For the past decade, Earth has been the recipient of unusual radio signals originating from deep within space. Initially thought to be the work of extraterrestrial intelligence sending signals across the cosmos, these enigmatic transmissions baffled scientists and sparked widespread speculation. However, a groundbreaking revelation has now uncovered the true source of these mysterious radio waves – and it’s not aliens but a rare and unusual binary star system located over 1,600 light-years from Earth.

The discovery centres around a unique pair of stars in the Saptarishi constellation, also known as Ursa Major. This binary system consists of a red dwarf star and a white dwarf star in orbit around each other. Scientists confirmed that these stars, whose magnetic fields interact with one another, are responsible for generating the strange radio signals detected by researchers. The signals are emitted so regularly that they resemble a cosmic clock, with a pulse reaching Earth every 125 minutes, or roughly every two hours.

Dr Iris de Ruiter, a prominent researcher now at the University of Sydney, uncovered this startling finding in 2024 while analysing data from the Low Frequency Array (LOFAR) radio telescope in the Netherlands. During her research, Dr de Ruiter stumbled upon a signal from 2015, hidden within the data, and discovered several additional signals emanating from the same region. These signals were not fleeting bursts like fast radio bursts (FRBs), which typically last only milliseconds. Instead, the signals persisted for several seconds, with a lower intensity and energy level than FRBs.

The signals’ predictable nature intrigued scientists, prompting them to study the system more closely. Using a large optical telescope, researchers observed the stars in the binary system and identified the faint white dwarf star, which had previously been invisible through standard telescopes. White dwarfs, the remnants of stars that have exhausted their nuclear fuel, are known for their dimness and inability to shine as brightly as living stars. Only their ultra-dense, hot cores remain.

In this binary system, the red dwarf and white dwarf stars revolve around each other, and the interaction of their powerful magnetic fields creates the long-duration radio signals. These waves travel across space for 1,600 years before reaching Earth’s radio telescopes.

The findings from this study provide new insights into how magnetic fields between two stars can generate periodic radio signals. This discovery not only sheds light on the source of these mysterious transmissions but also opens the door for further exploration into other potential binary systems that might be sending similar signals. As scientists continue to explore these cosmic phenomena, this breakthrough offers an exciting opportunity to deepen our understanding of radio waves in space and the various energy sources at play within our galaxy.