat for the ships, brave enough to navigate through them. This was a risk, which captains are well aware of and have been long before the Titanic met its tragic fate.
Even with modern technology like radars and GPS tracking, icebergs are notoriously difficult to detect. The non-stop movement of water can hide even the largest ones – a one-meter wave is enough to obscure the tip of an iceberg up to seven meters tall. Even on a clear day, when a captain has a direct line of sight, it’s still largely a game of guessing, as more than 90% of the ice lies underwater. These things are massive and very unpredictable. The largest iceberg ever recorder was a whopping 335 km long and 97km wide, covering an area larger than Belgium. And as if that alone isn’t enough, they are also incredibly hard. While the outer layer keeps melting, the inside core remains at around -20 degrees Celsius.
The enormous pressure of millions of tons of ice over thousands of years packs the molecules inside the ice crystals very tightly together, so much so that drilling deeper than 30 meters requires special equipment. Another side effect of the constant melting is that the weight distribution inside is constantly changing and at any given point the center of gravity can shift, causing it to topple. This releases a huge amount of energy, equal to a magnitude 5 earthquake and has been known to even cause tsunamis.
The pristine white color of icebergs is caused by countless small air bubbles, trapped within the ice. They are formed by the very long and immensely powerful compression, exercised within glaciers. These bubbles reflect light in all directions, creating the white color. Very often there a blue streaks crossing it, which are formed when seawater freezes. Sometimes different organisms get trapped within the ice, which can give it a red, yellow or greenish tint. And very rarely, a piece of pure ice forms, without any imperfections. These pieces don’t scatter light at all and so appear black.