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Specific heat of Nickel/Iron 440j/(kg-K)
Temp ~6000K
Density of Iron 7800kg/m^3, Nickel 8900km/m^3
Diameter of outer core ~5000km
Mass of core = 5*10^24 kg, less than the mass of earth = 5.97*10^24
Heat content of core = 12*10^33 J, which combined with this data of 12 trillion kwh electricity usage/year = 43*10^18 J/year gives us over a billion years to drain it 1%, well past the life of our planet.

I saw a documentary a few years ago where geologists where saying the next big Ice Age was supposed to happen now.

15000 years ago 1 km of ice covered Scandinavia and half of Germany..I dunno about the U.S., but it isn't cool.

I live within a half mile of the terminal morraine. I'd have to move, but at least I could stay in the neighborhood. :)

Source, 1, 2, 3, md5sums. And remember - running software linked to by AC is fun! (No, seriously, the links are fine, sums good.)

Source, 1, 2, 3, md5sums. And remember - running software linked to by AC is fun! (No, seriously, the links are fine, sums good.)

Source, 1, 2, 3, md5sums. And remember - running software linked to by AC is fun! (No, seriously, the links are fine, sums good.)

Source, 1, 2, 3, md5sums. And remember - running software linked to by AC is fun! (No, seriously, the links are fine, sums good.)

Source, 1, 2, 3, md5sums. And remember - running software linked to by AC is fun! (No, seriously, the links are fine, sums good.)

On the balance of probabilities, it seems to me that right about 10-20 years ago we should have stopped buring the planet's carbon sinks and moved over to nuclear.

Limestone.

Hmm, ok maybe a few more words. One word is gonna whiz right over the heads of our computer science crowd ;-) Limestone = largest carbon deposits on earth, basically CaCO3. Created by plankton, the most abundant form of life in the ~2/3 of the planet we don't live on, known as the oceans. You've obviously been led to believe that most of the Earth's CO2 was caught in few small bogs several million years ago and that handful of rain forest was taking care of all the world's CO2 for us.

Take a nice long look at Table 9r-1 here. Notice how units (in billions of tons) of fossil fuels = 4,000, where 'Marine Sediments' = 66-100,000,000. If the diagram were 'to scale' that black representing the fossil fuels would be smaller than a pixel. The earth gets warmer, the earth gets cooler. Stuff like this happens. The idea that we are going to destroy our environment with CO2 is laughable.

You must unlearn what you have learned young jedi :-) The big scary "Global Warming" is a 90's save the earth fad. Thirty years previous, everyone was worried about the impending Ice Age! Have a nice day, and don't let the sky fall on ya ;-)

Essentially we're asking, "what is the fundamental difference between a biological organism and a machine" that "makes the former be considered 'alive'"

(1). Organisms tend to be complex and highly organized. Chemicals found within their bodies are synthesized through metabolic processes into structures that have defined purposes. Cells and their various organelles are examples of such structures. Cells are also the basic functioning unit of life. Cells are often organized into organs to create higher levels of complexity and function.

(2). Living things have the ability to take energy from their environment and change it from one form to another. This energy is usually used to facilitate their growth and reproduction. We call the process that allows for this facilitation metabolism.

(3). Organisms tend to be homeostatic. In other words, they regulate their bodies and other internal structures to certain normal parameters.

(4). Living creatures respond to stimuli. Cues in their environment cause them to react through behavior, metabolism, and physiological change.

(5). Living things reproduce themselves by making copies of themselves. Reproduction can either be sexual or asexual. Sexual reproduction involves the fusing of haploid genetic material from two individuals. This process creates populations with much greater genetic diversity.

(6). Organisms tend to grow and develop. Growth involves the conversion of consumed materials into biomass, new individuals, and waste.

(7). Life adapts and evolves in step with external changes in the environment through mutation and natural selection. This process acts over relatively long periods of time.

Of course, alive or not has little bearing on ethics it seems (and as you pointed out). We kill animals and plants for food and sport all the time. So, as you mentioned, the real question is probably "at what point is something to be considered 'sentient'?".

Cheers. :^)

this is such a bunch of tripe!

First of all.. if we were to take the encylopeadia Britannica and stack all the books up.. then the thickness of each page would represent more than 100,000 years of the earth's history. This means that the last ice age which ended about 10,000 years ago and was at peak 18,000 years ago would be within 1/5 of the thickness of the last page.

There were 8 ice ages in the last 2 million years and that is within the last 20 pages.

Within the last 2,000 years (2% of the thichness of the last page) there have been several warming and cooling periods denoted by such names as the little ice age and the medieval warm period . Crocs were in the themes during Roman times... (little warmer).

look here to see a chart showing global temperature over the last billion or so years. This is the paleomap project an they have done increadible work.

Check out the university of Carleton, Tim Patterson has an excellent course on climate change and this is being broadcast on TLC as well.

On Chris Scotese's web site you will see that for 90% of the history of the planet for the last 650 million years or so, the earth was about 20 degrees warmer than now. If you look at the miocene maps you will see that 14 Million years ago the planet was warmer.. and a lot wetter..

BTW... the time scale on Chris's chart is not linear. If the chart is re-scaled it tells the same story but is even more dramatic. (We leave the re-scalling to the student as an excersize).

Look here if you want to know why Britian is so keen on renewable energy and specifically look at these charts which show the decline rate of North Sea oil production. Britain will become an oil importer within 2 years. The decline rate of North Sea oil production is more than 15% per year. The chart shows how feilds deplete. You can see how the big plays are drilled first and last the longest... and thereafter smaller and smaller fields are brought online until they give up and stop drilling. This is where Britian is now. One of the stats is that Britian has about 250 barrels of oil per capita. That is it! On to renewable because the oil resource is gone.

