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Why the moon’s early magnetic field might be responsible for life on earth

The habitability of a planet depends on many factors. One is the existence of a strong and long-lived magnetic field. These fields are generated thousands of kilometers below the planet’s surface in its liquid core and extend far into space – shielding the atmosphere from harmful solar radiation. Without a strong magnetic field, a planet struggles to hang on to a breathable atmosphere – which is bad news for life as we know it. A new study, published in Science Advances, suggests that the Moon’s now extinct magnetic field may have helped protect our planet’s atmosphere as life was forming around 4 billion years ago. Today, Earth has a strong global magnetic field that protects the atmosphere and low-orbiting satellites from harsh solar radiation. In contrast, the Moon does not possess either a breathable atmosphere or a global magnetic field. Global magnetic fields are generated by the motion of molten iron in the cores of planets and moons. Keeping the fluid moving requires energy, such as heat trapped within the core. When there is insufficient energy, the field dies. Without a global magnetic field, the charged particles of the solar wind (radiation from the Sun) passing close to a planet generate electric fields that can accelerate charged atoms, known as ions, out of the atmosphere. This process is happening today on Mars and it is losing oxygen as a result – something that has been directly measured by the Mars atmosphere and volatile evolution (Maven) mission. The solar wind can…Continue readingWhy the moon’s early magnetic field might be responsible for life on earth

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The Moon’s surface is rusting — and Earth may be to blame

Oh, hiding away, eh? The solar wind delivers hydrogen, usually discouraging the oxidation of iron into hematite on the lunar surface. However, each full moon finds our planetary companion behind the Earth, where it is protected from the solar wind. These monthly reprieves from the bombardment of hydrogen creates periodic times when oxygen can react with iron, producing hematite, researchers theorized. “The lack of atmosphere on the Moon allows solar wind (most of which is [hydrogen]) to reach the lunar surface and be implanted into the top tens to hundreds of nanometers of layer of surface grains,” researchers describe in an article published in the journal Science Advances. When oxidation nibbles more slowly — more delicately, like a tortoise — at the world around us, without a flame, we call it rust and we sometimes scarcely notice as it goes about its business consuming everything from hairpins to whole civilizations. ― Alan Bradley, A Red Herring Without Mustard The Chandrayaan-1 spacecraft undergoing testing prior to launch. Image credit: ISRO The other critical ingredient for rust is water. And, although the Moon possesses water ice at its poles, these hematite deposits were separated from these lunar glaciers. Investigators suggest water on the surface of the Moon may be kicked up by fast-moving dust particles traveling through space. When this occurs when the Moon is shielded by Earth, hematite could, potentially, form. This new study might also suggest how water found on other small, airless bodies like asteroids may have been created. “It could be that…Continue readingThe Moon’s surface is rusting — and Earth may be to blame