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What is the deal with these "mysterious fast radio outbursts from space"?



On January 9, 2019, a Canadian team of astronomers using a radio telescope called CHIME published a study announcing the second recorded instance of a repetitive Fast Radio Burst (FRB). Although (non-repetitive) FRBs have been known to science since 2007, the mechanisms that generate them are largely a mystery. These millisecond electromagnetic radiation pulses, which are inevitably generated by extremely high-energy events, arrive from billions of light-years on Earth, where they are detected by large radio telescope arrays. Until recently, FRBs were exclusively singular, transitory events, making it difficult to study or understand them with any depth or accuracy.

In 201

6, however, the first repeating FRB was confirmed by a group of researchers working with the Very Large Array Telescope in New Mexico. In this case, "FRB 121102" was first re-discovered from the sky in 2012 and 2015. Due to their repetitive nature, the researchers were able to accurately determine the dwarf galaxy from about 2.5 billion light years. The more repetitive FRBs are recognized by scientists, the more likely they are to understand their origins.

The discoveries of CHIME, which included the second repetitive FRB 12, were previously made. Telescope is even fully functional. The authors argued that these findings could open the possibility that repetitive FRBs are common in our universe. In their study, published in the journal Nature the authors concluded that "CHIME / FRB, with its broad field and high sensitivity, was predicted to find a large population of repeaters, if any. That one of our first 13 events is repeated suggests that there is indeed a considerable population.

If you've heard this discovery from any source other than Nature you may have the impression of a leading person hypothesis for the source of these bursts was a kind of alien technology:

  • Mysterious fast bursts of radio from Space "Could Be Aliens" The Guardian )
  • Mysterious repeated radio signals have reached Earth from a galaxy 1.5 billion light-years away (but are they evidence of alien civilizations?) ( Daily Mail ).
  • alien signals? Bizarre "Fast Radio Bursts" discovered from outer space ( USA Today )

Of course, everything could be "alien", but for such an argument this would have been necessary relevant evidence. The CHIME paper did not attempt to provide such an argument, and therefore did not provide any concrete evidence for a foreign technology scenario. Instead, this paper provided evidence that the same narrow area of ​​space more than once emitted enormous amounts of radio energy. Almost all outlets that suggest an algebra mechanism linked to FRBs cited the same speculative testimony of Harvard astronomer Avi Loeb. In 2017 (in a paper that is not related to the study being reported), Loeb suggested that one possible source of FRBs could be an alien civilization that radiates radio waves to transport distant light sails, thin ones Objects that are accelerated by solar radiation pressure. It should be noted that Loeb was also the most important scientific fuel petrol that reports that an object that passed through our solar system at the end of 2018: "Oumuamua" was an extraterrestrial light sail.

Loeb is very interested in light sails. He chairs a consultative committee for a project called Breakthrough Starshot, which aims to send a light sail to the star closest to our own sun. His analyzes do not attempt to represent a foreign mechanism for these various occurrences of FRB, but simply show that such scenarios are possible in our understanding of the physical laws of the universe and could involve a light sail. Although the topic is intriguing, it is (from the point of view of science reports) a distraction from the actual scientific advances of the CHIME team.

CHIME (Canadian Hydrogen-Intensity Mapping Experiment) was originally developed to detect hydrogen radio emissions deep in the original past of our Universe. However, the ability to detect extremely weak radio sources in a huge sky field makes it an ideal tool to monitor even for FRBs. It's not that FRBs are rare: some estimates suggest that every eight seconds an FRB occurs somewhere in the sky. It's like that the universe is pretty big, and you have to constantly watch a huge area of ​​the sky to find an FRB and an even larger amount to find an instance of a repetitive one.

Conquering Heaven With the high-sensitivity radio telescope CHIME, experts predicted that a much larger number of FRBs would be detected and even FRBs repeated. Based on the first results in Nature their assumption seems to have been confirmed. Over a period of three weeks in August 2018, the CHIME telescope detected 13 FRBs, one of which was a repeater. In an interview with The Guardian the astrophysicist of CHIME and Professor Ingrid Stairs of the University of British Columbia said: "So far, there was only one known FRB. Knowing that there is another indicates that there could be more out there. And with more repeaters and more sources available for learning, we can understand these cosmic puzzles – where they come from and what causes them. "

West Virginia University astrophysicist Sarah Burke-Spolaor was one of the team that identified the site of the first repetitive FRB known to science, a faint dwarf galaxy located about 2.5 billion light-years away. This knowledge enabled the team to feel the energy behind the event that produced the radio waves, as described in Science News in January 2017: "For about five milliseconds, the eruption has all the stars in it Overshadowed galaxy and rival the luminosity of burning gas disks whirling around supermassive black holes, said Burke-Spolaor, one of the researchers involved in the project. "

In a telephone conversation with us, Burke-Spolaor, who did not participate in the CHIME study, said that "the two leading hypotheses [for what causes FRBs] are more or less a sort of black hole at the moment, or some kind of neutron star origin. "Neutron stars are the collapsed cores of once giant stars that can emit electromagnetic radiation. "It would be [have to] a very extreme neutron star … much more energetic than what we see in our galaxy" as radio waves spread for billions of light-years, said Burke-Spolaor.

Some scientists, including members of the CHIME team, present scenarios involving a combination of neutron stars and supermassive black holes. This existence of a black hole is supported by the observation that the radio impulses that make up most of the recently discovered FRBs are "scattered" in a way that simulates a high energy or "special" environment. Speaking to The Guardian CHIME team member Cherry Ng said, "This could mean a kind of dense lump like a supernova remnant or near the central black hole in a galaxy. But it must be in a special place to give us all the diversion we see. "

Aside from being a scientific puzzle that may one day be resolved, as more recurrent FRBs are discovered by large-scale telescopes such as CHIME, these FRBs could also be a tool to better understand the vast void of our universe to understand. In a commentary dated November 18, 2018, in Nature Astronomy Burke-Spolaor argued that the FRBs provided science with a "rich set of data that allowed both the mechanisms that generate the bursts and the artifacts "Gravitational waves, neutrinos, and the entire electromagnetic spectrum are now open to business," she wrote.

"Until recently, there were more theories [about FRBs] than actual radio bursts," joked Burke-Spolaor With these early results of CHIME, this balance can shift.


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