h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Does anything other than fire metabolize pure carbon? Paleontologists date millions of year old fire pits by the charcoal. How long does the stuff last?

try this from post 835 http://www.bbc.co.uk/dna/h2g2/brunel/F16034?thread=6311115&skip=820&show=20 clive go's into some detail about the different methods of dating fire pits won't be millions of years old as 'man' is only about a million years old and i use 'man' in the loosest perms

Scientists use carbon 14 to date things. It is a radioactive isotope of carbon with a known rate of decay into the stable carbon 12 isotope.

Carbon has been around in the Universe for a very long time. If the Universe is 13.7 Billion years old (give or take a day or two) then the first carbon would have been created in the first stars to form. They would be short lived, massive stars which formed in the first million years and would have lasted a few million years.

Carbon 12 will last for the life of the universe although in the arguably inevitable heat death of the universe matter will decay into degenerate states leaving a cold, thin soup of particles.

Not in the next couple of weeks so we will be OK.

Check out W*k*pedia http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang and then look at the Ultimate Fate Wiki page linked from this one.

t.

That tells us what is going to happen to the atoms of Carbon, turvy, but it doesn't tell us whether anything will react chemically with the carbon in Charcoal.

I should have explained why I was asking.

When tree is alive it sucks the greenhouse gas CO2 out of the atmosphere. Which is good for global warming. When it dies it keels over and, whether or not it makes a sound or anyone hears it, it rots and sends the CO2 back. Which is bad for global warming.

What if you turned the tree into charcoal? How long would the carbon stay locked up in the ground and out of the atmosphere?

"How long does the stuff last?"

I answered this question in one way but not, I guess in the way it was intended.

This site might have the answer - http://www.technologyreview.com/Energy/18589/ .

I recall there was a piece on the same topic in New Scientist a while ago.

t.

if we stopped using fossil fuel we would not be putting stored away carbon back into the atmosphere

tectonic activity would then be the main way of recycling carbon

tree - coal - volcano - co2 into the air - tree - etc. etc.

if we were to switch to charcoal it would be

tree - charcoal - co2 into the air - tree

and carbon level would stay aound the same

i think i know what you are on about

if we started to refill the coal mines with charcoal we would bring down co2 levels

its just that tectonic activity would release it at some point

Turvy, thank you for that link. I now know way more about the idea than I did before.

Taff, it's true that stopping the use of fossil fuels will stop the increase in greenhouse gas but that's just not going to happen any time soon and I was thinking in practical terms to reduce the carbon now.

I was thinking that the lowest cost way of doing this would be to turn trees into charcoal in situ then leaving the carbon where the tree grew.

The technology of walking robots is well established so I see a semiautonomous stick insect walking through the boreal forest. It would pick a tree at random or by whatever protocol you want, then engulf the tree by sitting on it. The abdomen of the robot is a tube where the pyrolysis takes place. The energy to power the robot would come from the energy rich byproducts of that pyrolysis.

I didn't know about Branson's $25M prize. It might make it worthwhile to develop the idea.

The trouble is that life is already trying to achieve what your autonomous robots would do, and it is doing it with ~someNumber of years of selection and mutation behind it. There is an energy equation which is very hard to balance.

In general, creating a fuel with a high energy density (such as fossil fuels) takes an extraordinarily large amount of energy in the first place. Nuclear fission obviously breaks this rule, but chemical reactions don't.

Sorry Bouncy, but you're wrong with the Nuclear Fission comment. Creating Elements further along the periodic table takes more and more energy. The only place (as far as I know) that has enough energy to make it happen is the inside of a star.

i read some where that stars have an 'iron limit'

old stars burn heavier and heavier fuels producing heavier waste the limit a star can go to is producing iron as waste, all other elements after this are only produced when a star go's nova

True. Only relitavely massive stars will get as far as Iron. After Iron it takes too much energy to create larger elements during normal nuclear fusion processes. To get higher elements there has to be an enormous energy input and a supernova is it.

Once Iron is reached at the core of these stars there isn't enough outward pushing energy to resist the pull of gravity so the core collapses. Then the outer layers of the star collapse onto the compressed core and it all explodes in a orgy of destruction (love that phrase) for the star. This leaves behind a compressed remnant (usually a neutron star) and an expanding sphere of star stuff containing heavier elements.

http://www.seds.org/hst/SN1987A_Rings.html
http://www.seds.org/hst/CygnusLoop.html
http://upload.wikimedia.org/wikipedia/commons/0/00/Crab_Nebula.jpg

Our sun is not massive enough to go supernova so you can relax for now. It might end up like this though - http://www.seds.org/hst/Hourgls.html or http://www.seds.org/hst/NGC6543a.html

t.