**Mysterious Interstellar Radio Signals: Blinking on and off Every 18 Minutes**
**Introduction**
Last year, astronomers made a fascinating discovery—a radio signal in space that switched on and off every 18 minutes. This discovery raised many questions and sparked the curiosity of researchers. While astronomers are accustomed to observing repeating radio signals in space, they typically blink at a much faster rate. These signals are often emitted by pulsars, which are rotating neutron stars that emit energetic beams resembling lighthouses. As these pulsars rotate towards and away from Earth, they appear to blink on and off.
However, the radio signal observed last year had a much slower pace and its source remained a mystery. Further analysis revealed that the signal might be a result of a magnetar—a pulsar with powerful magnetic fields. Magnetars have the potential to generate radio waves for several months before ceasing their production.
Unfortunately, since the data used to detect the source was gathered in 2018, by the time astronomers further examined it in 2020, the radio waves were no longer being emitted. This lack of additional data made it impossible to test the magnetar theory.
**Searching for Similar Phenomena**
Despite the setback in analyzing the magnetar theory, astronomers remained determined to find other similar radio sources. History has shown that every phenomenon discovered in our vast universe is not unique. With this in mind, researchers set out to use the Murchison Widefield Array radio telescope in Western Australia to scan the Milky Way galaxy every three nights for several months.
Their efforts were rewarded when they found a brand-new source in a different region of the sky. This source emitted repeating signals every 22 minutes. Excited about this discovery, astronomers utilized multiple telescopes in various spectrums, including radio, X-ray, and optical light, to make extensive observations. The signals lasted for five minutes each, with gaps of 17 minutes in between. The object they observed resembled a pulsar, but it spun 1,000 times slower.
**Surprising Discoveries**
The biggest surprise came when scientists delved into the archives of the Very Large Array in New Mexico, which holds the longest-running collection of radio observation data. In their search, they found pulses from the newly discovered source in data dating back to 1988.
The ability to observe the pulses over a span of three decades allowed astronomers to accurately time the signals. Strangely, these signals did not align with their current understanding of pulsars slowing down over time. The observations indicated that the source was not losing momentum as expected.
The findings, as detailed in an article published in Nature, revealed that the source lies “below the death line.” This line represents the theoretical limit of how neutron stars generate radio waves. Even with complex magnetic field models, the source remains below this threshold. Additionally, if the source were a magnetar, the emission of radio waves should only be visible for a few months to years, not the 33 years and counting that have been observed.
**The Temptation of Extraterrestrial Intelligence**
Given the enigmatic nature of these repeating radio signals, it is tempting to consider the possibility of extraterrestrial intelligence. This is reminiscent of the early days of pulsar discovery, when astrophysicist Jocelyn Bell Burnell and her colleagues humorously nicknamed their find “Little Green Men 1.”
However, as further detections were made, it became increasingly clear that aliens were not the source. The likelihood of numerous similar signals coming from various parts of the sky is exceedingly low. Additionally, the pulses observed in these radio signals contain no discernible information, resembling natural radio sources’ noise across all frequencies. The energy required to emit signals at such frequencies is immense, comparable to that of a neutron star.
While the extraterrestrial intelligence hypothesis may be intriguing, it does not encourage scientific exploration or the testing of new ideas. An approach like this can be labeled the “aliens of the gaps,” which stunts progress and limits comprehensive analyses of phenomena.
**Continued Observations and Solving the Mystery**
The source of these mysterious repeating radio signals remains active, presenting a unique opportunity for researchers worldwide to observe it. Through creative follow-up observations and in-depth analyses, scientists anticipate uncovering the secrets behind this cosmic mystery.
In conclusion, the discovery of these repeating radio signals with unusual characteristics has ignited the scientific community’s curiosity. Despite the challenges in understanding their origin, astronomers are determined to unravel the mysteries of the universe by using innovative research methods and collaborative efforts. Our quest for knowledge knows no bounds, and with each discovery, new questions arise, allowing us to delve deeper into the enigmatic cosmos.
**Image Credit: The International Centre for Radio Astronomy Research**
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