Magnetic fields are invisible, but researchers have just built the most detailed photo yet showing nearly four million galaxies

The CSIRO ASKAP radio telescope has built the largest mag of the universe's magnetic fields yet.

I’ve long been awed by photographs of the night sky, but one of the latest images to stop me in my tracks isn’t a “photograph” at all. A radio telescope in Australia has built the largest magnetic map of the universe yet, a colorful image five times larger than all the previous radio mapping efforts combined.

The data comes from Australia’s national space agency CSIRO and the SKA Observatory, which recently used the ASKAP radio telescope to scan the skies and build the largest radio map of the universe yet.