Evolution on earth vs around the universe

[Moontanman]

if you remove anthropocentric,

then what is real ?

 

 

MY question is how do you remove it, it is us...

[D H]

my question is, why does it have to be earth like,

it's possible that only humans need an earth like planet,

and not necessarily other species that exist.

 

thinking above anthropocentric

 

 

It's not just humans. It's all of life as we know it. Admittedly that's reasoning from a sample of one, but there are good solid reasons to think that that line of reasoning is valid. Let's start with chemistry. Imagining non-carbon life is a favorite theme amongst science fiction authors. It's inevitably poorly done. Carbon is a very unique element. There's nothing quite like it. Not even close.

 

Imagining non-water based life is another favorite sci fi theme. Water is a rather unique compound. Once again there's nothing quite like it. The analogs are near as universal a solvent as is water, and they are liquid at significantly lower temperatures. Those lower temperatures create a big problem with those water analogs. Everything proceeds at a slower pace. It took evolution more than half of the available time during which Earth will be hospitable to life to produce intelligent life. Even if those water analogs somehow are hospitable to life, the significantly slower chemistry means intelligent life has a vastly reduced chance of arising.

 

Finally, suppose that contrary to the above lines of reasoning, there is some form of life that doesn't rely on carbon/water chemistry. What would we look for? How could we know that it was life if we were staring it straight in the face, let alone dozens of light years or more away? The answer is we couldn't.

 

 

Next thing is, why a terrestrial planet? Once again, one simple reason is that we don't know how to look elsewhere. Suppose simple life exists somewhere deep within Jupiter's thick atmosphere. That life will be hidden from us for a long, long time, and that life is forever doomed to remain primitive. Another reason is that ultimately we are looking to find intelligent life or to find a place where humans might eventually go. Intelligent life here means life with which we can communicate, remotely. That hypothesized life deep within Jupiter is doomed to be primitive forever. The same would go for life on Venus.

 

We're looking for a planet with a surface gravity that isn't much more than Earth gravity; we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher. We're looking for a planet that has a transparent atmosphere. Would we have looked to the stars if we couldn't see the stars? We're looking for a planet that is hospitable to life based on carbon, hydrogen, oxygen, and nitrogen. All of these say to look for terrestrial planets that are very close to Earth.

[krash661]

It's not just humans. It's all of life as we know it. Admittedly that's reasoning from a sample of one, but there are good solid reasons to think that that line of reasoning is valid. Let's start with chemistry. Imagining non-carbon life is a favorite theme amongst science fiction authors. It's inevitably poorly done. Carbon is a very unique element. There's nothing quite like it. Not even close.

 

Imagining non-water based life is another favorite sci fi theme. Water is a rather unique compound. Once again there's nothing quite like it. The analogs are near as universal a solvent as is water, and they are liquid at significantly lower temperatures. Those lower temperatures create a big problem with those water analogs. Everything proceeds at a slower pace. It took evolution more than half of the available time during which Earth will be hospitable to life to produce intelligent life. Even if those water analogs somehow are hospitable to life, the significantly slower chemistry means intelligent life has a vastly reduced chance of arising.

 

Finally, suppose that contrary to the above lines of reasoning, there is some form of life that doesn't rely on carbon/water chemistry. What would we look for? How could we know that it was life if we were staring it straight in the face, let alone dozens of light years or more away? The answer is we couldn't.

 

 

Next thing is, why a terrestrial planet? Once again, one simple reason is that we don't know how to look elsewhere. Suppose simple life exists somewhere deep within Jupiter's thick atmosphere. That life will be hidden from us for a long, long time, and that life is forever doomed to remain primitive. Another reason is that ultimately we are looking to find intelligent life or to find a place where humans might eventually go. Intelligent life here means life with which we can communicate, remotely. That hypothesized life deep within Jupiter is doomed to be primitive forever. The same would go for life on Venus.

 

We're looking for a planet with a surface gravity that isn't much more than Earth gravity; we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher. We're looking for a planet that has a transparent atmosphere. Would we have looked to the stars if we couldn't see the stars? We're looking for a planet that is hospitable to life based on carbon, hydrogen, oxygen, and nitrogen. All of these say to look for terrestrial planets that are very close to Earth.

are you referring to carbon 12 ?

