On the topic of aliens and UFOs, I agree with the giants of astronomy education (Carl Sagan, Neil DeGrasse Tyson, and Phil Plait to name a few). Somewhere out there is life. It may or may not be intelligent, but it probably exists. Have “they” visited us? The possibility is vanishingly small. In short: Space is huge, it would be amazing if the right combination of our 120+ known elements only came together to form life here on Earth and nowhere else.
I’m going out on a limb. I’m not trained in rhetoric, so I expect my discussion to have major loopholes. I invite readers knowledgeable about this topic and knowledgeable about rhetoric to comment, and help me close up those loopholes. I would also like to point out that I started writing this article on November 18th, 2008 (I’ve been struggling with it for a long time). Phil wrote his post of the same title on November 25th, 2008. Whether you believe me or not, I’m not copying him.
Finding a Place to Live:
When we talk about alien life, we talk about “life as we know it.” Life as we know it needs liquid water, which is between the temperatures of 0C and 100C. Our experience suggests that this occurs on planets and moons.
Have we found planets? Yup. We’ve got 322 (last I checked) planets orbiting other stars, and those were the ones that were EASY to detect. Those don’t tend to be in the right temperature zone, but if we’ve found 322 in just the last 5-10 years, imagine how many more there must be!
You need some complex molecules to create even a single-celled organism. Carbon is great for this, because it can easily make form four bonds to other elements. Imagine Legos (TM). You can build anything you want out of Legos(TM), even if all you have is the quintessesntial 8-stud brick, because you can attach pieces together in other ways than just a straight line. When I was in school we also had Unifix Cubes . They were so frustrating, because all you could do was make a long chain. You couldn’t build robots or houses or anything. Carbon is the Lego of the Universe, Helium is the Unifix Cubes. There aren’t many other elements that can be the Lego of the Universe. Silicon is one, but Silicon is significantly less common in the Universe than Carbon. One of my astronomy professors argues strongly against the possibility of Silicon-based life, but I’d like to leave the door open on that one: the Universe is a strange place.
We don’t know what it is, but there’s something else that you need to move from a gigantic mass of complex molecules to something “alive.” Is it protection from contamination? Is it the ability to take in and use energy? Scientists are working on this. (Here’s a much better article that reinforces the “moving energy around” idea as what got life going: Why Life Originated .The original link that caused me to say “protection from contamination” is here , though I don’t really like it much.)
So, the first two are easy. The third one we’re not sure about, but People Who Know think it’s a problem for us as humans to figure out, but not too difficult for Nature to stumble across. After all, Nature has a lot of space and a lot of materials, all combining in different ways all the time.
Once you’ve got life, you need to evolve into something intelligent. Then into something that can communicate – that took us millions of years. Then (if you want SETI to succeed) you’ve got to communicate across thousands, hundreds of thousands of lightyears, and stay alive long enough to get a response (this is hard). If you want our UFOs to be of real alien origin then you ALSO need to become spacefaring, travel across thousands, hundreds of thousands of lightyears, (stay alive for that entire journey – which is SUPER-HARD), and arrive at Earth. Hmm.
Earth has only been broadcasting signals into space for 50-100 years. If they’re further than 100 lightyears away, how would they decide to come here? Before we started broadcasting we were nobody. If they’re closer than that, and they can detect radio transmissions, why haven’t we heard their radios? Or, if you want to believe in UFOs, how did they get here so fast? It violates our understanding of Physics, and it doesn’t add up. They do this in Star Trek with fictitious (and awesome) inventions like subspace and warp drive. In Star Wars and Babylon 5 they use hyperspace. In Stargate they use a portal. Fiction. All of them.
When we invent warp drive (real and for true) I’ll eat my words and grant you the possibility that the UFOs really are aliens. Till then, I’m going to say it’s probably the Goodyear Blimp, a bollide, or even a pretty planet.
Who Do You Trust?
Why are you listening to me? I’m not an expert in aliens (who is?). I’ve only seen one UFO in my life (it later became an IFO: the Goodyear Blimp). So then, if I’m not the expert, what did I base this article on?
With the breadth and depth of knowledge now available to the human race, one person can no longer “know everything,” nor can one person understand everything. We are not Erastothsenes, Aristotle, or Plato. We have to trust other people to tell us things. Because of this, we have to choose where we get our information carefully, and everyone will choose different sources as trustworthy.
Me? I trust Carl Sagan  and Phil Plait . I also tend to trust Neil DeGrasse Tyson , though I disagree with him on some points of quality education. I like to trust NPR, and I listen to everything Garrison Keillor  has to say. I don’t trust Wikipedia  to do anything other than jog my memory, point me towards a list of sources, or give me unimportant information (how old is Zac Efron? ). I get my tech news from Boing Boing , and my local news  and weather  from specific blogs (I choose blogs for local information because they know they’re fast, up-to-the-minute, they know they’re biased and admit their bias, and the writers can change their minds and edit things anytime). For current astronomy questions I ask my college profs, re-read my texts, look at the data, and wade through the peer-reviewed papers (if I have time).
Where Did I Get My Info?
Neil DeGrasse Tyson gave a great speech about this to Congress .
How many aliens are there? Figure out your best guess with the Drake Equation .