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.

Comments

On a more serious note

[GigsVT]

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.

Old news...

[Boulder Geek]

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.

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 ;-) 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.

Re:Old news...

[Daniel Dvorkin]

Guillermo Gonzalez is also well known as a proponent of "Intelligent Design," the pseudoscientific creationist idea that An Intelligent Designer (read "God") must have made our universe because everything in it is so perfect for human life. (Do a Google search on "Guillermo Gonzalez intelligent design" if you don't believe me.) It's not surprising that ID and Rare Earth-ism go hand in hand; if intelligent life is common in the universe, it makes it less likely that humanity is the product of a Divine Plan -- at least to the degree that the limited minds of ID'ers and other creationists seem to be able to conceive divinity.

Re:Old news...

[IamLarryboy]

It has been my experience that creationists such as Guillermo Gonzalez can be divided into 3 catagories.

1) Those that do not know any better. These people believe that God created the earth and everything on it in 6 days because that is what they have always been taught. They are largely ignorant and have no real interest in looking into the facts. These people can be found in almost any church.

2) Those that believe that God created the earth in 6 days because that is what the bible says and that is good enough for them. These people are completely unwilling to even consider even the consider the possibility that they are wrong. Often they ignore sound science and instead rely on sudo science to try and convince otherse and themselves that they are right and everyone else is wrong. They ignore all contradictory evidence and are as unscientific as can be. Thse people do both thier faith and their theories a disservice. These people can also be found in most any church and are very vocal. Often people beleive that this group are the only proponants of Intelegent design or creationism. An example of this group can be found at www.icr.org

3) Those that beleive that God created the earth and all life on earth but not neccisarily in 6 days(as we would know them). These people "assume" (they do not really assume rather these they rely on these "assumptions" based on other evidence and experiences) that both the scientific record and the bible are 100% correct. Therefore, there should be complete agreement between the two. If there is an aparent disagrement either the scientific record has been interpreted wrong OR the bible has been misinterpreted or mis translated. This group is generally willing to examine its theories for weakness and to modify its theories to better fit the available facts. This group is as scientific as any evolutionist group and if more creationists were like them perhaps they would not be seen in such a bad light. Unfortunalty, this group is rather small but growing. An example of this group can be found at reasons.org

Likewise, evolutionists generally fall into one of three parallel groups.

1) Those that do not know any better. These people believe that man evolved by natural processes because that is what they have always been taught. They are largely ignorant and have no real interest in looking into the facts. These people can be found almost anywhere.

2) Those that belieleve in evolution because they are unwilling to consider even looking at any evidence that perhaps there is a god. They would rather blindly believe a theory with known problems than consider an alternative. They have evolution taught in schools as fact even though it is only a theory. They do not want children to be taught that some people do not agree with evolution. These people do both their "religion" (atheism/naturalism) and their theory a disservice. These people are very vocal and are just as unsientific as a creationist in group 2. They also can be found most anywhere.

3) Those that believe in evolution (or some other naturalist theory) because they genuinly believe that it fits the facts. They are willing to look at alternative theories. They are also examine their theories for weekness and are willing to modify their theories to better fit the known facts. These people can be found inside the bona fide scientific community.

It is a shame that there are so many group 1 & 2 people in this world.

In conclusion, no theory is pseudoscientific. It only becomes sudoscience once it is conclusivly disproven yet is still passed off as scientific fact.

The same was said of the bottom of the oceans

[DrMegaVolt]

... until we went there. The quality of your presumptions weigh heavily in the strength of your hypotheses...

less hospitable to HUMANS

[jimmcq]

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?

Re:less hospitable to HUMANS

[barawn]

Because if you think about it, the life that we have (as humans) is, in many ways, analagous to a "minimum-energy solution" to a problem.

Think about it. Life on Earth begins, fundamentally, with long carbon chains and water cycles. Why carbon? Carbon is the only element that can form arbitrarily long, stable chains. Silicon can form chains - but only short ones. Longer silicon chains break down. There are additional reasons for carbon later, too. Why water? Take a list of molecules, starting from the simplest you can make. That is, H2, LiH, etc. Many of these compounds won't exist, though. Keep going. Water will stick out like a sore thumb when you get to it - because it's the first strong dipole you'll come across that's covalently bonded. The covalence is important because in a liquid form, the molecules are still there, rather than just ions. Ammonia (NH3) is a dipole, but not of the same level as water is. So, a water solution provides literally TONS of bonding possibilities. Hydrogen bonds form all over the place, and you get extremely complex chemicals popping up everywhere.

The basic requirements for life, in my opinion, would have to be the possibility for many, many combinations of molecules. That's what allows life to exist, really. So carbon/water based life suddenly becomes your 'minimum-energy' solution to generating life.

The other reasoning here is that if you look at the basic life on Earth, the elements it uses are, well, a little bit "unique" on a stellar scale. The most important elements for life on Earth are undeniably carbon, hydrogen, nitrogen, and oxygen. Without a doubt, you could probably make living objects from just these few elements (probably really basic, but still life). Here's the kicker: hydrogen is the most abundant element in the Universe, and carbon, nitrogen, and oxygen are the elements produced in the second most common stellar nucleosynthesis event, the triple-alpha process (the pp chain is the most common: it turns 4 protons into 1 alpha particle). So flat out, you are NOT going to have carbon somewhere and NOT have water, not for stellar abundance reasons. Temperature-wise, it's possible, so in very bizarre temperature regions, you might get life - I will admit that - but I do consider it unlikely, since high temperature regions don't really allow for molecules to form easily. :)

That being said, I want to note that I don't agree with the author here: I think he's being exceptionally restrictive. My opinion is all you really need for life is carbon and water. You probably also need nitrogen for variety, but as I've said, where there's carbon and water, you'll have nitrogen as well. Now, the 'livable for humans' bit: I honestly think that anyplace that has carbon, liquid water, and nitrogen could be made livable for humans. You need trace elements (iron, for instance, for hemoglobin), but in general humans recycle them - they don't get 'consumed' - so a well designed colony could probably survive by taking some small amount of trace elements along with them. But as for life developing THERE? I think with the above ingredients, they would find a solution that doesn't use a trace element that they don't have.

It doesn't matter, really. We have one data point to play with, and we can do whatever we want with it. His instinct says "no life anywhere, it's really complex" my instinct says "life everywhere there's water and carbon: it has this 'knack' for showing up everywhere."

What a crock

[sharkey]

A Milky Way is quite hospitable. Leave one on your back porch. It'll be teeming with ant life pretty darn quick.

a galaxy full of germs

[bcrowell]

Unfortunately, popular articles, including this one, don't usually do a good job of making the distinction between unicellular and multicellular life. There's every reason to believe that unicellular life is common in our galaxy. Microbes are tough. They can survive and/or permanently adapt to extremes of temperature and chemistry. It's quite possible that even within our solar system, there is unicellular on three different bodies: Earth, Mars, and Europa. When the "rare earth" folks talk about the dangers to life, such as ionizing radiation and comet strikes, those are really more like hazards to multicellular life. An unknown, but probably very big, percentage of the earth's biomass consists of microbes living deep underground or underwater, where they're relatively invulnerable to these things.

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!

Gamma ray bursts and the Milky Way

[jesterzog]

Space.com reports that life in the universe may be more rare than previously thought

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.

Re:How do we know what is hospitable?

[John Miles]

Adaptation comes after multicellular life.

There is absolutely no basis for that statement in reality. Although the researchers and doctors dealing with the evolution of drug-resistant bacteria would certainly prefer it that way...

So, so arrogant

[Comrade Pikachu]

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).