[Moontanman]

It's not just humans. It's all of life as we know it. Admittedly that's reasoning from a sample of one, but there are good solid reasons to think that that line of reasoning is valid. Let's start with chemistry. Imagining non-carbon life is a favorite theme amongst science fiction authors. It's inevitably poorly done. Carbon is a very unique element. There's nothing quite like it. Not even close.

 

Actually Boron chemistry is at least as complex as Carbon chemistry but it does suffer from being rare. Boron forms "bucky balls" like Carbon as well, an interesting fact since carbons "unique" chemical flexibility allows it to do so.

 

I am going to say before i go on that i would be amazed if life turned up not based on carbon.

 

http://www.daviddarling.info/encyclopedia/B/boron-based_life.html

 

Imagining non-water based life is another favorite sci fi theme. Water is a rather unique compound. Once again there's nothing quite like it. The analogs are near as universal a solvent as is water, and they are liquid at significantly lower temperatures. Those lower temperatures create a big problem with those water analogs. Everything proceeds at a slower pace. It took evolution more than half of the available time during which Earth will be hospitable to life to produce intelligent life. Even if those water analogs somehow are hospitable to life, the significantly slower chemistry means intelligent life has a vastly reduced chance of arising.

 

The life chemistry we know would indeed be slow at the temps of liquid ammonia but it's conceivable that more unstable molecules would be stable at lower temps and more suitable to life. Silicon, not silicone, could be a possible life element in liquid methane, in fact some speculation has been bandied about around this and Titan. Silanes are more stable at low temps and would dissolve in methane quite easily. Of course there are many possibilities

 

Finally, suppose that contrary to the above lines of reasoning, there is some form of life that doesn't rely on carbon/water chemistry. What would we look for? How could we know that it was life if we were staring it straight in the face, let alone dozens of light years or more away? The answer is we couldn't.

 

I think this could very well be possible even if it was carbon based life. We simply don't know...

 

Next thing is, why a terrestrial planet? Once again, one simple reason is that we don't know how to look elsewhere. Suppose simple life exists somewhere deep within Jupiter's thick atmosphere. That life will be hidden from us for a long, long time, and that life is forever doomed to remain primitive. Another reason is that ultimately we are looking to find intelligent life or to find a place where humans might eventually go. Intelligent life here means life with which we can communicate, remotely. That hypothesized life deep within Jupiter is doomed to be primitive forever. The same would go for life on Venus.

 

Planets with deep hydrogen atmospheres but not gas giants could be suitable for life quite far out from a star, hydrogen is a very good greenhouse gas and a super terrestrial planet could hold a hydrogen atmosphere.

 

We're looking for a planet with a surface gravity that isn't much more than Earth gravity; we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher. We're looking for a planet that has a transparent atmosphere. Would we have looked to the stars if we couldn't see the stars? We're looking for a planet that is hospitable to life based on carbon, hydrogen, oxygen, and nitrogen. All of these say to look for terrestrial planets that are very close to Earth.

 

 

I disagree and so does NASA... I saw a video a few days ago about this, i was surprised to find out that super terrestrial planets with hydrogen atmospheres could support liquid water out to the orbit of jupiter, this would not be a gas or ice giant but a large Earth type planet with a mostly hydrogen atmosphere. This would be hospitable to life as organisms on the earth metabolize hydrogen. I'll see if i can find the article, it was very interesting, an eye opener to me.

 

This site has a list of possibilities, rather speculative but still interesting...

 

http://www.daviddarling.info/encyclopedia/A/alternative_forms_of_life.html

[krash661]

planet interiors

 

also, keep in mind, nasa is not transparent.

[D H]

Actually Boron chemistry is at least as complex as Carbon chemistry but it does suffer from being rare. Boron forms "bucky balls" like Carbon as well, an interesting fact since carbons "unique" chemical flexibility allows it to do so.

 

I am going to say before i go on that i would be amazed if life turned up not based on carbon.

 

I should have prefaced what I said about carbon with "common". Boron is anything but common. It is exceedingly rare.

 

 

Planets with deep hydrogen atmospheres but not gas giants could be suitable for life quite far out from a star, hydrogen is a very good greenhouse gas and a super terrestrial planet could hold a hydrogen atmosphere.

