If we do find evidence of alien life, this civilization will either be way behind or way ahead of our scientific knowledge. The change that this potential civilization will match our technological phase exactly has been calculated to be roughly one part in a hundred million.
As we continue exploring the cosmos, we hope to one day find evidence that our planet is not the only one in the entire universe where life came to be. If we do find evidence of alien life, this civilization will either be way behind or way ahead of our scientific knowledge. The change that this potential civilization will match our technological phase exactly has been calculated to be roughly one part in a hundred million. This means that we will either discover less developed civilizations, who have probably not even developed the ability of space flight or come across civilizations that are placed high on the Kardashev scale. The search for extraterrestrials is slow and painstaking. There are two ways we can come across evidence of alien civilizations. One is for us to explore distant alien worlds and look both for biosignatures and technosignatures.
Looking for alien civilizations
We will likely need to send autonomous spacecraft to distant solar systems to find life elsewhere. For example, Chemical rockets, which humans have used for space explorations for decades, are extremely slow. To arrive at our nearest star system, Alpha Centauri, some four light-years away, we would need to travel forty thousand years. Our chemical rockets are now traveling at a speed that is ten thousand times slower than the speed of light.
But there is another way to find traces of alien life. If life came into existence billions of years ago in the universe, then these civilizations would have significantly developed their technology if they have survived all this time. To find them, we need not travel to their star systems. Their technology has probably made its way to our very own cosmic background by now. This can be in the form of interstellar artifacts. And to find these objects, we need to look towards interstellar archaeology, a science that will significantly help humankind search for extraterrestrial life.