Tyche Shepherd

Since the International Astronomical Union defined one of the requirements to be a planet as having a primary orbit around a sun

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Hiro Queso

No there isn't. The method you are thinking of is spectroscopic analysis of the atmosphere. So far we have only been able to get a fingerprint of basic molecules on a couple of planets - the tech is still too basic. We need bigger space scopes before we are able to use spectroscopy to detect the chemical signatures of life on exoplanets.

Me thinks Michael needs to read my posts more carefully. The definition of 'rare' does not even enter the picture, as we don't have any data to make a statistical analysis.

We can't even directly detect planets that are similar to Earth; we don't have powerful enough scopes!

You need to get the data before you can make decisions about how rare something is. Duh.

Have a cookie.

Hiro Queso

How can you say something is rare in the absence of data?

That's like not allowing anyone to vote on the election and then stating that McCain should be president on the basis that there has been no votes for Obama/Clinton.

Malachi

No one knows how rare life is and there are many ways to guess but no good ways. Certainly the handful of probes that we've thrown out into our solar system are a pitiable attempt to find evidence of life. There are two things that make me believe that life isn't too hard to come by. The first is that we've got pretty decent evidence that life arose on earth at around the time the crust was cool enough for any complex molecules not to be instantly torn apart (age of earth ~ 4.5 billion years, oldest remaining evidence of life ~ 3.5 billion years). The second reason I have for believing life to not be uncommon is that using the definition of life of "self-replicating things" the Darwinian conditions for the evolution are few and simple:

1. A system of heritability (whereby the "child" of a replicator is more or less like the replicator itself)
2. differential rates of reproduction between different replicators
3. a causal relationship between features of the replicator and its rate of reproduction (something about the replicator makes it better or worse than its neighbors at making copies)

Now understand I'm talking pretty tiny molecules, indeed we've found 550 base strands of RNA that are capable of self-replication (and that's all they really can do). What is interesting to me about life on earth is that it spent a whoppingly long time (~2 billon years) as the simplest of the simple organisms that exist today. What was it doing all that time? Possibly refining the machinery of living, but we are certain that it was evolving because evolution happens willy-nilly so long as those 3 conditions hold.

Every living organism we see now seems descended from a single common ancestor because they all share the same fundamental molecular machinery. However, it is not clear that these were the only replicators that ever existed and they probably weren't. There's even some reason to believe that all life we see now literally formed on the backs of some earlier replicator. What we do know is that then as now, there was competition for resources and our oldest common ancestor probably drove all its neighbors extinct. Alas, much of this may remain at the good guess stage as much of the relevant evidence is long gone (although they do keep turning up older evidence, so who knows).

Incidentally, I've owed Cindy a reference for the degenerate self-replicators which I've just now remembered and may be of interest to readers here. It was Speigelman's work with Qβ replicase. (I didn't know his resume, pretty impressive guy.)

Michael Bigwig

Perhaps you're right. Technically, the moon *is* orbiting a star...

The moon is a 'planetoid.'

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While the moon is a large orbiting body, it is not technically considered a "planet". Planets orbit stars/suns.
Both moons and planets are satellites. The Moon is a satellite of the Earth. The Earth is a satellite of the the Sun.
Since Pluto has been demoted from a planet to a dwarf planet, we now have 8 planets in our solar system and 3 dwarf planets. Most planets have their own moon or set of moons.

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Of course, scientists were talking about changing the definition of planet at some point...



CNN.com - Earth's moon could become a planet - Aug 18, 2006

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~Michael Bigwig
___________________Lead Designer, Glowbox Designs

Beau Perkins

The same way I take insults for believing in a creator even though we have no "proof".

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Hiro Queso

The Moon is a moon. If the orbital focus of the Moon-Earth system lay between the two bodies (instead of within the Earth), they would be binary dwarf planets.

But it's all just semantics, and I can't believe the amount of time and energy scientists spent debating the status of Pluto!

Beau Perkins

Me to, how can they say he is a Dog? He doesnt even look like one.


Edit- Joke gone bad, I was thinking of Goofy.

Jessyanne

It's been known to happen

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Hiro Queso

What?

Beau, I am not insulted - I don't understand the analogy. I am merely pointing out that you can not state something is rare until you have the data upon which to make a statistical analysis.

Anyway, I feel like I am banging my head against a wall here (not directed at anyone in particular), so will exit the thread.

Michael Bigwig

Dude, you are impossible. You still claim life isn't 'rare'

Wow. Wow. And more wow.

