Is there life on other planets? It is possible. And that is really where the problem lies. No one on Earth really knows or is likely to find out in the near future.
We have learned about the beauty and diversity of space with its galaxies, planets, stars and other phenomena. Its origin and development are based on the principal laws of physics. The development of life requires the light and heat of a sun, which must not be too big or so small, so that its life span is not too short or its energy too weak.
These conditions are met by several planets, but that, on its own, is not enough. A gaseous planet could, for example, not support life. A solid planet would be suitable, but it would have to be of a suitable mass to hold an atmosphere. It would also have to be at a certain distance from the sun, so that it neither burns up nor cools down too much.
Is it not possible that a planet similar to the Earth could have formed somewhere? Are we really alone in the Milky_Way? After all, primitive life forms were discovered in old rocks on Mars.
In order to err on the safe side, messages from man to extraterrestrial life were placed on board the Voyager probes, in the hope that, if found, they would be understood. One plaque depicts a man and a woman, the solar system, the flight path of the probe and a means of calculating the time between launch and discovery of the message. There are also recordings of music and speech in different languages as well as pictures of Earth on board.
Astronomers have estimated the total number of planets in the Milky Way to be about 60 billion. A small portion of these is believed to be similar to the Earth, with water and temperatures that would allow for the development of life.
If extraterrestrial life exists, why can we not receive messages from such beings? Perhaps they know nothing of our existence. Or, perhaps the electromagnetic signals sent by man do not reach them because they are too far away. Maybe these beings, if they exist, do not even want to communicate with us.
For most of the solar and planetary systems, the purely theoretical possibility of the existence of life of whatever description must be seriously considered.
