Just a thought

[Washington]

​

 

[Chesterton]

"Next time you have a thought...let it go."
Ron White

 

[Tielec]

Isn't it amazing how fine-tuned the universe is to human life.

 

[Doveaman]

Just a thought

I agree. Apes don't think.

 

[Wiccan_Child]

I agree. Apes don't think.

Even though they can out-perform humans in some cognitive tests?

 

[Psudopod]

I agree. Apes don't think

Yes I do.

 

[Naraoia]

Yes I do.

That

And this:

 

[sandwiches]

Clearly the fact that 99.9999999999999999999999999% of the entire universe is hostile to human life is evidence of the anthropic principle, dontcha know?

 

[diychristian]

What a beautiful planet with just the right levels of oxygen and carbon dioxide and it has water! Look at that sitting right in the circumstellar habitable zone and around a yellow dwarf (which is perfect for photosynthesis). Our solar system is in a spiral galaxy! Cool! Why not in an elliptical galaxy? It's not too close to the center where all those heavy elements are. In fact, it's sitting right between the sagittarius and perseus arms. Whoa...that was a close one. Don't want to get in those arms. AH, I FEEL SO LOVED.

 

[Wiccan_Child]

What a beautiful planet with just the right levels of oxygen and carbon dioxide and it has water!

Just right for whom? Our lungs evolved to suit the atmosphere, not the other way around.

Look at that sitting right in the circumstellar habitable zone and around a yellow dwarf (which is perfect for photosynthesis).

Photosynthesis evolved to be perfect for the Sun, not the other way around.

Our solar system is in a spiral galaxy! Cool! Why not in an elliptical galaxy?

Why not indeed.

It's not too close to the center where all those heavy elements are.

There are heavy elements everywhere. I think you mean the high density of stars (which would be hazardous to life), and the supermassive black hole, that exist at the centre of the galaxy. Nothing to do with heavy elements.

In fact, it's sitting right between the sagittarius and perseus arms. Whoa...that was a close one. Don't want to get in those arms.

Why not? The arms aren't particularly dangerous. And besides, we're not in the arms now; we have been in the past, and we will be again in the future.

AH, I FEEL SO LOVED.

A heafty dose of statistical analysis will clear that right up.

 

[Naraoia]

Clearly the fact that 99.9999999999999999999999999% of the entire universe is hostile to human life is evidence of the anthropic principle, dontcha know?

I thought the anthropic principle was a pretty self-evident statement. Why exactly do you need evidence for it?

Our solar system is in a spiral galaxy! Cool! Why not in an elliptical galaxy?

Because M31 hasn't come over for a party yet?

 

[diychristian]

Just right for whom? Our lungs evolved to suit the atmosphere, not the other way around.
Photosynthesis evolved to be perfect for the Sun, not the other way around. "

Just right for life. Carbon and Water have properties that are not found anywhere else. They are essential for life. You give evolution and natural selection alot of credit, but they have no chance to play if they don't have a field to play on. If you're suggesting that n.s. can just make life in what ever conditions that are given then NASA and SETI need to stop narrowing their search for planets like ours and start looking at any ol' planet around any ol' star. NATURAL SELECTION CAN DO IT!

There are heavy elements everywhere. I think you mean the high density of stars (which would be hazardous to life), and the supermassive black hole, that exist at the centre of the galaxy. Nothing to do with heavy elements.

Heavy elements are everywhere. I was referring to the higher density, thank you.

Why not? The arms aren't particularly dangerous. And besides, we're not in the arms now; we have been in the past, and we will be again in the future.

Active star formations, supernovas and hazardous molecular clouds occur in the spiral arms. It's alot more hospitable in between. So we were chaotic in the beginning, there is now order and eventually there will be an end...sounds like what the Bible says. See there's science in the Good Book.

A heafty dose of statistical analysis will clear that right up.

Thanks doc. I was worried that my friends and family might catch that LOVE.

 

[diychristian]

Because M31 hasn't come over for a party yet?

Simple answer. I love it.

