The article is based on the lecture of Prof. Yoav Yair from the Department of Natural and Life Sciences at the Open University as part of the Scientists' Night 2013
As I mentioned yesterday, One of the interesting lectures as part of the Night of Scientists events was the lecture by Prof. Yoav Yair at the Open University campus in Ra'anana that took place last Thursday. We bring its content to the surfers of the knowledge website courtesy of Prof. Yair.
Prof. Yair defined the subject as an intellectual exercise designed to think about the event of an encounter with aliens, even if the probability is low it would be interesting to discuss its consequences.
"In this context, two questions are asked, I will only address the second one, because the answer to the first question - is there life somewhere in the solar system or in the universe, the answer is yes. The second question is, is there in the universe today (with an emphasis on 'now') an intelligent communicative culture with which we can establish contact or at least contact? And also do they come here."
Drake equation - for estimating the number of intelligent civilizations in the universe
The tool for estimating the probability of finding intelligent life in space was invented in 1961 by Frank Drake with the aim of giving a preliminary estimate of the outer media cultures that exist in the galaxy today. The equation contains relative probabilities of several astronomical parameters, some of which can be measured and others - only conjectured. By delimiting the estimates according to 'optimistic estimates' and 'pessimistic estimates', it is possible to obtain a definitive and defined number that gives a quantitative value.
The number of technologically intelligent civilizations in our galaxy is the product of a series of numbers, probabilities that include the following data: How many sun-like stars are formed in our galaxy. This is astronomical information that can be known; If there are sun-like stars, some of them have planets around them. We know that we live on one of the eight planets in the solar system. Until 20 years ago we thought that our solar system was the only one, today we know of at least 700 more planets (and this is mainly from measuring a very limited area in space by the Kepler spacecraft), at least some of them are similar to Earth (rocky planets).
Decomposing the equation
If there are other solar systems with planets similar to Earth, how many of them even have life? We don't know either, we can guess, maybe one in a thousand? One in a hundred thousand?
We then have to ask the question how many of these species are intelligent? There can be planets with different types of life forms on them corresponding to fungi, spores, algae, ferns. This is biological but not intelligent life.
The next question is if there is already intelligent life, have they developed technology that enables interstellar travel? The pharaohs, for example, were an intelligent species, they built pyramids and made Moses and the children of Israel work hard, but they did not fly into space. The question is how long does it take for an intelligent civilization to develop the technology that would allow it to communicate across galactic distances and the last question is how long does such a civilization survive? This is a question we don't know the answer to, because we only have one example.
Let's do some calculations for each of the shoes in the equation. Regarding planets outside the solar system - 676 solar systems are known today, and in them more than 859 planets (128 stars have more than one planet). Most of them are of the 'hot Jupiter' type, but there are also some with rocky planets in the life zone. The conclusion - there are many places similar to us. We can measure the temperature and composition of the atmosphere and identify for example water vapor.
Where is everybody?
Let's make a conservative assumption that there are a thousand places in the galaxy that have a technological communication culture. The big question is where are they all? A question known as the Fermi paradox. This question has several possible answers. One is the "principle of mediocrity": we don't really interest them; Another reason is the "rare land": we are the first / the only ones / they are extinct; Another possibility is the "zoo principle": they watch us, do not interfere; Alternatively, they haven't arrived yet, or they simply missed us; Another interesting approach is that, in fact, we are the result of the invasion! (was in the past); And of course there is always the possibility that the technological difficulty to reach / transmit is too great; Or alternatively they visit but we just don't see them except for a few virtuous individuals and secret keepers - all the conspiracy theories of the type that can be found in black' or 'cases in the dark'.
According to the reports of all kinds of alleged witnesses who have claimed to have seen/encountered/been abducted, there are several different levels of possible encounters with aliens. The first type is simply watching a UFO from a close range, without its effect on the environment; The second type: like the first type but with an effect, for example on cars and the like (electrical effects, signs of fire); The third type: aliens can be observed inside the UFO or in its immediate vicinity, but not necessarily while interacting with them; The fourth type: Kidnapping: invitation/taking by force and return. The aliens perform medical experiments, invasive tests, implants. And finally, the fifth type: a one-way ticket: You are beamed up never to return
What do we do in the event of an alien invasion?
In light of all this, one of the options is an invasion - they come, land on the lawn of the White House or the Knesset and say - surrender. But as we know, this did not happen. 99.99% and more of the reports can be explained simply as hallucinations or optical illusions; Some of them are pranks, scams and acts of cheating, ("Zomi" search) and others are simply incorrect explanations of natural phenomena such as clouds of various types, meteors and in particular those of them that are fireballs; Nearby planets (Venus) or atmospheric optics tricks and of course military systems that were secret at the time such as drones and balloons (as we saw not long ago - the aliens will have to wait. The CIA revealed documents about Area 51 and nothing to do with aliens https://www.hayadan. org.il/cias-declassified-documents-reveals-secrets-about-area-51-and-ufos-1706138/)
What would extraterrestrial life forms be made of?
