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Here on Earth, we experience poor signal reception all the time. The most common example is the frustrating experience of trying to talk on your phone in an area with poor reception.
In certain buildings, the reception may be bad due to the materials of the building, and it can get bad enough to block cell signals or even radio waves.
A new study published in The Astrophysical Journal suggests that a very similar issue may explain the reason why we aren’t getting any signals from aliens throughout the universe (assuming they exist).
Currently, the team at the Search for Extra-Terrestrial Intelligence (SETI) scans for narrow bands of signals coming from space and looks for any type of signal that doesn’t seem to have a natural origin.
They look specifically for wavelengths that they think aliens would be likely to choose (which is a difficult thing to predict anyway, since we would know little about them).
What hasn’t been considered in the past, but should be, according to the study authors, SETI’s Dr. Vishal Gajjar and Grayce C Brown, is that these signals aren’t truly just passing through the vacuum of space and nothing else.
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They have to pass through the turbulent plasma from not just our star, but the star of the signal’s origin, and potentially other sources of plasma.
That plasma broadens out the wavelength of whatever signal is sent, causing it to become wider. Since we generally only scan for narrow wavelengths because they would be what is likely sent, we may be missing the type of signal that arrives. In a statement on this, Gajjar said:
“SETI searches are often optimized for extremely narrow signals. If a signal gets broadened by its own star’s environment, it can slip below our detection thresholds, even if it’s there, potentially helping explain some of the radio silence we’ve seen in technosignature searches.”
As part of the study, the team worked to determine how much ‘smearing’ of the wavelengths would likely occur. This was estimated based on the known effects of our local solar wind on signals sent and received by spacecraft.
The amount of ‘smearing’ would depend greatly on what type of star the planet of origin is near, how close it is to that star, and many other factors. Gajjar explained:
“Stars are very active. They have winds, they have coronal mass ejections. So what we were able to conclude is that some of these effects can completely wipe out any possible technosignature we can detect.”
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Taking this paper into account, SETI can make adjustments on what types of signals they are monitoring for and, hopefully, detect any alien communication that may be there. In the statement, Brown said:
“By quantifying how stellar activity can reshape narrowband signals, we can design searches that are better matched to what actually arrives at Earth, not just what might be transmitted.”
Wouldn’t it be funny, or maybe just frustrating, if for the last several decades we’ve been trying to pick up a signal from space and the problem has been something as well-known as signal interference?
If you deal with anxiety, check out this post about the “empty boat theory,” which proves that no one is thinking about you most of the time.