 

[Wiccan_Child]

Just right for life. Carbon and Water have properties that are not found anywhere else. They are essential for life. You give evolution and natural selection alot of credit, but they have no chance to play if they don't have a field to play on. If you're suggesting that n.s. can just make life in what ever conditions that are given then NASA and SETI need to stop narrowing their search for planets like ours and start looking at any ol' planet around any ol' star. NATURAL SELECTION CAN DO IT!

I agree, they should widen their search. That said, Earth-like planets are Earth-like: since we know that at least one Earth-like planet (i.e., Earth) harbour life, it's a good bet that other Earth-like planets also harbour life. But you're right, I think that life is phenomenally versatile, and can form in the absence of carbon and water (e.g., silicon has long been held as an alternative to carbon by xenobiologists).

I always baulk when sci-fi shows talk about alien DNA!

Active star formations, supernovas and hazardous molecular clouds occur in the spiral arms. It's alot more hospitable in between. So we were chaotic in the beginning, there is now order and eventually there will be an end...sounds like what the Bible says.

I thought the Bible said there were calm, waters of the deep, then paradise, then chaos and disorder?

See there's science in the Good Book.

There's also non-science in it. Gettit, non-science, nonsense? Oh, nevermind .

Thanks doc. I was worried that my friends and family might catch that LOVE.

Everyone knows real atheists shun love, instead preferring the tasty taste of babies.

 

[diychristian]

I agree, they should widen their search. That said, Earth-like planets are Earth-like: since we know that at least one Earth-like planet (i.e., Earth) harbour life, it's a good bet that other Earth-like planets also harbour life. But you're right, I think that life is phenomenally versatile, and can form in the absence of carbon and water (e.g., silicon has long been held as an alternative to carbon by xenobiologists).

I always baulk when sci-fi shows talk about alien DNA!

Hydrogen, helium, oxygen, and carbon are the most abundant elements in our universe, good luck trying to get away from them. Silicon is normally found with oxygen (quartz). Carbon is far more versatile than silicon; it is found in millions of organic molecules. Carbon is found in all known life. Even if silicon would replace carbon it would likely need water for any reactions to take place.

I thought the Bible said there were calm, waters of the deep, then paradise, then chaos and disorder?

Guess it depends on what color glasses you are looking through. One could argue that since God's Will will be done that everything is basically in order (I am not arguing this mind you). One could argue that the in creation week there was orderly chaos (earth without form, seperating light from dark, seperating water from water, etc. Sounds alot like when I unpack from moving, the place is a mess but my plan instills order into it), then creation was finished God rested, His children come home and make a mess (disorder).

Everyone knows real atheists shun love, instead preferring the tasty taste of babies.

There's got to be an Austin Powers reference here. I'll leave it alone.

 

[Wiccan_Child]

Hydrogen, helium, oxygen, and carbon are the most abundant elements in our universe, good luck trying to get away from them. Silicon is normally found with oxygen (quartz).

On Earth, perhaps. Who knows what foreign geology and meterology might yield.

Carbon is far more versatile than silicon;

They are virtually chemically identical. You can replace the carbon in any molecule with silicon, since they both have four bonds (thus allowing for the characteristic chain molecules found in life). This is why xenobiologists speculate that a silicon-heavy (or carbon-light) atmosphere doesn't necessarily preclude life: silicon works just as well as carbon.

One notable difference is that silicoids (the silicon equivalents of carbon-based molecules) burn more readily in our atmosphere. Though, of course, a lower oxygen concentration would sort that out.

Point is, carbon isn't necessary. It's useful, but I don't believe it is necessary.

it is found in millions of organic molecules.

It's found in all organic molecules, since an 'organic' molecule is one which contains carbon (a few carbon-based molecules are historically considered inorganic, but that's by-the-by).

Carbon is found in all known life.

See above. Also, key word: 'known'. All known life is on Earth, which has a carbon-heavy atmosphere.

Even if silicon would replace carbon it would likely need water for any reactions to take place.

See above. Given the electrochemical similarities between silicon and carbon, silicoid molecules would behave in much the same way as organic (i.e., carbon-based) molecules. Indeed, the majority of plants require silicon to survive.

