A new radioactive signal from deep space is challenging our understanding of mysterious phenomena, not only because it’s a rare occurrence, but also because it’s not that fast: flashes of radiation thrown through intergalactic space take three seconds, about 1,000 longer than the average.
However, bursts of high-intensity radiation occur every 0.2 seconds during this three-second span of time—something unprecedented in a fast radiation flux.
How did you discover this fast radioactive signal
The signal was spotted by the CHIME detector in December 2019, and scientists knew right away that they had discovered something very strange. “It was extraordinary,” said astrophysicist Danielle Micheli of the Mate Cavli Institute for Astrophysics and Space Research.
“Not that it took a very long time, lasting about three seconds, but that there were remarkably precise regular peaks, emitting every millisecond like heartbeats. This is the first time the signal itself has been uniform.”
Radiation bursts the most amazing cosmic mysteries
One of the most fascinating cosmic mysteries today is FRBs, extremely powerful bursts of radiation at radioactive wavelengths that stretch between galaxies in a very short period of time – usually milliseconds. Within that short time, the burst emits as much energy as 500 million suns.
Most fast bursts of radiation only flow once, and no one has heard of them since. It is impossible to predict. In order to detect one, we only have to hope that it happens when we have a telescope pointing in the right direction that detects these radiations (although projects like CHIME, which has a large field of view, are very helpful in this regard). These are the most common types of radioactive signals.
Receiving repeated signals from a single point in the sky is even rarer. They are fast, frequent bursts of radiation. Because of their frequency, scientists can point a telescope at the sky and study the signals in greater detail. But it is not clear if the same mechanism is responsible for all the rapid radiation bursts.
The difference between rapid radiation bursts
They may vary in intensity, wavelength, polarization and scattering. And one of the fast bursts holds an important clue. In 2020, a fast burst of radiation coming from inside the Milky Way was detected for the first time. Scientists traced it toward a type of neutron star called a magnetar, suggesting that these highly magnetized, high-intensity objects may be responsible for at least some of the fast radiation bursts.
“So far, CHIME has observed many fast bursts of radiation with different characteristics, and we have seen some of them inside highly turbulent clouds, while others seem to lie in clear environments,” Micheli said. “Based on the characteristics of this new signal, we can say that there is a cloud of plasma around the source, It must be very turbulent.”
Types of neutron stars
As for what they are, the signs still point to a neutron star of some kind (unfortunately, there are no signs yet of extraterrestrials).
Neutron stars are the collapsed cores of massive stars that have ended their lives and ejected most of their material into space. When it lacks external pressure support for fusion, the core collapses into an enormously dense body, about 20 kilometers wide, but 2.3 times the mass of the Sun.
A magnetar is a type of neutron star with a very strong magnetic field. Because of the external drag forces of this magnetic field competing with internal gravity, magnetism periodically causes large earthquakes.
Pulsars are neutron stars that emit beams of radiation from their poles, spinning at millisecond scales, so that the beam appears to be pulsing. Micheli and colleagues analyzed the bursts of these radioactive signals and found features in common with the bursts from magnetars and pulsars.
Hopes for locating the source of the regular radioactive signals
Only one problem appeared to them: although the distance traveled by the signal was not clear, it probably came from another galaxy, and its explosion appears to be a million times brighter than the magnetars and pulsars in our galaxy.
“There are not many things in the universe that emit regular and precise signals. Examples we know of in our galaxy are radioactive and magnetic pulsars, which rotate and produce a lighthouse-like emission. We think that this new signal may be a magnetar or an active pulsar,” explained Micheli.
The team hopes to discover more bursts of the mysterious source of this signal, narrowing their search to where it came from and what caused it. In turn, this may help us better understand neutron stars.
“This discovery raises the question of what could be causing this extreme signal that we’ve never seen before, and how we can use this signal to study the universe,” said Micheli. More of them.”
sciencealert