Radio signals unlikely to be extragalatic aliens saying ‘hi’
ultra-brief repeating energy bursts from deep space for only the second time in history, with some suggesting they could be evidence of advanced alien life. Two researchers shared their views with China Daily writer Zhang Zhouxiang:
ASTRONOMERS HAVE DETECTED
Shi Hao, a researcher of space technology
Even if there is the possibility an extraterrestrial civilization sent the fast radio bursts (FRB), the distance to us is beyond the reach of any technology we can image.
A little comparison will explain how far away the origin of the signal is from us. The distance from the Earth to the surface of the sun is called an Astronomical Unit (AU), and it takes light from the sun about eight minutes to reach the Earth.
Voyager 1, human kind’s longest travelling device that started in 1977, is now 145 AU from the Earth after 42 years of travelling, yet that’s only 0.23 of one light-year.
It would take more than 17,000 years for Voyager 1 to travel one light-year, and the distance to the origin of the FRB is 1.5 billion times that.
And taking a large perspective, some scientists believe the radius of the universe is 13.7 billion light-years; The FRB signal this time has travelled about one ninth of that to reach us.
Yu Jun, a senior editor on space at pop-science website guokr.com
The signal comes from 1.5 billion light-years away, and the long distance means a high
attenuation rate. In other words, the burst at the origin of the signal must be extremely powerful so that we can receive it. There is no way to calculate the exact amount of energy needed this time, but if we compare it to the sun: It is like bursting out the energy radiated by the sun for dozens to tens of thousands of years within 0.01 second.
Since the discovery of the first FRB in 2007, humans have only observed about 60 of them. As a result of insufficient observation data, there is no confirmed theory on what phenomenon produced them.
However, considering the extremely high amount of energy they need, the number of “suspects” is limited, too. According to existing theories, there are at least several possible causes of FRBs, such as the merging of black holes or neutron stars, hyperflares of magnetars, especially energetic supernova, or the collapse of the magnetospheres of Kerr–Newman black holes.
Strictly speaking, the possibility of a super extraterrestrial civilization sending such a signal cannot be excluded, but the possibility is really low considering the high amount of energy needed. Besides, there is no evidence leading specifically to this possibility. So there is no need to exaggerate it.