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Word of the week: Cosmic Magnetism

One of the key science goals of the SKA will be to study cosmic magnetism. Everybody knows about magnetism, but what about cosmic magnetism? Jimi Green, our project scientist specialising on magnetism, explains:

An image of the Sun’s corona, taken in Nov 1999 by the Transition Region and Coronal Explorer (TRACE) satellite. The giant loops of gas seen arching above the Sun’s surface delineate the patterns made by invisible magnetic fields. TRACE is a mission of the Stanford-Lockheed Institute for Space Research, and is part of the NASA Small Explorer program.

“‘Cosmic Magnetism’ refers to the magnetic fields of our universe, which are present in planets, stars, galaxies and the universe at large. They play a major role as without a magnetic field around our planet to protect us from cosmic radiation, Life would not be possible on Earth. However we do not understand where this magnetism comes from, what generated it, and what influence it has on the universe that surrounds us.

The study of cosmic magnetism is comparable to the study of common household magnets on iron filings. When approaching a magnet to a lump of iron filings, these align in a pattern delineating the shape of the magnetic field. But the cosmic magnets we study are scaled to extreme sizes, and instead of using iron filings we use radio waves emitted by celestial objects. The radio waves, in passing through magnetic fields, are affected by them and some of their properties change. We call this polarisation.

With the sensitivity of the SKA and polarised radio waves we will be able to study cosmic magnetic fields. The SKA will allow us to map these huge magnetic fields across the entire sky visible from the southern hemisphere where the telescope is located, from the magnetic fields within our galaxy out to very distant objects.”

For more information visit our Cosmic Magnetism science page.

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