A Mysterious Space Signal Has Puzzled Scientists for Over Three Decades

For more than three decades, an enigmatic radio transmission originating from deep space has been consistently reaching Earth every 22 minutes, a rhythmic pattern that has intrigued astronomers. This signal, identified as GPM J1839–10, was uncovered through recent analysis supported by archival data, challenging existing theories of cosmic phenomena. The findings were published in the journal Nature.

An overlooked cosmic signal since 1988

The discovery of GPM J1839–10 emerged during a survey investigating transient cosmic activities such as supernova explosions, stellar flares, and rapidly moving asteroids. Initially detected as a transient event appearing twice on the same night, further investigation revealed that it did not behave like typical short-lived signals.

Unlike typical transient phenomena, this source produces low-intensity, prolonged radio bursts lasting between 30 and 300 seconds. These radio signals often consist of several sub-bursts, adding layers of complexity.

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Reexamination of historical observations showed that this distinct pattern has been recorded as far back as 1988, indicating that GPM J1839–10 has been persistently active and largely unnoticed for decades.

Anomalous pulsar-like behavior

At first glance, the likely explanation was that the source is a pulsar—a compact, spinning neutron star emitting beams of radiation that sweep across space periodically, appearing as pulses when intersecting with Earth. However, pulsars typically emit signals at intervals ranging from milliseconds to a few seconds, not on the order of tens of minutes.

Moreover, a pulsar’s radio emissions depend heavily on its magnetic field, which is sustained by rapid rotation. As the neutron star slows, this radio emission weakens.

Given that GPM J1839–10 rotates approximately once every 1,320 seconds, conventional models suggest it should not produce strong radio waves. Its steady, long-interval pulses present a challenge to our understanding of pulsar mechanics.

Magnetar or white dwarf possibilities

The signal has also been compared to emissions from magnetars, neutron stars with exceptionally powerful magnetic fields. Magnetars are known for sudden, intense bursts of energy, but these typically include high-energy X-rays or gamma rays, which GPM J1839–10 lacks.

Additionally, magnetars generally spin faster than the slow periodicity seen here. An alternative suggestion points to a white dwarf—a dense stellar remnant capable of slower rotation and magnetic activity over longer periods.

While white dwarfs are plentiful within the Milky Way and some have significant magnetic fields, none have been observed to display behavior akin to GPM J1839–10, rendering this hypothesis interesting but unproven.

Introducing a potential new type of astronomical object

The steady 22-minute cycle does not conform to any known category of celestial object. Researchers are considering the intriguing possibility that GPM J1839–10 represents a new class of space phenomena that has evaded detection due to observational constraints or because it operates on timescales and mechanisms not previously explored.

Investigating this enigma further is challenging, as confirming multiple bursts requires dedicating extended telescope time—resources that are often scarce—on specialized radio observatories. Nevertheless, such focused observations could be key to unraveling the nature of this puzzling cosmic signal.