03 Jun , 23:16
0
The first life discovered beyond the Solar System may turn out to be far from typical for the Universe. This is the conclusion reached by scientists from the Goddard Space Flight Center (NASA), who analyzed patterns of first astronomical discoveries throughout the history of science.
This was reported by the Universe Today (UT) portal.
The authors of the study draw attention to a paradox that has repeated itself time and again in astronomy: scientists first find not the most common objects, but the most conspicuous ones. The first confirmed exoplanet was discovered not around an ordinary star, but near a pulsar — an extremely exotic and rare object. The first discovered quasar turned out to be the brightest one visible from Earth, and the so-called "hot Jupiters," after their discovery, long created the false impression that such planets were found at every turn.
According to the researchers, the search for extraterrestrial life will inevitably fall into the same trap. Modern telescopes can detect only the most powerful signals, meaning the first biosignatures — chemical traces of life in the atmospheres of exoplanets — will most likely be detected not on typical habitable worlds, but on those where they are easiest to spot.
The James Webb Space Telescope plays a key role in this search. It studies exoplanet atmospheres by analyzing starlight passing through a planet's gaseous envelope as it transits across the star's disk.
Sub-Neptunes — planets larger than Earth enveloped in dense hydrogen atmospheres — turn out to be the most "readable" for such observations. Thanks to their impressive size and the characteristics of their gaseous envelopes, they produce far more pronounced spectral signals than Earth-type planets.
As an illustrative example, the scientists cite exoplanet K2-18b, located approximately 124 light-years from Earth. It exceeds our planet in size by roughly 2.6 times and is considered one of the most promising candidates for biosignature detection. According to the authors' calculations, a potential signal of signs of life from such a planet could be approximately 32 times stronger than from a complete analog of Earth.
The researchers emphasize that the question of K2-18b's habitability remains a subject of intense scientific debate. However, the planet itself perfectly illustrates the main problem: the most conspicuous objects are far from always the most typical ones.
In the opinion of the study's authors, the detection of the first biosignature will become one of the greatest scientific discoveries in human history. However, the scientists warn: if the first signs of extraterrestrial life turn out to be unusual and completely unlike those on Earth, there should be no surprise. And conversely — even if they resemble conditions on our planet, this does not necessarily mean that such life predominates in the Universe.