Life everywhere will be based on the most common elements in the universe: hydrogen, helium, carbon, nitrogen and oxygen - formed inside stars in nuclear processes and the most common in the universe. It is likely that if life were to form in an extrasolar system, it would be based on these elements and not on rare compounds. But they will not necessarily be similar to us (gravitation is different, the composition of the atmosphere is not similar to ours, their evolution will certainly be different)
Some assumptions about technological cultures
The extraterrestrial culture could be: the top step in the planetary food pyramid - super-carnivores (like us), if they have traveled all the way through space to us, it is most likely a much more advanced culture than us technologically, scientifically, morally, and maybe we will find cultures that are at about the same stage of development as us.
Despite the enormous technological progress in the last hundred years, there may be a limit to the degree of development of an intelligent species. This means that a million-year-old culture will not necessarily be much more advanced than us.
And they came and decided to invade, how will we recognize their intentions? Again it is a range of possibilities starting from the utilization of the planet's resources: water and minerals; destroying and thwarting future threats from us; labor (labor) or food; colonization: new settlement; Asylum seekers / interstellar refugees. It is also possible that contact is accidental and unplanned or they are just conducting scientific research: another butterfly for the collection.
Assuming the invaders have complete technological superiority - if they have already reached interstellar flight capability and arrived here, then they are much more advanced than us and therefore the chance of surviving an attack is slim. However, the science fiction films showed that it would be possible to use asymmetric warfare (guerrilla) against them, to disperse the means of warfare in the jungles, to cut off their supply and communication lines, and perhaps locate their Achilles' heel.
What is the probability of finding a peace-loving extraterrestrial intelligence? The naive beliefs in the good intentions of the invaders do not stand the test of human history: for example, Cortez and the Aztecs in South America, who surrendered to him due to superior power but also due to the belief that people who come riding on an animal are gods. Also, most of the Indians died because they contracted the flu from the Spaniards who were not vaccinated against it.
The next issue is should we make contact with an extraterrestrial culture? In fact we already did. The Voyager 2 spacecraft launched in 1977 carried with it a golden CD with scientific, mathematical and astronomical messages about human culture. The spacecraft has already left the solar system and is moving in the galaxy (see news from yesterday https://www.hayadan.org.il/voyager-1-lteft-solar-system-1309130/. In another 40,000 years it will pass by another star (sun). ..and if there is someone there, maybe he will catch the spaceship. Assuming he decodes the message, how long will it take for his answer to arrive?
listening to the radio
And of course the most common option is the radio broadcasts, As it appears, for example, in the book "Contact" According to Carl Sagan: It is clear that in the vast distances between the stars, contact can only be made by radio transmissions; We are leaking into space unintended radio noise from the last century... the signals have already spread to a range of 80 light years from here.
As for searching for radio signals, the question is whether the search should be passive or also active - that is, broadcast out? Who is authorized to broadcast on behalf of the human race? What to broadcast? How to mark our intentions? How will we communicate with them?
This is where the set of SETI searches based on detecting transmissions in the electromagnetic spectrum comes into play. As part of it, the distributed computing project SETI@home also operates: billions of hours of computing signals.
So far, after 20 years of searching, no signals have yet been found in the radio field that would testify to an encrypted transmitter of an intelligent culture. On the other hand, it is possible that intelligent cultures do not transmit at all in the radio field, for protection purposes.
Our possible reactions in case of indirect contact: assuming there will be no physical encounter, it is about decoding a signal that is not "natural noise". We need to find out if this is a deliberate signal or just an administrative broadcast? If the signal is complex and complicated, a scientific dispute is expected - see for example the issue of global warming; Is a sweeping denial expected from religious and political establishments, among other things, for fear of undermining the existing order?
How to prepare for contact with extraterrestrial intelligence?
Here the four principles of Alan Goodman from Georgetown University (1985) come to our aid:
- Whoever finds evidence of contact will publish it
- Any answer will be made after international consultation
- Aliens who arrive will be considered diplomatic envoys
- If it turns out that the aliens are a threat, no country will act without the approval of the UN Security Council
In the same context, there is also the SETI contact protocol that examines certainty and verification and ensures the application of universal principles such as the right to self-defense
In conclusion Prof. Yair says: There is life in the galaxy, but the probability of meeting is low. Unfortunately, they still haven't arrived or called, but we're not ready!
More on the subject on the science website (and this is only a part)
- Why are there apparently no aliens?
- Review of the film Contact based on Carl Sagan's book
- Hello, is this Bloomfield? Or how we will communicate with intelligent aliens
- The enduring fascination of the Roswell incident is indicative of the way we will respond when real aliens land here
- How do you make contact with other life forms in space?
- Carl Sagan - Knowledge is our destiny, intelligence on Earth and beyond
- What will our first encounter with extraterrestrials look like?
- What do the aliens look like?
- A question in the Knesset - have UFOs landed in Israel?
- How long will it take to reach the nearest solar system?