Well, scientists have the trust of the people (the majority anyway), if a scientist or group of scientists (well known) claimed that God was found, do you think that people would believe it ? (Be reasonable AND meaningful)
Not at all. I think you've interpreted this incorrectly. The term Alien doesn't only mean those things with the oval head and big gloomy eyes, it means other life-form (simply, anyway). It doesn't disprove the existence of God, it's a fabrication to represent God. More importantly, words are...