Scientists map universe’s invisible force to show sky as you’ve never seen it

Scientists have released the largest and most detailed maps ever made of the universe’s magnetic fields, using data from Australia’s strongest radio telescope to visualise the hidden force that may help govern the structure of the entire cosmos.

The project casts crucial light on a final bastion of cosmic mystery: how these giant magnetic structures influence the formation of galaxies, the birth of stars, the roaring of radioactive “space weather” and the lifespan of our home galaxy.

The map is five times larger than all previous efforts to visualise the universe’s magnetism combined, said lead author Dr Alec Thomson, a CSIRO scientist who works at the SKA Observatory in Western Australia.

“That gives us the best view we’ve ever had on magnetic fields throughout the universe,” Thomson said.

“We can see further than we’ve ever been able to see before, and we can see the Milky Way in 10 times better detail.”

Intergalactic magnetism could be as crucial to the architecture of space as gravity, influencing the flow of material through space and shaping the evolution of the universe as we know it.

Magnetic fields are generated when electrical charges move – such as electrons flowing through a wire.

The electrically conductive molten metal in Earth’s core, for example, generates a vast magnetic field which shields the planet from space radiation and solar flares.

Without it, our atmosphere would be stripped away by cosmic wind and our planet would be as barren as Mars.

Over the past few decades, we’ve begun to understand magnetic fields are also generated by the spinning of the galaxies and the blasts of supernovae.

That contributes to a complicated web of magnetism that wends throughout the entire universe.

About 99.9 per cent of visible material in the universe by volume is plasma, or charged gas, which can be channelled and manipulated by magnetism.

“That’s why magnetic fields have such a strong influence on how that material moves around the universe and inside galaxies,” Thomson said.

Large-scale simulations of the universe show galaxies are not flung randomly across space, but gather in clumps linked by filaments, resulting in images which look like neurons in the brain or tangly redback spider webs.

Gravity plays a major role in this structure, but magnetism could be another key architect.

Magnetic fields also slow down the formation of new stars by a factor of three, acting as a foil to gravity as it clumps together gas and dust. The fields also underpin how gusts of electromagnetic interstellar winds blast from stars and into space.

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