However, in the outermost part of the core the propagation is faster also when parallel to the rotation axis, but the slower direction is just in the plane of the equator, at 90 degrees. Those passing through the innermost part of the core travel a few seconds faster if they run parallel to the Earth’s axis of rotation than if they run in a 50-degree plane, for example. The data show that the waves do not propagate uniformly. These seismic waves make it possible to study the composition of the inner core with an “unprecedented” level of detail, according to the researchers.Īll these earthquake rebounds were recorded at hundreds of seismic stations across all continents. This is a type of signal that was in the archives, but that no one had analyzed before. Almost 90 years later, the same principle, with much more advanced technology, has made it possible to identify 16 earthquakes among the 200 analyzed that passed through the inner core, not once, but twice, three, four and even five times. In 1936, Danish seismology pioneer Inge Lehmann discovered the Earth’s inner core by studying the propagation velocity of earthquakes that crossed the planet from side to side, passing through the core once. That won’t happen for billions of years, but it’s also interesting to understand planets very similar to Earth that have lost their magnetic shield, like Mars. Understanding the interior of the core is essential to knowing how our planet formed and when it will cease to be a habitable place once the outer core completely solidifies and the magnetic field that protects it from space radiation disappears. “If we could dismantle the planet by removing the mantle and the liquid outer core, we would see that the inner core shines like a star,” explained Hrvoje Tkalčić, a geophysicist at the Australian National University and author of the study on the innermost layer of Earth, published on Tuesday in Nature Communications. The pressure is three million times higher than on the surface and the temperature is around 5,500 degrees Celsius (9,932 degrees Fahrenheit). The inner core of our planet would be unrecognizable to any inhabitant of Earth. Now, an analysis of more than 200 earthquakes in the last decade confirms that the inner core contains a fifth, even more internal layer: a sphere of almost pure iron with a radius of 650 kilometers, almost 404 miles. Just as suddenly, the stereo is turned off and silence reigns again.For decades, textbooks have taught us that the Earth is like a Russian doll containing four main layers, one inside the other: crust, mantle, outer core, and inner core. The deep voices fill us with a sense of belonging to something bigger than Mother Earth. We have grown used to them but when we listen and let the sounds penetrate our being, we feel we are part of something ancient and sacred, even though we don’t understand a word and are not religious. The clear and passionate cries echo through the valley. As is common as well, it is quickly followed by a second. After the typical crackling of the sound system, the call to prayer comes wailing through the air. Jordan hasn’t ‘discovered’ boom boxes yet and in this country, villages can actually still be silent. Coen is drawing, sitting in one of the openings in the wall, I am jotting down notes, sitting on the remains of another wall (while keeping a fly away from my nose). The Palace of the Slave – Qatar al Abid – is a Hellenistic site in the center of Iraq al Amir. Wild Camp near Ajlun Day 13, 156 kms, Iraq al Amir I don’t care for smoking at all but I see the charm of smoking a water pipe. Here sat a highly content man, in good company, with a full belly and his water pipe. Afterwards, he showed me how a shisha works while Arafat filled it with fresh tobacco and topped it with 3 glowing pieces of charcoal. Lunch was the reason to set his water pipe aside for a bit, which Tariq had bought in Amman just for his 10-day vacation in Jordan. We joined them on the mats and cushions on the ground and devoured the delicious rice with chicken – as a hiker you can always eat more. “Come and eat with us, our Arab ways don’t allow us to let you go before you eat with us.” The fact we had just eaten our lunch was irrelevant. Tariq, a Syrian who lives in Saudi Arabia with his Kuwaitian wife Anoura, had been invited by his Jordan friend Arafat who was cooking maklubbah (translated as ‘opposite sides’ Tariq said, but it must be something like ‘upside down’ as after the cooking the meal is served upside down on a large plate). Yesterday, on our way to this town, we met a group of people picnicking outside the city.
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