Among the multitude of signals filling space, it is quite difficult to find artificial ones. One of its characteristics is considered to be the narrowness of the transmission band. However, scientists have now established that stars themselves can distort transmissions coming from planets around them.
Signals from aliens
For many years, scientists have been searching for signals from aliens. They believed that they would be able to find them, even if they did not know what they looked like and did not understand the message itself. However, a recent article in The Astrophysical Journal by researchers from the SETI Institute cast doubt on one of the key assumptions that scientists had been relying on.
In fact, signals from aliens do not have to be sought in silence. The universe is full of high-energy processes that constantly generate strong energy flows at different frequencies. And most of them are much stronger than anything that could be generated by a civilization similar to Earth’s.
However, artificial radiation has one peculiarity – it is focused in a single narrow band, in which it is extremely powerful, while at other frequencies it is practically absent. On a spectrogram, this looks like a very sharp peak, and this is what distinguishes such signals from the result of natural processes. There, the radiation is strongly scattered over a fairly wide range.
The movement of plasma around stars
It is precisely this feature that seekers of alien signals have always counted on. But now it seems that this is not worth doing. Because, as they themselves have discovered, the plasma turbulence surrounding each star is capable of scattering artificial signals from planets. The peaks become wider and lower, which greatly complicates their search and identification.
Initially, this was a theoretical calculation, but then scientists were able to test this assumption using signals from Voyager 1, which had already flown far enough away from Earth. The result confirmed the scientists’ suspicions.
Now they believe that stars can hide artificial radio signals even more effectively than they thought. After all, 75% of them are red dwarfs, and these small stars are famous for their turbulent magnetosphere and flare activity. So perhaps we won’t hear aliens even if they are only a few dozen light-years away from us.
Provided by: phys.org
