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Milky Way Inhospitable?
tdfunk writes "Space.com reports that life in the universe may be more rare than previously thought.
In an article published today, Space.com quotes Guillermo Gonzalez, an Iowa State University researcher, who has studied the structure of our galaxy and has concluded that life may not be as common as we may have believed. Apparently, conditions around the Milky Way Galaxy are generally less hospitable than once thought.
No wonder all the UFOs and Aliens come to Earth, their looking for a place to live and no where else will do.
99.9999% or more of it is empty space, a near vacuum. What do we pay these scientists for again? :)
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Still, remember how many galaxies there were in some of the Hubble Photos? Even if the number of inhabitable planets/galaxy is low, there are still a lot of galaxies out there.
What if there were life forms on the sun? Or in the milky way. Maybe we, or anything else on earth could not exist in those regions but who's to say something else can't?
Scientists were suprised when they found life in the hot vents on the sea floor because they thought it was too hot for anything to survive there, yet there was something there. Humans couldn't survive there, but we were never designed to live there. If an organism was native there they would be formed in such a way to be able to withstand what it takes to live there. If they tried to come here maybe they'd die immediatly from something that makes the earth inhospitable to them.
Also organisms can adapt, and they might be able to adapt way beyond what we have witnessed thus far.
We may, it turns out, be very lucky to be here.
Luck had nothing to do with it, in fact, if you are an intelligent life form, there is a 100% chance you were born on a planet that is capable of supporting intelligent life!
And besides, suppose there is one planet capable of supporting life per galaxy, taking this researchers findings to the extreme. It is believed there are billions of galaxies. Billions of planets full of life doesn't sound too "alone" to me.
I've had enough abrasive sigs. Kittens are cute and fuzzy.
Guillermo is well known for the "Rare Earth" hypothesis, which boils down to the thesis that planets identical to Earth are extremely uncommon. This has even been covered on Slashdot before.
;-) is that time is so much longer than we humans can perceive. Humans have been around in our present form for only a few thousand years, with only a couple of decades when we could be detected by extra terrestrial civilisations. In terms of the age of the Earth that is nothing, and compared to the age of the galaxy it is smaller than nothing. Our window in time is so narrow that it seems unlikely that it actually overlaps with other civilizations.
I don't entirely disagree with Guillermo, but he does make one major blunder, IMHO: He assumes that complex life can only develop on planets with all of the same characteristics as Earth. That sub-hypothesis is not proven.
Regardless, lets say that a exact Earth analogs occur around one out of a billion stars. That still leaves 100 Earth analogs in the Milky Way alone.
The real issue for finding ET, IMHO (that sure gets tossed out a lot when discussing life in the Universe
A well-crafted lie appears unquestionable - Dama Mahaleo
The rationale for there being life elsewhere in the universe often goes like this:
1. There's life here
2. Well, we seem pretty normal and possible to me!
3. The universe is a many-splendored thing. There must be other neat planets like this out there.
4. Since we seen pretty easy to please, there must be life on those other planets!
People don't realize that it actually works the other way around. If there was going to be intelligent life just one place, well, wherever it was would have the intelligent life! To rephrase: just because we're intelligent and here doesn't mean that there are other intelligent beings elsewhere. That we're intelligent and here means that we've got good conditions for that, here. We (the intelligent life) are here and not on another planet because this planet is uniquely suited to us. About the other potential places that could harbor life-- well, who knows? The universe may be inhospitable. It may be hospitable. The fact of the matter is that we've just managed to find out whether one of our nearest neighbors has water on it. What do we know of the rest of the galaxy, really?
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... until we went there. The quality of your presumptions weigh heavily in the strength of your hypotheses...
"I said that "D" that is probability of life on planet is nearly ZERO"
Question: Do you mean intelligent life like human beings, or are you including microbes, bacteria, and so on?
In the case of Human-esque 'intelligent' life, I agree that the scale of time indicates low probabilities of life existing within our own life time. (I mean human kind, not me and you...)
In the case of bacteria and so on, I find it unlikely that the Sol system is one of very few occupied planets. There's evidence that life can exist anywhere it is inclined to.
But you know, if you think about it, what good is probability? What are the odds of me arriving home safely tonight between 6:15 pm and 6:20 pm? Well, first there are a number of intersections I have to cross. Then there's the factor of me leaving the office at the right time. Somebody might want a last minute change. There's the factor of my speed, which is a little inconsistent since it is raining today.
If you sum up all of the various factors, the odds of me arriving home between 6:15 and 6:20 today are heavily against my favor. Yet, if I work at it, I'll manage it.
I'm not saying you're wrong about the possibility of life, I'm simply stating that probability doesn't affect outcome. If life exists, it's already out there. In this case, it's just a matter of finding it, not proving it does or doesn't exist.
I do agree with you, though, that we have needs ahead of looking for ET life. But I don't agree that SETI should be shut down. The benefits of SETI have already been worthwhile, like the massive supercomputer they created with the internet to process their data.
"Derp de derp."
Why does everybody always assume that life can only form in conditions that are hospitable to humans?
Who's to say that there aren't other strange forms of life that have evolved to survive in conditions that would be downright hostile to humans?
Economist #1: "The economy is going to collapse this quarter!"
Economist #2: "No! It's on an upswing, you idiot!"
Dietician #1: "Balanced intake of carbs, protein, and fats is best."
Dietician #2: "Uh, yeah, sure.. if you want to look like Rosanne. Max protein, don't worry about the fat, and cut down on the carbs."
