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The world’s astronomers are increasingly probing the mystery of where the enormous magnetic fields that permeate our universe come from –from Earth to Mars to the Milky Way to intergalactic voids and beyond to the darkest, most remote regions of the cosmos.
The Death of Mars
A half a billion years ago, Mars magnetic field that protected an ocean as deep as the Mediterranean Sea was switched off. An impact basin deep enough to swallow Mount Everest in Valles Marineris reveals what might be the results of ancient asteroid the size of Pluto colliding with the Red Planet switching off its magnetic field, bathing the Red Planet in harmful radiation, and eroding its atmosphere by particles streaming from solar winds. Today, Mars is a frigid desert world with a carbon dioxide atmosphere 100 times thinner than Earth’s.
A strong magnetic field had probably played an important role in protecting the atmosphere from the solar wind and keeping the planet wet and habitable. “Venus and Mars have negligible magnetic fields and do not support life, while Earth’s magnetic field is relatively strong and does,” said Sarah McIntyre at Australia National University. “We find most detected exoplanets have very weak magnetic fields, so this is an important factor when searching for potentially habitable planets.”
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