PostHeaderIcon Aliens? Yes. UFOs? No.

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!

Creating Life:

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.

Something More:

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?

Check out what Phil has said about SETI and about UFOs:

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.

10 Responses to “Aliens? Yes. UFOs? No.”

  • Howard says:

    Hi Alice,
    Fascinating subject. The universe is so big that there must be some intelligent life out there besides ourselves. I always think that when I look at a galaxy there is someone looking back.

  • Keith says:

    A couple of comments.

    1. “Carbon is Lego, Helium is Unifix Cubes”. I think Hydrogen would be a better analogy with Unifix Cubes. Neither H or He can form chains like Unifix cubes, but H can form one bond.

    2. “Protection from contamination”? I’ve never seen that listed as the “something more” that life has.

    The common candidates for the “something more” (the definining characterstic of life) include: the ability to grow and reproduce, the ability to use energy or metabolize, high complexity, and the ability to respond, adapt, or evolve. Personally, I don’t think reproduction is the only key, because crystals grow and reproduce. I don’t think using energy is the only key, because chemicals can use energy. I don’t think complexity is the only key, because machines are complex. I like the definition “life is matter that is capable of evolution” (I mean Darwinian evolution, not merely change). The word evolution implies a rich set of other cabilitities like growth, reproduction, metabolization, complexity, and adaptation. Every known living thing evolves and no known non-living thing evolves. (I’m not counting computer simulations as real things.) Without evolution, there would be no living things.


  • alicesastroinfo says:

    Howard – Thanks!

    Keith –

    I chose Helium, because like Unifix cubes it can make two bonds, even if it doesn’t make chains. Carbon makes chains, but it also does more. Hydrogen ends things.

    The “something more” section isn’t meant to be a definition of life. It’s meant to be the “spark” that we can’t cause to happen artificially yet. I was reading some stuff by scientists attempting to artificially create life, and one of the things they’re missing is a way to protect their artificial genetic code.

  • Jim Magee says:

    As long as you have it all figured out “scientifically” I guess there’s no need for concern. After all, how could thousands of credible witnesses (Stanton T. Friedman – for one) be right? They should have confirred with you, before issuing their statements. I always enjoy watching you earth people “scientifically explain away” the existence of UFO’s etc. It’s absolutely beautiful.

  • Alan French says:

    I started out believing there must be something to all the UFO reports back in the late 1960s and early 1970s. I read all the books I could find, and somehow the evidence I needed wasn’t there. C pevisited the idea about a decade ago when I went to hear Stanton Friedman. He didn’t provide any evidence either. Although he complained that skeptics often resorted to name calling, he spent a lot of time verbally assaulting people who didn’t agree with him.

    There are two basic problems with most of the people trying to convince us UFOs are alien visitors. The first is they can never say, “Oops, we were wrong about this case, so we’ll toss it out.” Second, they often embrace many even less believable ideas, making their judgment very suspect.

    Clear skies, Alan

  • astrogeek says:


    Very nice summary of the current state of knowlege. BTW, I’m adding you to my blogroll. :-)

    @Jim Magee;

    The claim of aliens visiting us in spaceships is extraordinary. As such it requires extraordinary evidence. To date, all evidence for alien spacecraft is anecdotal, and subjective.

    I’m not above believing we have visitors from ‘out there’, but I require quite a bit more hard evidence than has been shown so far… which is essentially zero.

  • Kevin Hales says:

    100 deg C is the limit at 1 atm pressure. Have the biochemists ruled out the possibility of useful reactions at high temp/high pressure? It seems the range of planetary candidates might be even wider.

    I wonder if, by the time we know enough about physics to build real starships, we will have found other aspects of “reality” that are more interesting that traveling thru 4-D spacetime to go visit another chunk of rock? In other words, anyone sufficiently advanced to visit other worlds would find the activity boring.

  • alicesastroinfo says:


    Oh yeah! I forgot to think about that. I’m certain the biochemists are thinking about this more than I am, and I’m sure they have more detailed and wider parameters than I do.

    Also, I like your idea about what will hold our (or others’) interest when we learn more. I mean, when we were living in caves what was interesting? Food sources? Yeah. Heat? I’ll bet. Space travel? Somehow, I doubt it.

  • Invader Xan says:

    What an excellent article! Do you mind if I add a footnote…?

    Regarding the elements that could form life, it’s worth mentioning that there are a couple of outside bets. Sulfur has an extensive chemistry and (at least in our solar system) is quite abundant in places. It also has a comparable electronegativity and atomic radius to carbon.

    What’s more, several (carbon-based) life forms on Earth have biochemistries centred largely around sulfur (for instance, “purple sulfur bacteria”).

    The only reason I’ve ever seen used to dismiss a hypothetical sulfur biochemistry is that it’s “too reactive”. As any good chemist will tell you however, reactivity is relative.

  • JMan says:

    I always find it interesting that anything to do with ET lifeforms assumes that the lifeform is something akin to ourselves in structure – even if it is slightly more like a frog with enlarged human head and eyes. We anthropomorphise, we can’t help it.

    If you were to project human technology 100 years into the future, given our exponential rate of increase in that field of endeavour, we would maybe start seeing the possibility of ET’s visitations as being something far beyond the architypal UFO (as a ‘spaceship’). Anyone (with a bit of imagination) who is following current research into the possible uses of quantum mechanics might think that this is far too simplified, and that ET lifeforms would, could and might know of our existance in a way that outdates our primitive radio signals, or a personal visitation via silver ships in the night.

    I’m a horrid ‘fence-sitter’ on this subject, and i do believe in both the possibilities and limitations of human scientific endeavour. But i do think it’s possible that “it’s life, Captain, but not as we know it…” ;)

Follow AlicesAstroInfo with RSS
Meet me on social media:
Follow AlicesAstroInfo on Twitter Follow AlicesAstroInfo on Facebook Follow AlicesAstroInfo on Instagram
Follow AlicesAstroInfo on TikTok Follow AlicesAstroInfo on Mastodon Follow AlicesAstroInfo on Tumblr
November 2022: I'm only really active on the bird app, but these other are me for real, and I'll switch when we need to.
Star Parties Nearby!