Advanced alien civilizations haven't contacted us because of the age of our Sun
Believers in the Drake Equation may have found just the right explanation for why alien civilizations haven't been spotted by humanity yet. A new study published by U.S.-based researchers states that alien civilizations are likely looking for particular types of stars when trying to establish an intra-galactic base, and our Sun simply does not meet their criterion, Universe Today reported.
In the year 1950, Enrico Fermi and Michael Hart pointed out the huge gap in the application of the Drake Equation, the estimation of the number of civilizations in our galaxy. While the Drake Equation suggests a high mathematical probability for the existence of advanced alien civilizations, Fermi and Hart wondered why hadn't we spotted one yet. This was dubbed the Fermi Paradox.
SETI does not make sense
Years later, Hart published a detailed paper further analyzing the Paradox wherein he stated that civilizations could rapidly expand through a galaxy by sending out ships to the nearest 100 stars who would then repeat the process, enabling galaxy-wide expansion in a short period of time.
According to hart's calculations, our galaxy could be traversed in just 650,000 years, and an advanced civilization would have made contact with humanity by now. Since there haven't been any, Hart concluded there are no alien civilizations out there, and therefore, missions like Search for Extra-Terrestrial Intelligence (SETI) do not make sense.
The American astrophysicist also went on to state that if there was ever any attempt to colonize our Solar system, it would be by our descendants,
But what if the Sun isn't exciting?
In a paper that has recently been accepted by the Astrophysical Journal for publication, authors, Jacob Haqq-Misra and Thomas Fauchez from the Blue Marble Space Institute of Science and American University, respectively, point out flaws in the Fermi Paradox itself.
The authors state that since all stars in the galaxy are not the same, it makes sense if alien civilizations are a bit picky about where they would like to put up their colonies. Another study in 2021, had suggested that long-lived civilizations would rather pick the low-mass K and M-dwarf star systems to maximize their longevity in the galaxy.
Both K and M-dwarf stars are long-lived stars when compared to a yellow dwarf like our Sun. While this might not make a huge difference to humans, authors suggest that alien civilizations capable of colonizing solar systems would definitely take this into consideration while making their decisions.
Irrespective of the advanced stage of civilization, an attempt at colonizing a solar system would still involve the dedication of lots of resources, and civilization would not bet its resources on a star that would die out sooner, even if it meant by a few million years.
According to the researchers' estimates, an advanced civilization could take about two billion years to reach all low-mass stars, and there could be multiple civilizations attempting this right now in our own galaxy, something we can't write off just because we haven't spotted them. Programs like SETI could help us in this endeavor to spot them.
In our lifetimes, we would definitely not be able to replicate their success, but that does not mean we should not look for their signs either.
The paper was published in the Quarterly Journal of the Royal Astronomical Society.
An expanding civilization could rapidly spread through the galaxy, so the absence of extraterrestrial settlement in the solar system implies that such expansionist civilizations do not exist. This argument, often referred to as the Fermi paradox, typically assumes that expansion would proceed uniformly through the galaxy, but not all stellar types may be equally useful for a long-lived civilization. We suggest that low-mass stars, and K-dwarf stars in particular, would be ideal migration locations for civilizations that originate in a G-dwarf system. We use a modified form of the Drake Equation to show that expansion across all low-mass stars could be accomplished in 2 Gyr, which includes waiting time between expansion waves to allow for a close approach of a suitable destination star. This would require interstellar travel capabilities of no more than ∼0.3 ly to settle all M-dwarfs and ∼2 ly to settle all K-dwarfs. Even more rapid expansion could occur within 2 Myr, with travel requirements of ∼10 ly to settle all M-dwarfs and ∼50 ly to settle all K-dwarfs. The search for technosignatures in exoplanetary systems can help to place constraints on the presence of such a "low-mass Galactic Club" in the galaxy today.