How this cosmic map of magnetic fields could help illuminate one of the universe’s most mysterious forces | CSIRO
A cosmic map of magnetic fields – the largest map ever produced – could help scientists discover one of the largest and most mysterious forces in the universe.
CSIRO, a global team led by Australia’s national science agency, mapped magnetic fields by measuring light from galaxies around 4 meters across as they warp and travel through intergalactic space.
CSIRO astronomer and astrophysicist Dr. Alec Thomson said the Earth, stars, galaxies and the material between galaxies all have magnetic fields, so the map will allow scientists to investigate fundamental questions about the physics of the universe and the galaxy we live in.
“We actually still don’t know how magnetic fields started in the universe or how they’ve changed over time since the big bang. So this kind of map helps us answer those questions and look at the details of the magnetic universe.”
The encyclopedic chart now published, called “SPICE_RACS” (Spectra and Polarization in Intersections of Extragalactic Sources from the Fast ASKAP Continuum Survey), was made possible by the Australian Square Kilometer Array Pathfinder, the country’s most powerful radio telescope array, located at the Inyarrimanha Ilgari Bundara observatory in Western Australia. The device is capable of scanning large areas of the sky and the depths of the farthest reaches of distant galaxies.
Prof Naomi McClure-Griffiths, author of the paper and principal scientist at the Square Kilometer Array observatory, said previous efforts to map magnetic fields had not even covered the southern sky.
“We have been working with essentially the same data set for the last 20 years,” he said. “We can now finally answer some of the big questions by providing a much better picture of the magnetic structures of the universe.”
The data set, which is five times larger and much more detailed than previous studies, is available It is available to scientists around the world and is published by the Astronomical Society of Australia.
Prof Lisa Harvey-Smith, an astrophysicist at UNSW Sydney and not an author of the paper, said there were two major forces moving objects in space: gravity and electromagnetism.
“We’re really familiar with gravity because it pulls us to the Earth. It keeps us on the planet. It makes the Earth go around the Sun, it makes the Moon go around the Earth, and so on,” he said.
Electromagnetic forces were the other important component. Magnetic fields are a naturally occurring phenomenon used for navigation in magnets and old-fashioned compasses, but are also responsible for creating light and color. A magnetic field is a physical property that can be created by the movement of charged particles or molten metals in the Earth’s core.
“The Earth is actually a magnet, it creates its own invisible magnetic field,” he said. “And that tells us which way is north and south, which is really useful.
“If you extend this to space, we learn that other objects are actually magnets, too. Things like stars and galaxies create magnetic fields. And in fact, when you look at the emptyest, widest regions of space, we still see magnetic fields.”
Harvey-Smith said it was “wonderful” that the data was made available as a “true open data repository that anyone can use”.
“The result of creating the map is not the final product; the final product will come over the next few years as scientists research and do their own studies of specific star-forming regions or specific galaxies. And many discoveries will come from that map.”
