In April 2020, all those listening to the "voices of heaven" and waiting for messages from other civilizations celebrated an important anniversary. Exactly 60 years ago, American radio astronomers caught what seemed then to be ordered signals from the star Tau in the constellation Cetus. By that time, scientists already knew that Tau Ceti was very similar to our Sun in color, surface temperature and many other characteristics. Is that slightly smaller in size. How could you not decide that an "earth-like" planet revolves around the "sun-like" star, and its inhabitants send us their greetings and proposals for cosmic friendship?
And they send us back …
After that, throughout the 1960s, the media enthusiastically discussed the possibilities of contact with other civilizations that could be provided by the rapidly developing radio astronomy. The appearance of space "brothers in mind" - LGM, Little Green Men (little green men) was even invented.
The popular Soviet editions "Science and Life" and "Technology for Youth" also paid attention to this topic. Without making any overly optimistic statements, they briefly reported: “On April 8, 1960, the American scientist Frank Drake at the Green Bank Observatory (West Virginia) received signals from the star Tau Ceti using a 26-meter radio telescope. The data is analyzed, the nature of the signals is being clarified."
However, even such restrained information served as an excuse for the heroes of science fiction novels to begin en masse to go to Tau Ceti. In addition, there was nothing to fly to the star - about 12 light years.
Therefore, Vladimir Vysotsky wrote about one of his most famous songs "In the distant constellation of Tau Kita". It begins with the words:
Unfortunately, the hypothesis about the artificial origin of the signals from the Tau Ceti was not confirmed. Nobody sent us back.
However, does this mean that there is no life on the planets of Tau Ceti?
Live in beauty on Tau Kit
As they say, there is no direct evidence - look for indirect evidence. What do we even know about the star Tau Ceti, confirming (or refuting) the hypothesis of the presence of life on its planets?
So, Tau Ceti is a fairly bright yellow star like our Sun (or, as astronomers say, spectral class G). There are not so many such yellow stars in the Universe, only three or four per hundred. The star Alpha Centauri, which is closer to us, also belongs to spectral class G. But the trouble is that it is triple. It is very difficult, you know, to develop on a planet under the gravitational influence of three suns at once.
But Tau Ceti, like our Sun, is a single star. Its electromagnetic radiation is relatively stable, which is also very important for the development of life. The spectrum of the star indicates that there may be terrestrial planets in its system - another important fact for our search for "circumstantial evidence".
The fact is that the planets of other stars (they are also called exoplanets) for the most part turn out to be similar not to Earth, but to Jupiter or Neptune. The overwhelming majority of the thousands of exoplanets known to date are gas giants. The likelihood of the emergence of life on such planets with their monstrous pressure, the absence of a solid surface and a poisonous hydrogen-ammonia or hydrogen-methane atmosphere, to put it mildly, is negligible. In any case, life, at least somewhat reminiscent of ours.
But if Tau Ceti has planets, then the conditions on them can be quite favorable for the development of higher organisms. Perhaps even more comfortable than ours.
Are the conditions on Tau Kita wrong?
Indirect evidence is therefore indirect, because when listing them, you have to use the words "if", "possible", "presumably" all the time.
Before looking for an answer to the question of how the Taukitians live on their planets, it would be good to make sure that these planets really exist; that they are of a suitable, terrestrial type and are in the so-called zone of life - not too close and not too far from the star. And only then, as the hero of Vysotsky, make assumptions: "They live in beauty on Tau Kita, by the way, our comrades in mind live in different ways" or "on Tau Kita the conditions are not the same - there is no atmosphere, it is stuffy here …" …
Astronomers determine the presence of a planetary system in a star in different ways - for example, by the periodic change in the optical brightness of the star when the planet passes in front of the star, partially obscuring its brightness, or by the features of radio emission.
In 2012, an international group of astronomers led by Mikko Tuomi from the University of Hertfordshire (UK) developed a new method for measuring the "radial velocities" of stars - that is, the speeds of movement "to and from the observer". The method makes it possible to measure the lightest, up to several meters per second, changes in the radial velocity of a star. These changes are believed to be caused by the gravity of the planets. The method was tested on the Tau Ceti star and gave impressive results.
It turned out that the star really has a planetary system! Tau Ceti has at least five planets. All of them are not gas giants, but quite terrestrial. And, perhaps, one or two of these planets are in the zone of life.
By 2017, observations of Tau Ceti had already yielded more definite and encouraging results.
Here, moving along a light beam …
The existence of three of the previously discovered planets was not confirmed, but two new ones were found. It is currently believed that there are four planets in the Tau Ceti system - g, h, e, f.
In the zone of life, most likely, there is one earth-like planet - Tau Ceti e. It is 3, 9 times heavier than the Earth and rotates closer to its star, so that the year on it is only 163 days. But, despite the increased severity and heat (due to the proximity to the luminary), it is on this planet that life is possible. It all depends on what kind of atmosphere the planet has. Optimists among scientists are inclined to believe that the atmosphere is nitrogen-oxygen, like on Earth. If so, the planet Tau Ceti e has a very high Earth Similarity Index (ESI) of 0.77.
In addition, it is located relatively close - 11, 9 light years.
All of this makes the planet the "# 1 candidate" for future interstellar travel. Since the Taukites do not send us any meaningful signals, we must, firstly, make sure of their existence, and secondly, understand why they behave this way. Perhaps Vysotsky was right and the Taukityans simply do not care about us:
But how realistic is it for humanity to overcome such a small, in cosmic scale, distance - 12 light years? The fastest Voyager spacecraft have a speed of less than 18 km / s, so the journey to Tau Ceti would take 212,000 years. Now, if, like the hero of Vysotsky, move "along the beam of light" …
However, is such a project really so fantastic? There are scientists who believe it is quite feasible, and in the near future. But we need to develop more efficient technologies.
One of the members of the research team that discovered the Tau Ceti system, Paul Gilster, is very optimistic: “A spacecraft under a“light sail”, propelled by laser or microwave pulses, can reach a speed equal to 10% of the speed of light in a short time. Today, this is no longer a fantasy, and I am sure that very soon travel to distant worlds will become a completely mundane activity. The flight to Tau Kita e under the "light sail" would take only some 100 years."
