This is by no means the first time this phenomenon has occurred. Ground-based radio telescopes have previously collected radio signals from the cosmos, and astrophysicists have managed to explain in a plausible way most of them. In fact, stars, nebulae, galaxies, and even planets are astronomical sources of radio waves that cosmologists are able to identify from Earth from time to time.
Of course, it is not a question of lightly attributing the authorship of these signals to an extraterrestrial civilization. There are many possible completely natural explanations that often fit this puzzle perfectly. The pulsar GPMJ1839-10, for example, emits a periodic radio signal that reaches Earth every 21 minutes. Astrophysicists have been observing it for no less than 35 years, and they know it quite well. There is no mystery here. However, the story we are about to tell you is different. And exciting.
This very strange radio signal oscillates between three different states
The protagonists this time are the MeerKAT radio telescopes, which is installed in South Africa, and ASKAP, which resides in Australia. In fact, it was the latter that first picked up the rare radio signal that is the subject of this article. The astronomers operating it realized that they were receiving a radio signal with an exact periodicity of 53.8 minutes. There is nothing really surprising up to this point because other similar signals arrive at Earth from, among other objects, pulsars or other types of neutron stars.
“The most intriguing thing is that this object exhibits three different emission states, and each of them has completely different properties from the other two”
However, it didn’t take them long to realize that this radio signal is different from the others. And it’s very unusual for a reason: it goes through three completely different states. At some times it emits flashes that last between 10 and 50 s, and on these occasions the radio waves spread in a single direction. On other occasions the pulses are much shorter (lasting about 370 ms) and propagate in all directions. And finally, at some moments the object that causes this signal remains completely “silent”. In absolute silence.
The astrophysicists who are investigating this cosmological phenomenon have published a very interesting article in Nature Astronomy in which they explain everything in great detail. Dr. Manisha Caleb, who is the lead author of this study, confirms that we are facing an unprecedented phenomenon: “The most intriguing thing is that this object exhibits three different emission states, and each of them has completely different properties from the other two. […] “The MeerKAT radio telescope has played a crucial role in distinguishing between these states.”
Be that as it may, the most surprising thing is that the very strange radio signal that is reaching Earth is unlike any other we have received before. Astrophysicists led by Caleb suspect that the object emitting it could be a neutron star or a white dwarf, but there is a problem: the behavior of the signal. can’t be explained for the moment by the physics used by cosmologists to describe these two objects.
In other words: current astrophysics cannot explain this phenomenon. This does not mean at all that I will not do it in the future. With a little luck, astrophysicists will find the key and understand the nature of the signal. In the meantime we have no choice but to remain waiting.
Image | NASA Goddard Space Flight Center
More information | Nature Astronomy
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