¿We are looking for evil extraterrestrial life Or are we alone in the Universe? Some experts opt for the former. They believe that it would be quite egocentric to think that we are the only ones who inhabit the immensity of the cosmos. The problem is that we are busy searching for alien intelligence, but perhaps we are not smart enough to find it. Or, toning things down a bit, we haven’t found the best strategies. Normally we look for biosignatures or technosignatures. That is, biological traces or radio signals from some extraterrestrial technology. Now, astrobiologist Julia De Marines, from the University of California, Berkeley, has devised a new term that focuses right in the middle: noosignatures.
Smart, but not that advanced. If an extraterrestrial had landed its radio telescopes on Earth during the stone age I wouldn’t have found anything. I would have concluded that, in that direction, there are no planets with intelligent extraterrestrial life. The failure would have been in thinking that any planet with intelligent life must be at the same point of technological development. Seen this way, it is a pretty big mistake. But the reality is that we are doing just that. For this reason, De Marines believes that technofirms are not the best options.
As to biosignaturesdo not always point to biological processes. The history of space exploration is full of examples in which it cannot be ruled out that the biosignature has a geological origin. In fact, it is most likely. For this reason, this astrobiologist proposes that intermediate point in which life is not sought, but rather intelligent activity at an intermediate point before developing advanced technologies. Because it may not have been sought at the right time or, simply, that civilization may not have advanced that much. To be able to detect it correctly, the key is in Assembly Theory.
Too many pieces to put together alone. Assembly Theory is based on the assembly index of an object. That is, the number of pieces that had to be joined to form it. Sometimes pieces can be assembled by natural processes. However, above a certain threshold, a complexity is denoted that can only have certain intelligent activity behind it. Stone age tools are a good example.
No need to look for stone axes. Although we take prehistoric tools as an example, this cannot be sought by launching telescopes and sensors into space. However, there are activities that can be measured from the outside. For example, agriculture left a measurable trace of nitrogen in our atmosphere. Even food manufacturing, such as fermented products, can be detected in waste chemistry thousands of years later.
It is not necessary to understand it. Something important about this method of searching for extraterrestrial life is that it is not necessary to understand noosignatures. Returning to examples from our own history, in Phys point out the case of the Indus Valley writing. At the moment, no one has been able to decipher it, but we know that it was not written alone. There was an intelligent mind behind it. In this case the same thing happens. We must look for traces that do not fit with the natural behavior of the planet, even if it is not understood how they could have arisen.
The limitations. This method of searching for extraterrestrial life has a major limitation. And noosignatures are ephemeral. If they are not measured at the right time, they can disappear. Additionally, they can be quite complex to decipher. To all this we must add that the study published by De Marines is a preprint. This means that it has not yet undergone review by an independent research team. Therefore, we must take their approaches with a grain of salt.
Anyway, the reality is that, since the beginnings of SETIthe search for intelligent extraterrestrial life is not bearing good fruit. Not even the search for life, in general. The twists in methodology can be interesting, so this one deserves, at the very least, the attention of other astrobiologists.
Image | Brooke Denevan (Unsplash)
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