Earth is the only known planet in the solar system where life exists. However, scientists have discovered many planets outside our solar system which lie in the habitable zone, and sometimes, these rocky bodies might also possess intelligent life forms just like us. If alien life exists in these space bodies, they might be also looking for their cosmic neighbors, and one day, they may locate us as we are sending enough signals to space which signals our existence.
Let us now check out three ways through which aliens could detect life on earth in their search to locate planetary neighbors.
The presence of gases
Without the presence of gases, life on any planet is practically impossible. It should be noted that scientists, here on earth have indicated that alien life may be hidden in Saturn's moon Enceladus. Scientists have made this conclusion after finding traces of methane in the surface of Enceladus. According to the research team who took part in the study, these traces of methane could be produced by microbial life forms living in the warm underground ocean of Enceladus.
In the same way, alien life forms who are as intelligent as us would be looking for the presence of gases in our solar system. Once they detect the location of the earth is the habitable zone, they will be looking for the presence of elements like oxygen and other life-sustaining elements. As aliens discover oxygen and other elements like carbon dioxide, nitrous oxide, and methane, they will assume that earth is one potential planet where life exists.
Advanced alien technologies
If aliens in deep space are more advanced than us, they will be possessing telescopes which are highly sophisticated, and it might help them to map earth's surface from a huge distance. Using advanced telescopes, aliens might be able to analyze the regional difference across the earth's terrain, and thus they would be able to see the signs of life.
Interestingly, in the earth, scientists are planning to develop a telescope called ELF (Exolife Finder) which will help them to analyze the terrain of distant planets.
Humans are giving aliens a signal
We are sending a number of satellites to our orbit for various needs, and sometimes, these artificial bodies might act as biomarkers which hint at our existence.
Moreover, humans have been sending radio waves to deep space to proclaim our existence, and sometimes, it might get caught by extraterrestrials. However, considering the vastness of space, the radio waves which we have sent might be still traveling, and it may not reach an advanced alien civilization in the recent future.