And the ancient Roman Empire and the ancient Chinese Empire were immense, powerful and had great influence in those parts of the world where located. It's hard to believe, given the vast distances, the ocean and the lack of means of communication, but most likely, the Empire knew of each other's existence. At least, China was definitely aware of the Roman Empire.
The Chinese called the Roman Empire Daqing. They felt that some of it is in what is now Syria. Perhaps the ancient Chinese learned about the Romans, as the boundaries of the Empire took place near the famous Silk Road. China mainly led trade on the one end of the road and thought that Daqing is located somewhere on the other end.
The 97-year district. e. General Ban Chao sent to the Roman Empire as an ambassador Gan Ying, one of the soldiers of the Chinese army. However, when Gan Ying reached the so-called "Western Sea", I could not cross it. Some sources have information that he did not even try to do so as a sea voyage would be too dangerous and would take a long time. Although Gan Ying wrote about the Roman emperor in his travel notes, most of the messages were not confirmed anything, and in fact were simply speculation.
Knowing this fact, it is impossible to refrain from making an analogy: perhaps somewhere on the other end of our universe there is a developed civilization, just as we are assuming that somewhere there are other worlds inhabited by intelligent beings. But the opportunity to communicate with each other we do not have, simply because modern technology is not allow.