This is one of those that I find really cool but still can't help thinking, "What the heck?" about.
I don't remember what book I was reading when I first came across the term xenobiology. It was definitely science fiction, and, although I want to say it was Asimov, it probably wasn't. One thing I am sure about, though, is that it was not The Star Beast by Robert Heinlein, since I haven't read that. That is, however, where the term originates. At the time, it meant "the study of alien life." Even before coming across the term in whatever book it was, there was some other book that several different friends had back in the '70s that was a book of art of what alien life might look like. I was kind of fascinated with the book, especially since it was presented rather as if it was "true." The one image that has stuck in my mind (and I could not find the illustration) was of a large jellyfish-like creature that lived in the atmosphere of Jupiter (evidently inspired because Carl Sagan said something like that might possibly exist).
Several years after Heinlein's 1954 book, NASA started an exobiology program which focused on the search for life on other planets. Now, these were two different things:
1. xenobiology -- the study of "alien" life
2. exobiology -- the search for alien life
All of this came to be under the heading of astrobiology, which is sort of all-encompassing: Astrobiology is the search for extraterrestrial life and the study of its origin, evolution, and distribution (as in whether it's traveled from one planet to another (like on a meteor)).
But let's go back to just xenobiology for a moment. The idea of alien life is fascinating. And the movies of the '70s, like Star Wars and Close Encounters and, even, E.T. (yes, I know that one was 1980), really cemented the idea into the heads of many young minds. So much so that a "real" disciple around xenobiology developed. Mostly, it was involved in speculation about what alien life could be like, but they considered it a science. A completely hypothetical science. Which I just find fascinating. And astounding. I mean, I was completely unable to believe that there were schools that offered classes in this when I was still in high school and looking over my college options.
"Yes, please, can I sign up for that class in completely make-believe science?"
Not that I don't believe in the possibility of alien life; I do. I also find it completely... well, a little like jumping the gun to be trying to say that speculation about what life might be like on another planet is science.
Some good came of all of this, though. In 1977, we discovered some life here on Earth that does not require sunlight to live or, even, thrive. This changed our definition of the requirements for life (and I remember learning in science when I was a kid that sunlight was required). We've got the requirements boiled down to water and energy (pardon the pun), at this point. We don't even think that all life need be carbon-based anymore, which is another of those things I learned when I was a kid.
At any rate, all of this lead to a change in the definition of xenobiology to "biology based on a foreign chemistry." Mostly, now, it deals with weird forms of life we've been discovering on Earth that have previously been thought to be impossible (like the tube worms that don't need sunlight and those weird bacteria discovered a few years ago that can live off of arsenic).
But, still, there are plenty of people out there studying (speculating about) alien life that we haven't even discovered.
And, now, I want to digress for a moment (like that's unusual):
My buddy, Briane Pagel over at The Best of Everything is doing alien languages for the A to Z challenge. Well, saying that he's talking about alien languages might not be exactly correct since a lot of what he does is talk about talking about them, but that's his announced theme, so I'm just sort of going with it. Anyway... Last week he did a post about our potential for communicating with aliens if/when we ever do meet them. In his post, he talks about dolphins and about how we've been working with them for decades, and we still can't communicate with them. This seems like a similar topic to me as what I'm talking about with this xenobiology stuff.
People start talking about talking to aliens, and we haven't even met them. The pre-supposition is that they will be similar enough to us that we will have some basis of relation to them and, thus, facilitate understanding. And this might be true. However, it might also be totally wrong. Which is kind of why it's not the smartest thing to start speculating about these sorts of things. Talking to aliens or what alien life might be like.
Here's the thing, dolphins are smart. Really smart. Potentially, as smart as humans (or even smarter). After all, their brain/mass ratio is roughly equivalent to that of humans, which plays a part in our standards for intelligence. For instance, an elephant also has a brain that is roughly the same size as a human's or a dolphin's, but their mass is so much larger, they fall lower on the intelligence scale, because their brain has to be more concerned with their bodies than a human's brain to theirs. No, I don't know why it's defined this way, but that's how they do it. Well, okay, I do sort of know why, but it's not really important to this, so I'm not going to go into it.
So we have this animal that lives here on Earth with us, an animal that has a completely alien way of being. Alien to us, you understand. And despite that we've been working with them for decades, we're no closer to understanding how they communicate. And it's clear that they do communicate. But they don't communicate in any way that makes sense to us, but we think we'll be able to talk with aliens should we meet them?
Here's what I'm getting at: It seems to me that it would be more profitable for scientists to be spending their time on understanding the things in front of us that we don't understand rather than speculating about how we can send coded messages into space to talk to aliens. It seems quite clear to me that if we can't figure out how to communicate with dolphins that we have no hope of stumbling blindly across some code that will allow us to speak to aliens. And I give Briane the credit for this thought, because I'd never really thought about it at all until he brought it up.
In the same way, I think scientists would be better served working to understand the life on our own planet rather than speculating about how life might develop on some other planet. Until we can actually go there and see how that life might have developed, speculation doesn't matter at all. Not that we shouldn't look for life, I'm all for that, but the fact that we have (or had) a science devoted to studying alien life seems more than a bit like putting the cart before the horse.
Leave that stuff to the science fiction writers and you scientists get back to work on the real science. Like faster than light travel so that we can find that alien life.