Geckzilla wrote:
I know there are a lot of brilliant people out there doing their damnedest to brainstorm and come up with ways to find life out there.
I don't think they are really trying to find life out there. I think they are coming up with ways to argue that there could be life in places where they know that there most likely isn't.
I have a book from the nineties at home, a book written at a time when it had just become possible to detect planets, and one astronomer quoted in that book speculates that it will be possible to distinguish between planets and brown dwarfs by looking at their orbits, because planets will follow circular orbits and brown dwarfs elliptical ones. So planets in other solar systems will be just like the dominant planets in our solar system, in other words. And because most other solar systems were thought to be like ours, they could also be assumed to have life-bearing planets.
It turned out that very many planets in other systems aren't following circular orbits. I realize why the astronomer fomulated his hypothesis, though. It's because planets are supposed to form out of the disk that feeds material onto the star, and that disk can be assumed to "orbit" the new star rather regularly. That's how astronomers reasoned in the 1990s, anyway. Brown dwarfs, however, were assumed to form independently from their own gas cloud, and afterwards they were thought to be captured by a larger star. That scenario would certainly be more likely to produce elliptical orbits.
Well, it turned out that the "planets follow circular orbits" hypothesis was just so much wishful thinking. And I think that the new hypothesis, the one saying that 77 out of 79 "hot Jupiter systems"
could host lifebearing planets, is also mostly a wishful thinking product.
Think about it. What do we know about those other solar systems that we have detected? What do we know about their planets? Frankly we know so extremely little about them apart from their masses and their orbits. What we know about their masses isn't all that interesting, because the kind of equipment we have got is really only good for detecting large and massive planets, so the fact that we haven't found any Earth-mass, Earth-size planets so far is a pure selection effect. The way I see it, we have no reason whatsoever to doubt that Earth-mass, Earth-size planets exist out there in large numbers.
But what about orbits? Is that also a selection effect? I doubt it. I believe the orbits we have found may be typical of orbits in other solar systems, also those containing Earth-mass planets. Well, the hot jupiters may not be typical, because they are extremely easy to detect, so we may well have seen them because they are easy to spot, not because they are common. They may in fact be rare. But what about the elliptical orbits? Are they also rare? I don't think so myself. I think they are typical.
Anyway, this is my point. Astronomers look at 79 systems where the only thing we really know, the orbit of the dominant planet, is absolutely nothing like the orbits of Jupiter and Saturn in our own solar system. They look at 79 systems where the
one factor we know about them makes them completely unlike our own system. Then they come up with computer models saying that 77 of these systems may contain a living planet just like our own. Is that serious science? Does it tell us anything about what those 77 systems are really like? No, the way I see it, it is mostly an attempt to make other solar systems seem like our own. Therefore it is mostly wishful thinking. If the stronomers really wanted to say something meaningful about those other planets, I think they should try to find out how likely it is for a hot jupiter system to have an Earth-mass planet following a circular orbit inside that solar system's habitable zone. But such calculations may produce depressingly low probabilities, so they seize on the fact that the probabilities they have come up with are not zero.
So I frankly don't think they are trying to detect life that way, I think they are grasping at straws and indulging in wishful thinking.