Your friend, the magnet
Imagine there would be no magnetic field around Earth. Well, so what? The clever boy scout wouldn’t be able to find his way out of a forest because the needle of his compass would simply point somewhere at random. Also, we wouldn’t know where the north pole is exactly. But apart from that? Magnetism is one of the four major forces of nature, and it’s always there. Just like gravity. We take it for granted, and it’s simply part of life. As long as it’s there. But what would happen if it vanished?
What sounds like science fiction has in fact happened lots of times in Earth’s history. Earth’s magnetic field would then simply disappear and the magnetic poles would show up again in entirely different places. During the course of a million years north and south pole switch positions twice. A process that takes thousands of years during which the polarisation of Earth’s magnetic field is undefined. In the early days of flight no plane would ever have reached its destination without a compass. And today, in the presence of GPS, a weakening magnetic field poses a threat to navigation again, because the signals become too noisy. This happens over and over again at the coast of Brazil – without anyone knowing what’s actually going on there.
We have to admit: What we know about Earth’s magnetic field is very little. We hardly now anything about how it changes and what happens when it does. We get an idea by having a look at Mars, a planet that has lost its magnetic field almost entirely. And with it it has lost its atmosphere, and its water. Will we have to face the same fate? To find an answer to that question, and many more, ESA* sends three satellites on a mission around Earth. They are going to measure even the slightest changes and anomalities in Earth’s magnetic field. And while this is a tremendous effort it’s still more precise, faster and cheaper than any other method. Launch date is October 4, 2013, and scientists hope to soon have enough data to create models on what our future will look like: how our climate will change, whether or not navigation signals will be corrupted, or maybe if there will be new sources of raw materials. Who would have thought that space would be so important in identifying and solving problems down here on earth?
*The European Space Agency ESA is a joint organization of 20 countries.