I’m a radio show host, and for an April Fools gag this year we pretended that a strange object had been spotted in the sky above a nearby town. We played it as skeptics who were gradually convinced, and we fooled some people. But that pretty much describes my real state of mind. I’d kind of like to be convinced that spacecraft from another place or time have come to this Earth, but for now I’m not. Here’s why.

If we propose that authentic Unidentified Flying Objects are spacecraft from some other solar system, the obvious barrier to that is Einstein’s assurance that nothing can travel faster than the speed of light. Millions of science fiction fans, including countless physicists and engineers, would really love for that to be proven wrong, but so far there’s absolutely no indication that it will be. However, even if we assume that advanced species may have solved the light speed barrier or found some other means of taking shortcuts through the galaxy (like stable wormholes), it’s still a big step to conclude that they have come to Earth. Yes, there have been many thousands of sightings of (so far) unexplained phenomena, but think about that. Is it really possible that our planet could have been visited that many times without the aliens just coming right out and saying, “Here we are” for the whole world to see? Without them making legitimate contact with us as a planetary species? If they have the technology to travel the stars and they’ve been coming here for the better part of a century, maybe much longer, they won’t be stopped by language barriers, they’ll know about our systems of government (the good and the bad), and they’ll know the best ways to reach individual humans in large numbers.

But they haven’t.

Yes, I know about the Prime Directive of non-interference. And look how many times Captain Kirk has thrown that one out the window. Are you going to tell me that not a single alien spaceship captain would have given in to that temptation over decades of time and thousands of visits? Oh, but it’s not just one species that’s come here, you say—there may be forty different kinds. Even less likely, then, that all of these various species would have the complete commitment and single-mindedness to have kept their presence a secret all this time. Why would they? We’re big boys and girls now—we can understand the concepts of alien biology and advanced technology.

The idea that governments have known about these visitors but kept the information from us is even sillier. Governments are leakier than soup strainers. Secrets that political administrations have the most powerful interest in preserving—their own misdeeds—rarely last as long as the governments themselves. Top secret technology is constantly being stolen, the most secure of databases hacked. Yet there are hidden desert bases housing crashed alien spacecraft, and mysterious government agencies to deal with them? I don’t think so.

In many ways it would be nice to be proven wrong. An alien species might have solutions to our very worst problems, like cancer, climate change, and nuclear proliferation. They might have answers to the deep scientific and philosophical questions that have puzzled us for millennia. And best of all, if they can cross galactic distances, then there’s no reason we can’t too.

For now, though, I’ll keep my skeptic’s hat on. But don’t worry, my door will be open if ET ever comes by and needs to borrow a phone