NEIL DEGRASSE TYSON: There are many people who see things in the sky and are sure – they can't explain it, so they're sure it's aliens visiting. Well, if you were really, really sure of that, you are not likely to write me a letter. Unless you're writing me a letter to convince me of your point of view. But that doesn't make for a fertile exchange. If you see lights in the sky and you don't know what they are and you want further insight on what they could be and write me a letter, that's a meaningful exchange.

If you can't explain what it is and it's flying and it's an object, it's an unidentified flying object, period. You just said you don't know what it is so that sentence should not continue beyond that phrase. You can't say I don't know what it is, therefore, it must be aliens visiting from another planet. If you don't know what it is it therefore must not be anything.

Okay, so maybe we are getting visited by aliens daily. In all of these sightings, it's aliens. I don't have a problem with that. My issue is what you are presenting as evidence in support of that claim. If it's entirely grounded in your eyewitness testimony you need to know that eyewitness testimony on the totem of weight of evidence it is at the bottom. A little scary because in the court of law it's considered pretty high evidence. People say, "I need a witness!" No, you want data. That's what you really want. You want information that didn't have to pass through someone's sensory system so that you can minimize bias, delusion, the filtering that we always do as the world outside of us comes through our senses for us to then decide what is and what is not going on around us. It's why we invented science. So that we wouldn't have to depend on our senses as the ultimate measure of what is or is not true in the world.

Science and its methods and tools. The telescope, the microscope, the recorders, chart recorders, all of this. So, the best thing is—and by the way, I don't care what your pedigree is. I don't care if you're a military colonel, pilot, Air Force. Are you human? That's all that matters. After that give me better evidence. And yes, Carl Sagan's famous dictum, "extraordinary claims require extraordinary evidence." So the best thing is to drag the alien into town square and you'll be rich and famous overnight. You don't have to argue with me. I'm not stopping you. Go ahead. But do you know what's more significant than that fact is that today, worldwide, we are uploading to the internet a billion photographs a day. Everyone has a camera and a video camera. Remember all those reports of people getting abducted and poking their gonads? Where's the video of that today? You can film that and stream it to the internet while it's happening in case they snatch it from you. Because these aliens they don't want a record of this of course.

Where's all the video? Where are the images of you posing for selfies with the aliens? I don't see that. That would be very helpful starter evidence that you're experience was real and don't require that I have to depend on your eyewitness testimony to decide what is or is not true in this world.

You know what would make good data? You're in the flying saucer or whatever it is they came here in. Tell them to "look over there!" and while they look away snatch something off the shelf like an ashtray or something. I don't know if the aliens smoke. Snatch something. Anything off an alien spaceship is going to be interesting. Anything. I promise. And then you've got something to bring to the lab if you can't drag the alien itself. Then we can talk. Until then spend more time getting better evidence than trying to convince people that they exist in the absence of it.