 

[sandwiches]

What a beautiful planet with just the right levels of oxygen and carbon dioxide and it has water! Look at that sitting right in the circumstellar habitable zone and around a yellow dwarf (which is perfect for photosynthesis). Our solar system is in a spiral galaxy! Cool! Why not in an elliptical galaxy? It's not too close to the center where all those heavy elements are. In fact, it's sitting right between the sagittarius and perseus arms. Whoa...that was a close one. Don't want to get in those arms. AH, I FEEL SO LOVED.

Well, when you ignore how indifferent or outright hostile the universe seems to humans and just focus on Earth, you realize how horribly hostile this planet is, as well. 71% of the Earth surface is water, of that 2.5% fresh water, and only 1% of it is available to humans as the rest is in icebergs and glaciers. Now, of the 29% of land surface of Earth, 27% of it desert, leaving a total of 2% arable land of Earth with 1% drinking water. Yea... this planet was totally tailored for us, obviously.

 

[BrianOnEarth]

Sometimes things happen because they can. Not due to any volition. Misattribution error seems to be a universal pitfall.

There are lots of examples. Consider someone who wins the National Lottery - one person out of many millions. If we ignore all the millions of losers we might be inclined to endow the winner with special properties. Perhaps they are very skilled at choosing winning numbers. Or if our imaginations run too wild we might think the lottery system is sentient and deliberately choose that person to win and therefore we should endow the person with special significance. Of course, the person is no different to all the others - it was chance. The person is not a winner because they are special, they are a winner because winning is possible and they were lucky.

The same pitfalls occur when people think about the Earth and the physical properties necessary for life on Earth. Why do we ignore the losers?

Same with evolution. Humans endow themselves with special significance as a species, often denying that they are a species among many at all - "we are humans they are just animals". What if we are not humans because we are significant, we are humans because humans are possible and you and I are just lucky to be one of them?

 

[BrianOnEarth]

Another example. Suppose we meet and I hand you a normal looking dice. I ask you to roll it and note the number it lands on. Suppose I ask you to roll it 10 times. You do so and observe that each time it lands on six. What are you going to think about that?

I suggest the first thing you will think is that the dice is biased. I have handed you a trick dice that always lands on a six. That would be completely reasonable and rational because you know that the odds of an unbiased dice landing on six 10 times in a row is extremely small (it is about 1 in 60 million). Too much of a coincidence to be an unbiased dice.

But some people given the same experience might think that they are a lucky person. That there is something about them or some supernatural providence that is influencing the unbiased dice.

A delusional person might imagine that the dice is sentient and has chosen them and is performing with its own volition. "The dice is my friend", "the dice likes me/favours me"; perhaps even going as far as "the dice loves me". This sort of mis-attribution is probably common because we are relational beings and are predisposed to assume sentience in things that do not behave "randomly".

But given this experience what is the likelihood that a person will think it is pure chance. That the dice is not biased, that there is not supernatural providence at work and that the dice is not sentient? I think most people including myself would opt for the biased dice explanation if not one of the others. I think hardly anyone at all would reject all of these and claim it was pure coincidence.

However. It was, in fact, pure coincidence. I can convince you of this either by allowing you to roll the dice many more times and observe a different outcome to a six or I can inform you that I have done this experiment 60 million times with 60 million other people and you are the first one to roll ten sixes.

If you had known about the other 60 million experiments you would be happy to assume a coincidence and an unbiased dice. Without knowing about the other 60 million you will reasonably assume there is something special about the dice or something special about you. It is a reasonable misattribution error.

Do we know how many other Earth experiments are out there?

 

[MolecularGenetics]

What a beautiful planet with just the right levels of oxygen and carbon dioxide and it has water! Look at that sitting right in the circumstellar habitable zone and around a yellow dwarf (which is perfect for photosynthesis). Our solar system is in a spiral galaxy! Cool! Why not in an elliptical galaxy? It's not too close to the center where all those heavy elements are. In fact, it's sitting right between the sagittarius and perseus arms. Whoa...that was a close one. Don't want to get in those arms. AH, I FEEL SO LOVED.

I was going to respond with an explanation of probability, trials, and perception, but BrianOnEarth has beaten me to the punch with an explanation more insightful than the one I was planning (nice one, Brian).

