If we observe the Earth from space, sometimes what seems to be a column of smoke or an incandescent glow appear suddenly from a specific point on the planet. These are volcanoes which awaken and erupted on the surface, expelling dust and lava from the bowels of the planet: one of the many phenomena that demonstrates the vitality of our world and the processes that continue to develop in the interior of our world. It is just these processes which cause the Earth to act like an enormous magnetic aligned along a north-south axis. The flow of heat in its molten core produces electric currents similar to those of an electric magnet: these are the currents which generate the magnetic field that protects us from the most dangerous types of solar radiation. In fact, the force lines extend well beyond the outer layers of the atmosphere, and so much so that the far limit of the magnetic field, or magnetopause, is located at a distance that varies from 64 000 to 130 000 kilometers from the Earth. Today, the north and south magnetic poles coincide approximately with the geographic north and south poles, but this has not always been the case. By studying the composition of the rocks which have retained traces of the ancient magnetism since their creation, geologists have not only discovered that 700 000 years ago the magnetic norh pole was located where the south pole is today, but that this inversion in polarity has occurred many times over the last three billion years. But now it is time to leave the Earth and head towards our satellite; a world that, unlike our own, has not changed for the last two billion years and therefore can help us to better understand the history of our own past.
If we observe the Earth from space, sometimes what seems to be a column of smoke or an incandescent glow appear suddenly from a specific point on the planet. These are volcanoes which awaken and erupted on the surface, expelling dust and lava from the bowels of the planet: one of the many phenomena that demonstrates the vitality of our world and the processes that continue to develop in the interior of our world. It is just these processes which cause the Earth to act like an enormous magnetic aligned along a north-south axis. The flow of heat in its molten core produces electric currents similar to those of an electric magnet: these are the currents which generate the magnetic field that protects us from the most dangerous types of solar radiation. In fact, the force lines extend well beyond the outer layers of the atmosphere, and so much so that the far limit of the magnetic field, or magnetopause, is located at a distance that varies from 64 000 to 130 000 kilometers from the Earth. Today, the north and south magnetic poles coincide approximately with the geographic north and south poles, but this has not always been the case. By studying the composition of the rocks which have retained traces of the ancient magnetism since their creation, geologists have not only discovered that 700 000 years ago the magnetic norh pole was located where the south pole is today, but that this inversion in polarity has occurred many times over the last three billion years. But now it is time to leave the Earth and head towards our satellite; a world that, unlike our own, has not changed for the last two billion years and therefore can help us to better understand the history of our own past.