 

Hydrogen is *not* a "very good" greenhouse gas. Hydrogen is a diatomic gas. The molecules in a greenhouse gas are triatomic or more.

 

That's neither here nor there, however. Once again, suppose one of those super-Earths / sub-Neptunes that have been found did harbor life deep inside it's atmosphere. How could we possibly know? How could that life possibly be intelligent? Here I'm using intelligent to mean able to communicate with other life and able to build devices capable of escaping their planet's atmosphere.

 

A hydrogen atmosphere would be particularly problematic for life. If such a planet did harbor life, how could that life be anything but extremely primitive? Certainly there's no photosynthesis. Oxidizers and hydrogen don't go mix all that nicely.

 

 

I disagree and so does NASA...

 

Disagree with what? That we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher? That's a simple fact of the limits of chemical propulsion. We're lucky that outer space is within our grasp via chemical propulsion. That Kepler's ultimate goal isn't to find terrestrial planets? Those exoplanets larger than Earth-sized are freebies. The ultimate goal, however, is to find Earth-like planets.

 

 

 

planet interiors

 

What, exactly, are you saying about planet interiors? How, exactly, are we going to look at the interior of any planet other than our own?

 

also, keep in mind, nasa is not transparent.

 

What, exactly, is this supposed to mean? You've spouted this nonsense multiple times before.

[krash661]

What, exactly, are you saying about planet interiors? How, exactly, are we going to look at the interior of any planet other than our own?

 

What, exactly, is this supposed to mean? You've spouted this nonsense multiple times before.

 

it's simple,

the problem is obvious,

which is you do not understand anything i have stated,

you are so quick to rush to a argument,

just stop and think,

 

simple.

 

edit-

 

Disagree with what? That we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher? That's a simple fact of the limits of chemical propulsion. We're lucky that outer space is within our grasp via chemical propulsion. That Kepler's ultimate goal isn't to find terrestrial planets? Those exoplanets larger than Earth-sized are freebies. The ultimate goal, however, is to find Earth-like planets.

 

it also appears you do not understand the topic and conversation.

 

 

edit 2 -

 

lol typical, gives me a negative point,

funny.

grow up.

Edited June 22, 2013 by krash661

[Moontanman]

 

I should have prefaced what I said about carbon with "common". Boron is anything but common. It is exceedingly rare.

 

 

 

Hydrogen is *not* a "very good" greenhouse gas. Hydrogen is a diatomic gas. The molecules in a greenhouse gas are triatomic or more.

 

That's neither here nor there, however. Once again, suppose one of those super-Earths / sub-Neptunes that have been found did harbor life deep inside it's atmosphere. How could we possibly know? How could that life possibly be intelligent? Here I'm using intelligent to mean able to communicate with other life and able to build devices capable of escaping their planet's atmosphere.

 

A hydrogen atmosphere would be particularly problematic for life. If such a planet did harbor life, how could that life be anything but extremely primitive? Certainly there's no photosynthesis. Oxidizers and hydrogen don't go mix all that nicely.

 

 

 

Disagree with what? That we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher? That's a simple fact of the limits of chemical propulsion. We're lucky that outer space is within our grasp via chemical propulsion. That Kepler's ultimate goal isn't to find terrestrial planets? Those exoplanets larger than Earth-sized are freebies. The ultimate goal, however, is to find Earth-like planets.

 

 

 

 

Here is the info about hydrogen planets, the graph is around 20:00.

 

 

Isaac Asimov proposed a photosynthesis driven saturation unsaturation cycle in a hydrogen atmosphere.

[D H]

it's simple,

the problem is obvious,

which is you do not understand anything i have stated,

you are so quick to rush to a argument,

just stop and think,

 

simple.

 

I did not ask you to be obtuse.

I did not ask you to wax poetic.

I did not ask you to insult.

 

I simply asked you to explain what you meant. Is it that hard?

 

BTW, it would be nice if you answered without attempting to be poetic. This is scienceforums.net. Try to use prose.

 

 

it also appears you do not understand the topic and conversation.

 

Read the opening post. It's not about primitive extremophiles, which is presumably what you were addressing with your comment about a planet's interior. The question at hand is intelligent life. Here's the intro to the opening post:

 

 

So I'm always hearing that humans are such a young species and that there's probably much more complex life out there in the universe somewhere. I always agreed with that statement and didn't think anything of it until recently..

