It’s like finding out some fascinating little secrets about your own mother.
This year, our life-giver, the Blue Planet, revealed a host of details about herself. We learned where to find the clearest seas, the oldest piece of the Earth’s crust, why it hums, and how many volcanoes sit on the ocean floor. We now know how the weather makes the days a tiny bit longer, while climate change will make them shorter. Oh, and Earth is smaller than we thought.
The planet’s clearest ocean waters lie in the middle of the southern Pacific. A lack of chlorophyll and nutrients also makes them the most lifeless, giving them an eerie violet hue that can be picked out from space. The record-breaking crust, at 3.8 billion years old, was found in Greenland.
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As for that mysterious hum, computer models show it is caused by turbulent water pounding the ocean floor. A review of sonar data reveals there are more than 200,000 undersea volcanoes, 10 times the number expected. Most were too small to have been detected before.
In June, new video technology revealed sprites in their full glory as these gigantic flashes of light tear through the thin air above thunderclouds. A new type of polar aurora was also revealed, thought to be caused by electrons from the solar wind reaching a different part of the atmosphere from the source of most auroras.
Why do El Niño events make the days a wee bit longer? It’s because they generate strong westerly winds that speed up the rotation of the atmosphere. The Earth and its atmosphere system always retain the same total angular momentum, so Earth has to slow down to compensate, adding roughly 1 millisecond to each day during an El Niño. That will partly be offset by climate change, as warmer oceans will shift some of the mass of the oceans towards the poles. Like an ice skater tucking her arms into her body, the Earth will spin faster, losing 2.3 milliseconds every 100 years.
What of our planet’s size? A new, more precise measurement of her diameter revealed she is 5 millimetres smaller than we thought.
