Aliens Might Evolve Into Jabba The Hutt Covered In Anuses
The biggest assumption we make about aliens is that they'll look at least vaguely like us. Part of that is convenient shorthand; it would be hard to bond with a fictional alien if it had 27 ear-penis hybrids protruding from its giant slug body. But we also figure that we look like us, and we turned out OK, so clearly this is a good evolutionary route to take.
But that forces us to make a lot of other assumptions about the conditions of an alien planet and the chemical building blocks present there. If aliens exist, there's no guarantee that they're living on a planet exactly (or even vaguely) like ours. What is safe to assume is that aliens were subjected to the same laws of natural selection that we were. If you're not adequately built for the salt storms of Xipglor, then get the hell out of the Morplok.
Humans, if you'll forgive the casual existential horror, are just giant masses of cells working together. And human evolution had a few key stages when that work got more complicated. Single-celled organisms became multi-celled organisms, multi-celled organisms saw increasing numbers of parts performing an increasing number of functions in tandem, and eventually all of that cooperation produced Chad, your neighbor who insists that everyone in the African country shares his name. The process that produces that complexity is what we should be looking for in intelligent life, regardless of the resulting physical appearance. And that means real first contact might be Buzz Astronaut going for an uncertain hand-to-maggot-penis shake with the butthole cactus here:
Helen Cooper/Cambridge Univ. PressWe imagine Captain Kirk would've spread a lot less love between worlds if any of those green women had looked like this.
No, astrobiologists don't think that we'll specifically run into this creature that clearly wants to eat our genitals, but in the right conditions (namely, conditions that are quite different from our own), a bunch of smaller parts could come together to form something that's as complicated as us, despite looking nothing like us. Life doesn't inherently create human-like creatures -- it just creates. And if we ever do run into something along the lines of what's been dubbed the "Octomite," we'll have to make sure we don't show them all of our television shows, in which our noble heroes immediately destroy anything that looks remotely like that.
Alien Life Could Be Silicon- Or Methane-Based
Humanity, along with all other life on Earth, is carbon-based. Carbon is great at bonding and forming long molecular chains, and it's often been assumed that carbon is a requirement for metabolism and other important functions that make life work. But "carbon chauvinism" has been disputed more and more over the years, which we're sure has led to some sarcastic comments about Silicon Justice Warriors.
Silicon is generally thought of as the most probable carbon alternative. It's commonly found throughout the known Universe, it's good at bonding, and it's easy to manipulate in a laboratory setting. It does have some downsides, but it's so easy to coax silicon into various artificial molecules that it's reasonable to assume that it's happening naturally somewhere in the Universe. But whether we'll actually stumble across that happening is another issue, so let's look at a different carbon alternative that could be hanging out close to home.
James Stevenson/CornellThankfully one whose ability to rectal-probe seems limited.