Satellite inactive for 60 years emits mysterious radio signal
Astrônomos Australians detected in June 2024 an extraordinarily powerful radio signal emanating from space. The object producing the signal shone brighter than any other celestial body visible at the time, leaving researchers perplexed. Further investigation revealed an unexpected origin: a communications satellite launched by NASA in 1964, which had been inactive for almost 60 years, was now transmitting again.
The discovery raised questions about the nature of the signal and reignited concerns about the growing amount of debris in Earth orbit. The article analyzing the results was published on Astrophysical Journal Letters on June 30 last year.
Detecção of signal by Australian radio telescope
Professor Associado Clancy James and his colleagues from Instituto to Radioastronomia to Universidade Curtin at Austrália Ocidental identified the phenomenon using the ASKAP radio telescope. Esse equipment consists of 36 satellite dishes, each with a height equivalent to a three-story building. Researchers typically use the data collected to look for fast radio bursts, which are flashes of energy emitted by distant galaxies.
James described the discovered radio waves as an extraordinarily powerful burst lasting about a millisecond. The complete signal lasted approximately 30 nanoseconds, while the main part lasted only 3 nanoseconds, reaching the technical limit of available observation instruments. The signal strength was between 2,000 and 3,000 times brighter than all other radio data detected by the instruments. Era the brightest object in the sky at that brief instant.
Inicialmente, researchers believed they were observing a new type of celestial phenomenon. Astronomers suspected that such explosions could originate from magnetars, which are extremely dense remnants of dead stars with powerful magnetic fields. Segundo James, magnetars are completely unusual and represent the most extreme phenomenon in the universe before something becomes a black hole.
Origem identified on Relay 2 satellite
The signal, however, emanated from a location very close to Terra, incompatible with originating from a distant celestial body. The researchers located the source approximately 4,500 kilometers away, a depth coinciding almost perfectly with the orbit of an early satellite called Relay 2.
NASA had launched Relay 2 in 1964 as an experimental communications satellite. Era was an improved version of Relay 1, placed into orbit two years earlier, and was used to relay signals between Estados Unidos and Europa. The satellite also transmitted signals from Jogos Olímpicos and Tóquio carried out that same year. The mission ended three years later when failures in its main equipment turned it into space debris.
Após decades of complete silence, the inactive device began transmitting again, surprising the scientific community. James and his colleagues began to suspect a connection between this abandoned satellite and the strange signal detected in 2024.
Leia Também
First World Cup knockout stage today: where to watch, time and lineups
Microsoft algorithm cuts Xbox Series X price in half directly at the console store
Apple surprises the market by launching an ultra-thin 5.5 mm smartphone with a liquid glass screen
Investigação on the origin of the mysterious signal
The researchers realized that the source of the signal was located very close to the receiving antenna, tens of thousands of kilometers away, because the image captured by the telescope had an initial blur. Conforme James explained, the signal seemed quite weak when first detected. As the researchers zoomed in on the data, the brightness increased significantly, revealing a complex temporal structure.
Astronomers have come up with two main theories about what caused such a powerful flash:
- Liberação sudden static electricity accumulated on the metallic surface of the satellite
- Impacto of micrometeorites less than 1 millimeter in size, which when colliding with spacecraft traveling at speeds of 20 kilometers per second or more, could transform fragments into plasma, a very hot and dense gas capable of emitting very short-lived radio bursts
The most likely explanation, according to James, is the discharge of stored static electricity. Interactions with micrometeorites require extremely specific conditions to occur, making this cause less likely according to available research analyses.
Implicações for space debris monitoring
The identification of the signal as originating from Relay 2 highlighted growing concerns about orbital debris. Non-functional Satélites continue to circulate Terra for years, decades, or centuries, depending on their altitude and composition. Esses inactive objects pose potential risks to active and future space operations.
The case of Relay 2 demonstrates that apparently dead equipment can emit unexpected signals, creating additional challenges for astronomers and space engineers. The research of James and his team contributes to a better understanding of the behaviors of ancient space debris and improves detection capabilities for rare celestial phenomena.
