Physicists have clarified the mysterious signal detected on Earth, originating from 6,200 light-years away (video).

Inside the remnant of the supernova known as the Crab Nebula lies the pulsar PSR B0531+21 (also referred to as the Crab Nebula pulsar). It emits peculiar radio pulses toward Earth, containing a signal that has puzzled scientists for many years. This signal has been dubbed the zebra pattern due to the unusual arrangement of wavelength bands in graphical displays, resembling zebra stripes. No other object in space produces such radio emissions. However, astrophysicists have now unraveled the mystery behind this signal. The study has been published in the journal Physical Review Letters, reports ScienceAlert.

The pulsar in the Crab Nebula is a neutron star formed from the explosion of the supernova SN 1054 nearly 1,000 years ago. A supernova is the explosion of a massive star that has reached the end of its life. After such an explosion, a remnant often remains, composed of the gas from the deceased star, which in this case is the Crab Nebula. It is located about 6,200 light-years away from us.

Neutron stars are extremely dense spheres with a diameter of approximately 20 km, containing more than twice the mass of the Sun. Pulsars are a type of neutron star that spins very rapidly. They emit jets of radio waves from their poles. The rotation period of the pulsar in the Crab Nebula is about 33 milliseconds, meaning it emits radio waves approximately once every 30 seconds.

Although this pulsar was discovered back in the 1960s, the mysterious zebra pattern in its radio pulses was only identified in 2007 and has remained an enigma for scientists ever since.

According to the authors of the study, the pulsar PSR B0531+21 is the only known object in the universe that creates a zebra pattern, which appears only in a single radio pulse with a frequency ranging from 5 to 30 Hz.

Astrophysicists proposed that the zebra pattern represents a diffraction fringe and developed a model based on wave optics to calculate the plasma density of the pulsar. This led to an explanation for the strange radio signal.

Researchers found that when the pulsar emits radio waves, the interaction between the plasma and the pulsar's magnetic field creates a diffraction interference pattern that resembles zigzagging zebra stripes.

The magnetic field of the pulsar generates charged particles that form a dense plasma, which varies with distance from the star. As the radio wave travels through the plasma, it passes through sparse areas but is reflected by the dense plasma. This reflection changes depending on the frequency. Low frequencies are reflected from greater distances and cast larger shadows, while high frequencies create smaller shadows, resulting in different spacing between the stripes.

Astrophysicists state that the zebra pattern represents an interference pattern created by the diffraction of light at various plasma densities within the pulsar's magnetic field.