Is anyone listening? We risk waiting for 400,000 years

If there are so many galaxies, stars, and planets, where are all the aliens and other intelligent life forms, and why haven’t we heard of them before?

These are the simple questions at the heart of the Fermi Paradox, and it is precisely the question of why, despite everything This Life We couldn’t find it in space. In a new article, two researchers ask the following obvious question: How long will we have to survive hearing the voice or data of another space civilization?

their answer? A little long, 400,000 years old. 400,000 years is a long time for species that existed 200,000 years ago that only discovered agriculture about 12,000 years ago. But 400,000 years is the time we will need to continue this human experiment if we are to get news of alien civilizations. This is the result of the latest study on communications with additional Earth intelligence, CETI.

document “The number of potential CETIs within our galaxy and the probability of communication between these CETIsThe authors are Wenjie Song and He Gao, both from the Department of Astronomy at Beijing Normal University. The article was published in The Astrophysical Journal.

“As the only advanced intelligent civilization on Earth, one of the most confusing questions for humans is whether our existence is unique,” the authors say.

“There have been many studies of an extraterrestrial civilization in the past few decades.”

It certainly was there, even if it is difficult to study something we are not sure of. But this does not stop us.

Studying other civilizations in any way is confusing because we only have one data point: humans on Earth. However, many researchers have treated this issue as a kind of thought experiment, using strict scientific guidelines. A 2020 study, for example, concluded that there are likely 36 CETIs in the Milky Way.

The number of CETIs there is depends on how long we may have to wait to hear one. We have always wanted to know the answers to the following questions. First, how many CETIs are there in the Milky Way? This is a difficult question that we can only learn from one known data point (ourselves),” the authors wrote.

This is where you play Drake equation. This is the theoretical equation that counts the number of extraterrestrial civilizations at the same time as ours. Based on our increasing knowledge of the Milky Way, the Drake equation attempts to estimate how many ETCs there are in our galaxy.

The Drake equation has its drawbacks, as many critics have pointed out. For example, some of its variants are little more than guesswork, so the number of civilizations it calculates is unreliable. But the Drake Equation is more of a thought experiment than an actual computation. We have to start somewhere, and that’s what gets us started.

“Most studies on this problem are based on the Drake equation,” the researchers wrote. “The obvious difficulty with this method is that it is too uncertain and unpredictable to determine the likelihood of life emerging on a suitable planet and eventually evolving into an advanced communicating civilization.” If you doubt all this, you are not alone. We can’t scientifically know how many other civilizations there are, or even if there are. We don’t know enough. Studies like this are part of an ongoing conversation with ourselves about our plight. Each helps us think in the context of our civilization.

So how did they get to 400,000 years ago if we don’t even know how many CETIs there are?

The research duo are not the first to address this question. Their article outlines some of the previous scientific efforts to understand the spread of other civilizations in the Milky Way. For example, they point to a 2020 study estimating that there are 36 CETIs in the Milky Way.

This number came from calculations that included galactic star formation dates, metallicity distributions, and the probability that stars host Earth-like planets in their habitable zones.

This document states that[Il] The topic of intelligent and communicative extraterrestrial civilizations will remain entirely in the field of hypotheses until a positive survey is conducted.”

But they also point out that scientists can still produce valuable models based on reasonable assumptions that “can at least produce reasonable estimates of the rate at which such civilizations will occur.”

This study bears some of the same thinking. These are two parameters, both of which are unknown. The first relates to the number of habitable terrestrial planets and how often life on these planets evolves to CETI. The second is at what stage of host star evolution a CETI can be born.

The researchers assigned each of these parameters a variable in their calculations. The probability of life appearing and evolving in CETI is (fc) and the required host star evolution stage is (F).

Song and Gao ran a series of Monte Carlo simulations using different values ​​for these variables. They came up with two scenarios: an optimistic perspective and a pessimistic one.

The optimistic scenario used F = 25 percent and fc = 0.1 percent. So a star must spend at least 25% of his life before CETI appears. And for every terrestrial planet, there is only a 0.1% chance of a CETI occurrence.

These optimistic variables create over 42,000 CETI points, which seems like quite a lot, but isn’t spread across the galaxy at different times. Furthermore, we will need to survive another 2,000 years to achieve two-way communication. It almost seems within reach.

But this is the optimistic scenario that makes the universe seem friendly and inhabited by other welcoming civilizations. Maybe some of them are already talking to each other and we just need to meet.

Now for the pessimistic scenario.

In the pessimistic scenario, F = 75 percent and fc = 0.001 percent. So a star cannot host CETI until it is much older and the probability of a single Earth planet hosting CETI drops to a tiny fraction. Where will this lead us!?

This pessimistic calculation results in about 111 CETIs in the Milky Way. Even worse, we would need to survive another 400,000 years to have two-way communication with them.

This is where the Great Filter comes into play. A great filter is anything that prevents matter from becoming life and then progressing to become an advanced civilization. The authors address this topic when they write:

“However, it has been suggested that the lives of civilizations are likely self-limiting, due to many potential disruptions, such as demographic problems, nuclear annihilation, sudden climate change, rogue comets, environmental changes, etc. If Doomsday’s argument is correct, in some situations Pessimistic, humans may not have received any signals from other CETIs prior to extinction.”

The scientists wrote in their article that “the values ​​of fc and F are filled with many unknowns”. This is the case in all this type of work. This article, and others that address the same question, are viewed more as thought experiments than solid findings.

We can’t know any of these things for sure, but we can’t help but be compelled to explore them. It is part of human nature.

They wrote: “It is not entirely certain what proportion of terrestrial planets could give life to life, and the process of life evolution at CETI and the ability to send detectable signals into space is highly unpredictable.”

Will humanity meet another civilization? It’s one of our most pressing questions, and almost certainly no one alive today will have an answer.

First, there have to be other CETIs, so we have to be with them at the same time and communicate in some way. It is possible that other CETIs may have already discovered the existence of life on Earth before it was wiped out by the Great Filter or perhaps by a natural disaster such as a supernova explosion. We will never know.

Perhaps humanity will survive for a long time. Perhaps the Earth will become uninhabitable and humanity will flee to Mars or somewhere else. But could Mocian’s location on a long-dead planet inhabited by muddy descendants of the devastated Earth be considered a CETI?

We like to imagine that other civilizations have successfully overcome the problems we still struggle with. Could it be true? Or will the first CETI we find be little more than the descendants of a once proud civilization that radiated confidence until the Great Filter hit?

Who do you know? If humanity encounters another technological species, it may be so far into the future that our descendants are nearly unrecognizable to modern humans.

Or maybe we will never have an answer and the great filter will prevent us from finding an answer.

But if humanity needs a purpose, something to hold on to that can keep hope alive, another CETI dream is possible.

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