Jun 28, 2020 12:52 AM
https://www.theatlantic.com/science/arch...rn/613369/
EXCERPTS (Marina Koren): For about four days, the radio waves would arrive at random. Then, for the next 12, nothing. Then, another four days of haphazard pulses. Followed by another 12 days of silence. The pattern—the well-defined swings from frenzy to stillness and back again -- persisted like clockwork for more than a year.
Dongzi Li, a doctoral student at the University of Toronto, started tracking these signals in 2019. She works on a Canadian-led project, CHIME, that studies astrophysical phenomena called “fast radio bursts.” These invisible flashes, known as FRBs for short, reach Earth from all directions in space. They show up without warning and flash for a few milliseconds, matching the radiance of entire galaxies.
Astronomers don’t know what makes them, only that they can travel for millions, even billions, of years from their sources before reaching us. In the past decade, astronomers managed to detect about 100 of them before they vanished. [...] The first FRB was discovered in 2007...
[...] Astronomers have now come up with a few potential explanations for the source of the FRB that jams to its own distinct tune. Maybe the object is spinning and wobbling in such a way that its light points toward Earth only every four out of 16 days, which, from our perspective, would look like periodic bursts. Maybe it’s actually two objects—a neutron star orbiting another neutron star or even a black hole—locked in an orbit that squishes one star so much that it flares as it swings around. Maybe the source resides near a cloud of interstellar gas that amplifies its radio emissions, like a cosmic magnifying glass, as it passes through.
With so many scenarios on the table, I couldn’t resist asking astronomers about the option at the very edge of possibility, unlikely but also impossible to rule out: aliens. [...] No, because the story with FRBs -- the story with most mystifying astrophysical phenomena -- is that it’s never aliens. Although, people more qualified than I am are also considering that, okay, maybe, these might, on the off chance, be alien signals ... But although the newly found FRB is indeed weird, it’s probably not a beacon from an advanced civilization. “This shares a lot of properties with other sorts of FRBs, which are not regular at all, so we don’t have any reason to believe that this one in particular is special,” Vikram Ravi ... told me ... “The signals are quite broadband, whereas it’s much more efficient to communicate in narrowband,” he said. “One would hope that if someone was communicating, it would be a bit more well defined.”
FRBs are beacons of another kind, and astronomers have detected more than is widely known. In January, members of CHIME wrote in a paper posted on the preprint repository arXiv.org that they have detected 700 FRBs in less than a year. [...] As these radio waves propagate through space, they pass through all kinds of matter, from the most luminous galaxies to nearly invisible wisps of cosmic dust, slowing down here and there. These encounters are encoded in the radio waves, and scientists can pick them out when the signals reach us. Astronomers are particularly interested in studying the wispy material that lies between galaxies, because “we have no information other than what FRBs are beginning to give us,” says Shami Chatterjee ... To see inside this expanse, astronomers need the help of these strange signals that they still barely understand... (MORE - details)
EXCERPTS (Marina Koren): For about four days, the radio waves would arrive at random. Then, for the next 12, nothing. Then, another four days of haphazard pulses. Followed by another 12 days of silence. The pattern—the well-defined swings from frenzy to stillness and back again -- persisted like clockwork for more than a year.
Dongzi Li, a doctoral student at the University of Toronto, started tracking these signals in 2019. She works on a Canadian-led project, CHIME, that studies astrophysical phenomena called “fast radio bursts.” These invisible flashes, known as FRBs for short, reach Earth from all directions in space. They show up without warning and flash for a few milliseconds, matching the radiance of entire galaxies.
Astronomers don’t know what makes them, only that they can travel for millions, even billions, of years from their sources before reaching us. In the past decade, astronomers managed to detect about 100 of them before they vanished. [...] The first FRB was discovered in 2007...
[...] Astronomers have now come up with a few potential explanations for the source of the FRB that jams to its own distinct tune. Maybe the object is spinning and wobbling in such a way that its light points toward Earth only every four out of 16 days, which, from our perspective, would look like periodic bursts. Maybe it’s actually two objects—a neutron star orbiting another neutron star or even a black hole—locked in an orbit that squishes one star so much that it flares as it swings around. Maybe the source resides near a cloud of interstellar gas that amplifies its radio emissions, like a cosmic magnifying glass, as it passes through.
With so many scenarios on the table, I couldn’t resist asking astronomers about the option at the very edge of possibility, unlikely but also impossible to rule out: aliens. [...] No, because the story with FRBs -- the story with most mystifying astrophysical phenomena -- is that it’s never aliens. Although, people more qualified than I am are also considering that, okay, maybe, these might, on the off chance, be alien signals ... But although the newly found FRB is indeed weird, it’s probably not a beacon from an advanced civilization. “This shares a lot of properties with other sorts of FRBs, which are not regular at all, so we don’t have any reason to believe that this one in particular is special,” Vikram Ravi ... told me ... “The signals are quite broadband, whereas it’s much more efficient to communicate in narrowband,” he said. “One would hope that if someone was communicating, it would be a bit more well defined.”
FRBs are beacons of another kind, and astronomers have detected more than is widely known. In January, members of CHIME wrote in a paper posted on the preprint repository arXiv.org that they have detected 700 FRBs in less than a year. [...] As these radio waves propagate through space, they pass through all kinds of matter, from the most luminous galaxies to nearly invisible wisps of cosmic dust, slowing down here and there. These encounters are encoded in the radio waves, and scientists can pick them out when the signals reach us. Astronomers are particularly interested in studying the wispy material that lies between galaxies, because “we have no information other than what FRBs are beginning to give us,” says Shami Chatterjee ... To see inside this expanse, astronomers need the help of these strange signals that they still barely understand... (MORE - details)
