Many people ask this question often that if we have aliens then why we have not been able to find the aliens till date. While today we can easily see the stars for millions of light years away. We could not find any aliens anywhere. We know today that we have not been able to find the aliens till date.
Astrophysicists have to remove all their information only by keeping in mind the light coming from a star. All this work is done by supercomputers. Note here that if there are aliens then they will not be on any star, but on its planets. For this reason, if we have to find out what is there, then it will be the only way that we can go there and find out. If they are an advanced civilization and they are also looking for a life in the universe and they respond to the signals sent to us. Or else he sent a signal and if we could catch his signal then we can find out.
The problem is that if we want to go out of the solar system, today's technology will take us several thousand years. If we talk about the radio signals we send, then they also move at the speed of light speed. If an alien advanced civilization is thousands of light years away from us, it will take thousands of years to reach our message and their response will take thousands of years, even though we have just started it a few years ago.
If someone is a very advanced civilization and if we use any other communication signal instead of radio signals, then we will not even be able to know and neither will they be able to see us about them.