Unbelievable. You get the cookie for being most stubborn of all time. The definition of rare very much comes into play...(edit: you say we 'don't have any statistical data to back up...) Wow...how much or little of the universe do we need to see before you agree life is rare? For fuck sake, twins are 'rare'...I'd certainly label life in the Universe rare.

Life in the Universe is rare...why can't you accept that?

Don Mill

What Hiro is trying to say is that if you have not yet been able to leave your cradle, any arguments to where there are people in the house is meaningless; much worse if you consider the neighborhood.

"Life is rare" depends on the size of the universe you are measuring against.

Hiro Queso

Im stubborn and impossible?



Michael, try reading my posts; it might help you understand.

I didn't say life is rare.
I didn't say life is ubiquitous.

I didn't say either of these because I do not have the data to make such a ridiculous statement. That doesn't stop you, of course.

Michael, I've pretty much had it with you now. I find conversing with you to be too frustrating. I'm sure that's no loss to you, but at least you know.

Love & Hugs.

Don Mill

The fallacy here Michael is that you are measuring life as you know it. You are considering carbon-based life-forms.

We have no idea whether any other type of life can or can not exist anywhere in the universe.

I guess you and Hiro are getting into a pissing contest over a concept that is meaningless

Cocoanut Koala

Pluto is a planet and that's all there is TO it!

coco

Don Mill

Prove it.

Michael Bigwig

hahah...read the definition of 'rare'

I did prove it. If you can't relate that, then someone is either being difficult on purpose, or not very good at literary analysis.

Cindy Claveau

Not exactly. Hiro's right, we don't have the technology to determine whether a planet orbiting a distant star has Life. All we can do is use spectrography to determine whether the conditions are "Earth-like" and MAY be agreeable to "life as we understand it".

But, there's the hitch. Paleozoic Earth didn't exactly have an atmosphere agreeable to humans. It was great for Permian plants and tetrapods, which also qualify as "life", but humans would probably have choked on the atmosphere.

We are acting on the assumption that sentient life will most likely be carbon-based and breathe oxygen, but only because that's the only dataset we have to work with. As these things go, eventually it's possible we'll run into life forms that are silicoid, methane-breathing or any of a number of other possibilities. But it's speculative to include those in the realm of possible environments just yet, before we have any evidence that it's possible.

Right here in our own solar system, we've found evidence of water ice on Europa and Mars, which is one of the fundamental requirements for our carbon-based life. We've even discovered microbes that actually eat rock and live far below the surface - how can you spot something like that from 10 light years away?

We estimate that there are roughly 100 BILLION stars in our galaxy alone, and there may be anywhere from 100 billion to 1,000 billion galaxies in the universe (the farther we can see, the more we find).

If one does the math, one can see that "rare" is not a useful term in this application - what may be "rare" by percentage could actually be extremely abundant in absolute terms. If even 1% of stars are conducive to life in our galaxy alone, that's 1 BILLION stars that could potentially support life. Even a fraction of that number is still mind-boggling, and once you expand your search to the entire universe, it becomes pretty obvious that the numbers of possible life-supporting systems are astronomical.

No pun intended.

Michael Bigwig

I think the 'fallacy' here is delusion. Maybe even purposeful difficulty. The answer is in the definition.

If you want to spin the concept of 'rare' to suit your own needs, you go right ahead. But I don't know a scientist (or reasonably intelligent human) that wouldn't agree to the idea that life in the universe is a rare occurrence.

Michael Bigwig

You guys are all mad.

You are arguing to suit your own needs...just to be right.

The sheer number of uninhabitable plants and the distance between them solidify my argument. RARE. Uncommon. If life was common, it would probably be found in our own solor system.

It's impossible to argue with know it alls. You spin things how you see fit.

Hell, you just rewrote the definition of 'rare'.

(and I'm talking about ALL forms of life) As long as you don't get all science fiction on me just to be right...which you're trying to.

Jessyanne

You all are stubborn.

Hiro Queso

Don Mill

Michael, rare implies and statistically analysis of the rate of one event in a defined universe (no pun intended).

If you can prove life is rare then tell me:

1) how large is the universe you are testing (how many planets are you considering there are in the universe?)

2) what is your sample population for that universe (how many planets are you testing from that universe?)

3) what is the result of your testing.

Unless you know any other way to claim that something is "rare".

Cindy Claveau

If you mean "complex life" or 'sentient life" you may be right (although see my post about defining 'rare').

But Life, including microbes and primitive algae, is very likely to be everywhere that geology and astrophysics opens the door a crack.

Don Mill

Europe has water? I blame the french and Evian!