So, instead, I’ll just post this response to the continuously habitable zone argument (the portion of the circumstellar habitable zone that remains habitable for a long period of time) that I wrote a while back (not for this site):

The formal statement of the argument is as follows:

The area around the Sun where a planet is capable of maintaining liquid water for a very long period of time, and thus, capable of sustaining life, is so vastly smaller than the dimensions of the solar system, that the fact that Earth happens to be within that area is unlikely to the point of being miraculous.
​

To understand where this argument breaks down, we first need to take a look at the anatomy of our solar system. Within the inner section, there is a cluster of terrestrial planets relatively close to the Sun, comprised of Mercury, Venus, Earth, and Mars. We then need to examine why the terrestrial planets formed so close to the Sun:

The heat from the proto-sun caused the area of the proto-planetary disk close to it to remain hotter than the outer regions. It would be hot enough to vaporize everything, so when it cooled, the condensates would be put in a radial order. The lighter, more gaseous elements would dissipate from the close, inner region, and only elements that melted at high temperatures would condense there (Nixon, 2006).
​

The CHZ of a main-sequence star like our Sun is located in this area. To get a rough measurement of the area’s dimensions, let’s use the inner edge of the asteroid belt as a marker, which is at about 2.1 astronomical units, or AU (Alfvén, 1976).

The only way the argument could hold any weight, is if the size of the CHZ is miniscule, relative to the size of this area where terrestrial planets are likely to form. Now, the process of calculating the CHZ of a star is difficult; due in part to the negative feedback loop generated by the carbon-silicate cycle:

[FONT=&quot]"[/FONT][Over time] the Earth's climate is stabilized against increasing insulation by [this] negative feedback… higher surface temperatures increase the precipitation, [which increases] the weathering rates resulting in decreasing atmospheric CO2 content and decreasing greenhouse effect (Franck et al., 2002). [FONT=&quot]"[/FONT]​

For these reasons, a degree of educated guesswork regarding geology and atmospheric conditions is necessary. Nonetheless, our Sun’s CHZ can be calculated. And although is it probably considerable larger, a very conservative estimate puts it extending from about 0.95 AU at its inner edge, to about 1.15 AU at its outer edge (Kasting, Whitmire, & Reynolds, 1993). That puts its diameter at about 0.2 AU, or about 19 million miles. When that figure is divided by the 2.1 AU of the planetary cluster area, we find that CHZ occupies at least 10% of it. That is quite a sizable chunk.

To say that, of the four terrestrial planets, it would be unlikely to the point of being miraculous, for just one of them to attain an orbit within a zone taking up about 10% of an area they’re likely to form in anyway, is unjustified—especially when one considers that there are hundreds of billions stars in our galaxy and tens of sextillions of stars in the visible universe. There are likely numerous main sequence stars with terrestrial planets in their CHZs.

The main problem encountered when trying to find them, of course, is the tremendous distances between ourselves and the other sections of our galaxy (let alone the billions of other galaxies out there).



References (if I had more than 50 posts under my belt, I could add links... sigh)

Alfvén, Hannes, and Gustaf Arrhenius. "4. The Small Bodies." 1976. United States. NASA. Scientific and Technical Information Office. NASA History Division.

Franck, S., W. Von Bloh, C. Bounama, M. Steffen, D. Schönberner, and H.-J Schellnhuber. "Habitable Zones and the Number of Gaia's Sisters." Ed. B. Montesinos, A. Gimenez, and E. F. Guinan. The Evolving Sun and Its Influence on Planetary Environments ASP Conference Series 269 (2002): 261-72.

Kasting, J. F., D. P. Whitmire, and R. T. Reynolds. "Habitable Zones around Main Sequence Stars." Icarus 101.1 (1993): 108-28.

Nixon, Conor. "ASTR 330: The Solar System." University of Maryland: Department of Astronomy. University of Maryland, 2006.

Purdy, Michael. "70,000,000,000,000,000,000,000 Stars in the Sky." The JHU Gazette [Baltimore] 4 Aug. 2003, Vol. 32., No. 41.