Astronomers have discovered three sudden changes in the rotation speed of a pulsar known as PSR J1637−4642, a young neutron star that had remained unusually calm for many years. The findings, based on over 15 years of data collected using the Parkes radio telescope, were published on the arXiv preprint server on August 20 and are set to appear in the Astrophysical Journal Letters. These observations provide new insights into the internal dynamics of neutron stars, which are the dense remnants of massive stars that have exploded as supernovae. PSR J1637−4642 is a relatively young pulsar, estimated to be about 41,000 years old, and it spins extremely rapidly—once every 154 milliseconds. Despite its youth and high energy output, it had not shown any signs of "glitches" during the decade of observations following its discovery. Glitches are sudden, small increases in the rotation speed of a pulsar, often attributed to internal changes within the neutron star. A team of astronomers led by Zhaoyi Wang of Xiamen University analyzed data collected from 2009 to 2024 using the Murriyang radio telescope. Their analysis revealed three distinct glitches. The first occurred around 2018 and was the largest, increasing the pulsar’s rotation frequency by about 17.54 microhertz—equivalent to a fractional change of about 2.7 parts per million. A second, smaller glitch occurred three years later, changing the frequency by about 14 nanohertz. A third glitch, even smaller, occurred roughly 2.7 years after the second, increasing the frequency by about 179 nanohertz. Following the first glitch, the pulsar did not immediately stabilize at its new rotation rate. Instead, the change gradually eased over time. By modeling this process, researchers estimated that about 1.9% of the neutron star’s moment of inertia—essentially its resistance to changes in rotation—is due to superfluid material in its inner crust. This superfluid material is thought to be composed of neutrons that flow without friction, allowing them to transfer angular momentum to the solid crust in sudden bursts, causing the observed glitches. The study suggests that the long period of inactivity before the first glitch may have allowed stress to build up within the star, eventually leading to the sudden spin-up event.