There's a topic in science fiction that never goes out of style
That is a topic related to aliens, because so far human civilization has never found aliens in the universe, whether it is Mars, which has been pinned high hopes, or many super-Earths that have been discovered so far, there is no trace of aliens or alien civilizations on it, but this does not prevent many people from believing that aliens exist.
Because our universe is so big, and the Earth and the solar system are too ordinary.
There is currently no evidence that the solar system and the Earth's environment are unique, in the 93 billion light-year diameter observable universe, astronomers estimate that there are at least 2 trillion galaxies, each galaxy has at least 100 billion stars, each star carries at least one planet, so many numbers multiplied we are not difficult to find: Earth is not special, planets like Earth in the stellar habitable zone abound, and the evolution of Earth-like life can also occur on other planets.
But the key question that entails is: If one day we do discover an alien civilization, or if we are discovered by an alien civilization, how will the two sides communicate?
First of all, it is certain that the contact between alien civilizations and humans is certainly different from the contact between two tribes on Earth in ancient times, because all human beings are of the same origin, using sound and vision to communicate, and for alien civilizations hundreds of light-years away from Earth, the biological gap between them and humans will reach the door level or even the boundary level.
In other words, the way of communication within alien civilizations would be completely unimaginable to humans, they may not even have eyes and ears, and thus will not receive visible light and sound waves.
Therefore, communication with aliens can only use certain regular signals that intelligent civilizations have, such as mathematics.
In 1974, the astronomers launched the Arecibo message, which used the mathematical form of binary encoding to broadcast most of the information of human civilization to the universe, so that it could be received and deciphered by any civilization that mastered the binary, but due to the speed of light, the Arecibo information has only been spread for 48 light years so far.
Today, in the 21st century, a team of NASA scientists and Chinese scientists has conceived a "Find Friends Information" called the Galactic Lighthouse, which consists of 13 parts and aims to summarize the position of human civilization and the earth with the shortest information, and the coding method used in this information is the simplest custom bitmap "alphabet".
The message begins with a prime number, indicating the sender's intelligent civilization identity, then uses the alphabet to elicit the decimal and elementary mathematics of human civilization, and finally uses the energy level transition law of the hydrogen atom to represent time, thus marking the time of sending this information and a number of elements that humans have discovered.
Since mathematics is a tool that cosmic civilizations will know and touch, and hydrogen is the most abundant element in the universe, the scientific community believes that this galactic beacon information must be understood by alien civilizations.
Like the gilded disks of previous Voyagers and aresipbo information, the Galactic Beacon information concludes with a basic image of individual human civilization, as well as of the entire solar system and Earth, and also uses pulsar positioning to accurately mark The Earth's position relative to other stars in the Milky Way, as well as the radio frequencies that alien civilizations can use if they want to reply.
No exaggeration
Galactic Lighthouse information is the most detailed summary of human civilization ever recorded, but it is still a bit difficult to use it to connect with alien civilizations, because even the most delicate information can only travel at the speed of light.
In the case of a solar system radius of one light-year and a diameter of 180,000 light-years in the Milky Way, unless aliens drive a spaceship to wait for rabbits near the solar system, it is impossible for the Galactic Lighthouse information to be received by an alien civilization across tens of thousands of light-years, and even if it is received, it is tens of thousands of years later, and it is difficult to say whether humans are still in the solar system at that time.
It is worth mentioning
The Galactic Beacon Information, which will be launched soon, will be launched by the continental FAST Radio Telescope, which will send information to the central region of the Milky Way 18,000 light-years away by installing a launch module, because there are dense globular clusters there, and the probability of life and civilization is relatively high.
As for whether the information will attract aliens after launch, whether it will attract aliens with good intentions or malicious intentions, this is not what we need to worry about.