The real issue of climate change is this. Water in the atmosphere is far more significant than CO2. Firstly H2O is at a far greater level so the question becomes... how would we express the level of H2O in the atmosphere? Secondly there is uncertainty in the measurements. Thirdly, irrigation and agriculture increase the H2O levels. Most of that water pumped onto the fields will evaporate and plants do transpire!

CO2 levels are in the range of 0.036% and this of course is a plant nutrient.

So we are left with adding 2 numbers for instance.

H2O = 0%-4.0% +/- what? a percent?
CO2 = 0.036% +/- 0.0005

You can see these numbers here in table 7a-1.

Since the warming response is most likely due to the weighted "sum" of the CO2 and H2O and all the other green house gasses of course, then we need to "add" the H2O levels to the CO2 levels. Well - the numbers are in the preceeding paragraph and I don't know how to add them. We don't even have a good handle on the uncertainty of the H2O levels... but, My guess is that irrigation and agriculture have increased the H2O substancially.

So - we end up with the anaolgy to the encyclopeadia. Almost all of the data for climate modeling has been collected in the last 100 years and this represents 1/1000'th of the thickenss of the last page of the stack of books. Meanwhile all the other pages are basically ignored. The geological history of the planet shows that the planet is usually (90% of the time) about 20 degrees warmer than now. So most likely the planet will warm back up. But we don't know when and we might get another ice age or several before this happens. Anyone for 10,000 feet of ice over Toronto? Who votes for palm trees in the artic circle?

But it's a while before we see a device like this replicate itself. That is the turning point.

My biology is a little rusty, but this seems like a big step in the direction of being defined as alive:

from http://www.geog.ouc.bc.ca/physgeog/contents/9a.htm l

(1). Organisms tend to be complex and highly organized. Chemicals found within their bodies are synthesized through metabolic processes into structures that have defined purposes. Cells and their various organelles are examples of such structures. Cells are also the basic functioning unit of life. Cells are often organized into organs to create higher levels of complexity and function.

(2). Living things have the ability to take energy from their environment and change it from one form to another. This energy is usually used to facilitate their growth and reproduction. We call the process that allows for this facilitation metabolism.

(3). Organisms tend to be homeostatic. In other words, they regulate their bodies and other internal structures to certain normal parameters.

(4). Living creatures respond to stimuli. Cues in their environment cause them to react through behavior, metabolism, and physiological change.

(5). Living things reproduce themselves by making copies of themselves. Reproduction can either be sexual or asexual. Sexual reproduction involves the fusing of haploid genetic material from two individuals. This process creates populations with much greater genetic diversity.

(6). Organisms tend to grow and develop. Growth involves the conversion of consumed materials into biomass, new individuals, and waste.

(7). Life adapts and evolves in step with external changes in the environment through mutation and natural selection. This process acts over relatively long periods of time.

Who is going to play mad-scientist and program in 4, 6, and 7? Would such a device be "alive"? The lines will blur...

Just some rampant speculation...cheers. :-)

First, chirality is not the same as "specific" shapes". Carbon dioxide is not chiral, but it has a specific shape. In the ground state it is a linear chain 0=C=0. Methane is not chiral; in its ground state it is tetrahedral.

Second, it's not at all obvious that chirality is required for life.

Third, silicon can form tetrahedal molecules. Silane, SiH_4 is an example.

Fourth, chirality is a property of the molecule as a whole, not of any particular atom in the molecule. If you want an example, consider hexahelicene. The molecule is chiral and yet the chirality can not be located at any one atom. It consists of six benzene rings joined together in a broken hexagon. A picture of this molecule can be found here.

Paul

(1). Organisms tend to be complex and highly organized. Chemicals found within their bodies are synthesized through metabolic processes into structures that have defined purposes. Cells and their various organelles are examples of such structures. Cells are also the basic functioning unit of life. Cells are often organized into organs to create higher levels of complexity and function.

(2). Living things have the ability to take energy from their environment and change it from one form to another. This energy is usually used to facilitate their growth and reproduction. We call the process that allows for this facilitation metabolism.

(3). Organisms tend to be homeostatic. In other words, they regulate their bodies and other internal structures to certain normal parameters.

(4). Living creatures respond to stimuli. Cues in their environment cause them to react through behavior, metabolism, and physiological change.

(5). Living things reproduce themselves by making copies of themselves. Reproduction can either be sexual or asexual. Sexual reproduction involves the fusing of haploid genetic material from two individuals. This process creates populations with much greater genetic diversity.

(6). Organisms tend to grow and develop. Growth involves the conversion of consumed materials into biomass, new individuals, and waste.

(7). Life adapts and evolves in step with external changes in the environment through mutation and natural selection. This process acts over relatively long periods of time.

Now it doesn't take a genius to conclude from this that embryos fail this "test". And you certainly worded your version to help your argument, and why not of course!

Want more? This simple google search will help those who want to settle this in their own minds.

FLAMEBAIT? He answers the question then adds a truthful insightful addition... you should be dragged out and shot. please read up on some basics of Systems Theory it does make a lot of sense...

Our college has a 67" smart board. 67" touchscreen with rear projection. It's absolutely amazing. The software has built in OCR. The instructor can use his finger to write, and then have it appear as typed text. In white board mode you can save anything you do, and go back to a diagram you drew 10 classes ago. I don't think I could say enough about it....it's just amazing.

I honestly don't see how our program could function properly without it. Like the microwave, I can't imagine life without it.

Is the way to finally break the main dilemma of the hydrogen economy? (That it takes more energy to make the hydrogen than you gain in using it.)

No. In order to do that, you would have to repeal the laws of thermodynamics.