Any visitor who comes here from outer space is likely to be here for highly scientific research. It would require tremendous resources to get here and they are going to observe without interacting so they can project the earth's evolutionary future. That's how they determine if the dominent species will eventually become a threat to them. They age in years approximately the amount we age in minutes so they can document several generations of humans. They probably don't see us as a threat because we age too fast for space travel. But, will we destroy ourselves???