Space Scientist #1: "Thousands of life-giving planets are out there. We have the calculations right here. Really."
Space Scientist #2: "Look, dude, the odds of there being other life-bearing planets are almost nil. We have the calculations right here. Really."
I mean it in good humor, but as a layman it sure is difficult to tell which of the astronomers and other guessers are on the right track.
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A Milky Way is quite hospitable. Leave one on your back porch. It'll be teeming with ant life pretty darn quick.
--
"Outlook not so good." That magic 8-ball knows everything! I'll ask about Exchange Server next.
Multicellular life is a whole different story. It's a lot more delicate, and in our planet's geological history, it appears as an afterthought. Germs are and always have been the dominant form of life here.
Sorry if you're in love with the Star Trek/Star Wars picture, but most likely if our species ever manages to send probes to the nearest 10,000 solar systems, all we'll find is unicellular life. I'll bet your great-great-great-great-great grandkids a six-pack on it!
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I was recently reading up some more on gamma ray bursters, which are a recently discovered thing with explosions (so far only seen a very long way away) that appear to have an amount of energy equivalent to about the rest of the Universe put together.
There was a paper published in 1999 that theoriesed that every gamma ray burst was a galactic scale mass extinction event, and then attempted to extrapolate a rate that they occur locally in the Milky Way, then going on to suggest that because the rate is slowing down, we might be in a transition period for intelligent life appearing. It's all entirely theoretical, but it's an interesting read.
The good news is "at last we're here". The unfortunate bad news if the theory is correct is that because the last burst is somewhat overdue, we might not be here for much longer.
For what it's worth, there's a hugely massive star (eta carinae) about 7,000 to 10,000 light years away that's arguably ready to blow some time in the next million years. (If you're in the southern hemisphere it's a really nice thing to look at with binocs or better.) It's on the fringes of the theoretical limits of how massive a star can be, it's gone past the theoretical limits of the maximum amount of light that a star can possibly emit, and it's been suggested as a possible source of a future gamma ray burst in the Milky Way. Really though, nobody's quite sure what's about to happen. On the other hand we should probably be hoping that we're not nearby when it decides to go.
It's just another theory.
Doesn't that assume that the life forms will be something like us? Terry Bisson has a great perspective on this from his short story/play "They're Made Out of Meat":
"They use the radio waves to talk, but the signals don't come from them. The signals come from machines."
"So who made the machines? That's who we want to contact."
"They made the machines. That's what I'm trying to tell you. Meat made the machines."
"That's ridiculous. How can meat make a machine? You're asking me to believe in sentient meat."
"I'm not asking you, I'm telling you. These creatures are the only sentient race in the sector and they're made out of meat."
"Maybe they're like the Orfolei. You know, a carbon-based intelligence that goes through a meat stage."
"Nope. They're born meat and they die meat. We studied them for several of their life spans, which didn't take too long. Do you have any idea the life span of meat?"
"Spare me. Okay, maybe they're only part meat. You know, like the Weddilei. A meat head with an electron plasma brain inside."
"Nope. We thought of that, since they do have meat heads like the Weddilei. But I told you, we probed them. They're meat all the way through."
"No brain?"
"Oh, there is a brain all right. It's just that the brain is made out of meat!"
"So... what does the thinking?"
"You're not understanding, are you? The brain does the thinking. The meat."
"Thinking meat! You're asking me to believe in thinking meat!"
"Yes, thinking meat! Conscious meat! Loving meat. Dreaming meat. The meat is the whole deal! Are you getting the picture?"
"Omigod. You're serious then. They're made out of meat."
"Finally, Yes. They are indeed made out meat. And they've been trying to get in touch with us for almost a hundred of their years."
Read the rest here (it's very short).
I haven't read any comments that point out one of the severe flaws in the implied logic of the article. Specifically, that Gonzales assumes these characteristics necessarily preclude the frequent formation of earth-like planets. The fact is, however, that such a leap of logic is unjustified. Such a claim requires more detailed explanation of how each of the identified conditions would interact with an actual solar system, down to the climate of the affected planets. We are frequently surprised both in Astronomy and on Earth by the huge impact of seemingly subtle details. The fact that this article offers few (zero) details and utterly lacks careful explorations of the interactions Gonzalez mentions, suggests that his conclusions cannot be taken as more than vague musings.
It also strikes me that Gonzales may have decided what he wants to believe, and then went looking for justification. The only problem is, he didn't actually find that justification; he just found hints that he selectively presented to bolster his assumption. He says something to the effect of "the galaxy is a scary place, therefore Earth-like planets hardly ever form." That makes for an interesting conversation, but by itself is very far from convincing.
Until we understand in great detail how planet forming processes & external factors interact, or can exlicitly look for extrasolar Earth-like planets, we can't disprove these assertions. That doesn't,however, mean we should assume, as Gonzales would like us to, that nice planets necessarily can't be common.
There are, however, hints to believe Earth-like planets could be common. Distant solar systems are, for example, discovered regularly. Unfortunately we don't have the equipment to determine if classicly habitable planets exist in those solar systems. But if we assume the presence of solar systems indicates any likelihood of habitable planets, then there's a hint that habitable planets could be common. It's far from convincing, but no less so than the assertions in this article.
(As an aside, Gonzalez also ignores the possibility that there may be certain areas of space that make Earth-like planets significantly more likely to form. For example, maybe in some parts of the outer edges of the galaxy one or two Earth like planet are the norm in one-star solar systems. The point is, we don't know and can't fairly assume either way.)