I thought, there has been life on earth for billions of years now and it's only now that intelligent beings are coming about, meaning that it takes a long time for evolution to figure it out. Give or take a few million years, who knows if any other species could do it much faster? You don't just pop into existence as galaxy roaming super aliens.

 

So, getting back on topic, our sun is a young star, about 1/3 the age of the universe. Of all the other planets that could theoretically harbor intelligent life there certainly must be some that are significantly older than is our sun. It's not just millions of years by which other stars/planets might be ahead of us. It's billions of years.

 

So why are we here, and where are they? That's the Fermi paradox. To me, the easiest answer is that intelligent life is extremely rare. We might never talk to them, see them, see any sign that they exist.

[krash661]

I did not ask you to be obtuse.

I did not ask you to wax poetic.

I did not ask you to insult.

 

I simply asked you to explain what you meant. Is it that hard?

 

BTW, it would be nice if you answered without attempting to be poetic. This is scienceforums.net. Try to use prose.

the problem here is,

i'm not " poetic " or " obtuse ",

at all.

i'm clear in what i stated.

it appears the problem is your comprehension.

it appears you did not read anything i stated or did not know anything about the references is used,

then ran your mouth so quick to rush to a argument.

 

typical.

[D H]

i'm clear in what i stated.

Twice now you have cryptically stated that NASA is not transparent. Twice now you have been challenged. You've said *nothing*.

 

You also cryptically said "planet interiors". That's anything but clear. I asked for a simple clarification. How, exactly, are those two words at all related to the topic at hand?

[krash661]

 

ok agian,

Twice now you have cryptically stated that NASA is not transparent. Twice now you have been challenged. You've said *nothing*.

this is not cryptic at all,

it's your lack of understanding,

the lack is it's obvious you have no clue this word is used to describe

" not tell and show all " behavior.

simple.

You also cryptically said "planet interiors".

again, not cryptic at all,

the post above me(if you actually read it) stated about surface of planets,

think about planet interiors.

again simple.

[EdEarl]

These recent posts seem to be going around the universe without discussing evolution on earth. I, too, do not understand your point(s) karsh.

[hypervalent_iodine]

!

Moderator Note

krash, you've been warned before about the attitude you display in your posts. We do not permit members to attack others in this forum. You are welcome to attack ideas, but criticizing the person making them is not acceptable.

 

It would also be advisable for you to make some sense and cut the vague conspiracy nonsense (in other words, stick to the topic). If you wish to talk about your speculations, we have a forum for that.

[krash661]

type zero planet

[swansont]

type zero planet

!

Moderator Note

Explain, please. Not really fitting the requirement of making more sense. This is starting to get old.

[Moontanman]

I should have prefaced what I said about carbon with "common". Boron is anything but common. It is exceedingly rare.

 

 

 

Hydrogen is *not* a "very good" greenhouse gas. Hydrogen is a diatomic gas. The molecules in a greenhouse gas are triatomic or more.

 

That's neither here nor there, however. Once again, suppose one of those super-Earths / sub-Neptunes that have been found did harbor life deep inside it's atmosphere. How could we possibly know? How could that life possibly be intelligent? Here I'm using intelligent to mean able to communicate with other life and able to build devices capable of escaping their planet's atmosphere.

 

A hydrogen atmosphere would be particularly problematic for life. If such a planet did harbor life, how could that life be anything but extremely primitive? Certainly there's no photosynthesis. Oxidizers and hydrogen don't go mix all that nicely.

 

 

 

Disagree with what? That we ourselves wouldn't have been able to go into space if Earth gravity had been slightly higher? That's a simple fact of the limits of chemical propulsion. We're lucky that outer space is within our grasp via chemical propulsion. That Kepler's ultimate goal isn't to find terrestrial planets? Those exoplanets larger than Earth-sized are freebies. The ultimate goal, however, is to find Earth-like planets.

 

 

 

 

What, exactly, are you saying about planet interiors? How, exactly, are we going to look at the interior of any planet other than our own?

 

 

What, exactly, is this supposed to mean? You've spouted this nonsense multiple times before.

DH did you watch the video I posted about hydrogen as a greenhouse gas? I'd like to know how accurate the NASA scientist was....