We have been unintentionally transmitting various signals and sounds to the space through radar, satellites and radio signals. It creates various bubbles of radio energy getting out from the Earth at the light speed. The end of 20th century, it was calculated that the diameter of this bubble goes beyond 100 light years and civilizations within the sphere of radio rays gives a hinting that we belong to this place.
SETI have accounted that extraterrestrials are not visiting us because they have already moved ahead of us and listen to broadcasting from our radio and TV channels. They don’t see intelligent life on Earth and it is joked that this is the reason for them not to show their presence. There are a few messages sent in the universe intentionally by scientists. These coded messages are sent to different clusters to provoke the other side to get back with some message or signal. It was estimated that the message will take about 25K years to reach to the great distance of cluster. The messages sent are in binary notes (0 &1) and contained 1679 bits of information.
There are many haphazard messages sent in the universe with combination of binary digits. There are interesting patterns emerging from these combinational numbers and it is based on the thinking that there will be some bodies looking for signals from the planet Earth. The messages are expected to reach the target cluster after tens thousands of years and the transmission reminds us that we want to know about the other people living in the planet.
There is no surety about anything related to aliens, but they have given several signals on the planet Earth about their presence. We can’t be sure that they are looking for us or we look ahead to know about them.