Scientists seek origin of mysterious deep-space radio signal flashing for an hour

Scientists in Australia have identified a peculiar radio signal emanating from space, characterized by its unusually long flashes that last for nearly an hour—the longest duration observed to date. This signal, which exhibits a combination of extended bright flashes interspersed with short, weak pulses, and intermittent silence, remains an enigma as researchers have yet to determine its origin.

Typically, astronomers frequently detect radio signals from across the universe, known as radio transients, which vary in duration and pattern. These signals often originate from rotating neutron stars called pulsars, which emit regular bursts of radio waves similar to cosmic lighthouses. Pulsars generally rotate at high speeds, completing a rotation in mere seconds or even less. However, the recently discovered radio signal, named ASKAP J1935+2148, stands out due to its hour-long cycle, making it a unique and rare occurrence.

The research team, working at the Wajarri Yamaji Country in Western Australia, utilized the CSIRO’s ASKAP radio telescope to detect this signal. ASKAP J1935+2148 was noted for its “circularly polarised” radio waves, which twist as they travel through space. This discovery places it in a relatively new category of long-period radio transients, with only two other similar signals known, and none with such a prolonged cycle.

Despite extensive observations, the source of ASKAP J1935+2148 remains a mystery. One hypothesis is that it could be a slow-spinning neutron star. Alternatively, it might be a white dwarf—a burnt-out star remnant about the size of Earth. While white dwarfs often rotate slowly, no known mechanism explains the intensity of this radio signal. Another possibility is that the object could be part of a binary system, where a neutron star or white dwarf orbits another star.

The research team emphasizes that further studies are necessary to confirm the exact nature of the object. Regardless of the outcome, understanding this phenomenon could significantly advance our knowledge of these extreme cosmic entities.

The findings were published in the journal Nature Astronomy.