Somewhere in our galaxy, a collapsed star spins fast enough to sweep a beam of radiation across the cosmos like the revolving light of a coastal lighthouse. Astronomers call such objects pulsars, and one of them — PSR J1101−6101, embedded in what is known as the Lighthouse Nebula — has just given up one of its deepest secrets.
For the first time, NASA's IXPE (Imaging X-ray Polarimetry Explorer) has directly measured the magnetic fields around this pulsar's nebula. That matters because a pulsar is no ordinary star. When a massive star dies, its core can collapse into a neutron star barely the width of a city but packed with more mass than the Sun, spinning hundreds of times per second and wrapped in magnetic fields billions of times stronger than Earth's. Those fields act like invisible rails that funnel ultra-high-energy particles out into space.
Until now, scientists could only infer a pulsar's magnetic structure from the radio pulses it emits and from computer models. IXPE changed that by measuring the polarization of X-rays — the distinct way the light's waves are oriented as it travels. Polarization is a fingerprint of magnetic fields, so by reading it, the telescope essentially traced the shape of the fields directly rather than guessing at them.
The result confirms long-standing theory about how these extreme objects release their trapped particles, and it gives physicists a rare, clean look at matter and energy behaving under conditions that cannot be reproduced in any laboratory on Earth. Pulsars are natural particle accelerators, and understanding their magnetic architecture helps explain where the galaxy's most energetic cosmic rays come from.
Knowledge takeaway: NASA's IXPE telescope directly mapped the magnetic fields of the "Lighthouse" pulsar PSR J1101−6101 by reading the polarization of its X-rays — the first direct measurement of such fields, turning a decades-old inference into observed fact about the universe's most extreme engines.