Scientists have produced the largest and most detailed map ever made of the universe’s magnetic field, using data from Australia’s most powerful radio telescope to reveal a hidden force that could help govern the structure of the universe.
The project sheds important light on the last bastion of the universe’s mystery: how these massive magnetic structures influence galaxy formation, star birth, the rumbling of “space weather” and the lifespan of our home galaxy.
The map is five times larger than all previous efforts to visualize the universe’s magnetosphere combined, said lead author Dr Alec Thomson, a CSIRO scientist working at the SKA Observatory in Western Australia.
“That gives us the best view we’ve ever had of the magnetic field in the universe,” Thomson said.
“We can see more than we’ve ever seen before, and we can see the Milky Way in 10 times detail.”
Galactic magnetism may be as important to the architecture of space as gravity, affecting the flow of material through space and shaping the evolution of the universe as we know it.
Magnetic fields are produced when electric charges are moved – such as electrons flowing through a wire.
Molten conductive metal in the Earth’s core, for example, creates a strong magnetic field that protects the planet from cosmic radiation and solar radiation.
Without it, our atmosphere would be stripped away by the cosmic wind and our planet would be as barren as Mars.
In the last few decades, we have begun to understand that magnetic fields are also produced by the spinning of galaxies and supernovae explosions.
This contributes to the complex magnetic network that runs throughout the universe.
About 99.9 percent of the visible matter in the universe by volume is plasma, or charged gas, which can be transmitted and manipulated by magnets.
“That’s why magnetic fields have such a strong influence on how the material moves around the universe and within the galaxy,” Thomson said.
Large-scale simulations of the universe show that galaxies are not thrown randomly through space, but cluster together in bundles connected by filaments, resulting in images that resemble neurons in the brain or the web of a red-backed spider.
Gravity plays a major role in this design, but magnetism can be another important architect.
Magnetic fields also slow star formation to a third degree, acting as a gravitational foil as gas and dust coalesce. Those fields also support how the interstellar electromagnetic wind blows away from the star and into space.
Thomson and his co-authors have made the map data public so that others can use it to learn more about these events.
The new maps were created using data from CSIRO’s ASKAP radio telescope, 750 kilometers north-east of Perth.
Light moving toward Earth from distant galaxies is bent as it passes through magnetic fields.
The scientists processed the data captured by the telescope to determine how the light waves were bent on their way to Earth. Working backwards, researchers can find and map the magnetic field.
Scientific images provided by the project team show the magnetic fields as they would appear from Earth.
“Red is where the magnetic fields are pointing towards us and blue is where the magnetic fields are pointing away from us,” Thomson said.
The maps also show magnetic fields thrown by nearby galaxies, called the Magellanic Clouds. Professor Naomi McClure-Griffiths, SKA Observatory’s principal scientist and co-author of the new study, is investigating how magnetism affects the interactions of these neighboring galaxies with the Milky Way.
The astronomer is also interested in investigating how magnetic fields affect “galaxy feeding”, the process by which galaxies extract gas from smaller galaxies to use as raw materials to form new stars.
The magnetic fields of the Milky Way and the galaxy it wants to “eat” can repel each other, slowing down this feeding process that helps keep the galaxy going.
“If that process is slowed down by magnetic fields, then it has implications for the life of our own galaxy,” McClure-Griffiths said.
The researchers hope their mapping data will accelerate fundamental discoveries about the formation and architecture of the universe — and how space became a magnetized world in the first place.
The original data is called Rapid ASKAP Continuum Surveys (RACS). Add a new part of the project – Spectra and Polarization In Cutouts of Extragalactic Sources – and you get SPICE-RACS, a name that evokes something ordinary but represents some of the largest and most mysterious structures in existence.
Thomson said the map is “just the beginning” and more progress will follow in the coming years.
Investigative Journal explains and analyzes science based on evidence. Sign up to get it every week.
Angus Dalton is a science reporter for The Sydney Morning Herald.Connect through X or email address.
