Hi, I'm a woolly mammoth. Me and my kind were mooping around on Earth for about 1.5 million years, my ancestors originally came from Africa but over 6 million years or so we spread out quite a bit. It was pretty cold up north and the poor mammoths that weren't as woolly died out and soon we were all woolly. We died out completely around 10000 years ago, we know this because you guys haven't found any of my kind younger than that.
The creationists claim I died out in a giant flood which wiped the Earth clean of all life (apart from what Noah could fit on his boat). These guys claim I was around for about 2000 years, after some guy created the Earth 6000 years ago.
So when did I really live?
Well according to my digital watch synced with the atomic clocks in Germany I was born on the 17th of October 36000 years ago. Oh dear, for that time I must have been floating around in nothing, because apparently there wasn't an Earth or anything else. Well I can tell you first hand that was pretty wrong, I was definitely mooping around somewhere above the frozen North Sea 36000 years ago (we had GPS too).
We know I'm telling the truth (well I might be exaggerating a little bit about the digital watches and GPS) because you can date me from my carbon-14 atoms.
Normally all life on Earth is made up of carbon-12 and carbon-13. But a certain percent is carbon-14, this percentage is the same in all life on Earth. It happens like this:
Cosmic rays are constantly hitting the Earth from space. In fact every day a person is hit about 8000 times a minute by cosmic rays as you can tell they usually don't do a lot. But sometimes a cosmic ray neutron will hit an atom of nitrogen in the atmosphere, actually a nitrogen-14 atom (7 protons, 7 neutrons). As the neutron smashes into the atom it knocks a proton away (a hydrogen atom) and adds itself to what was the nitrogen-14 atom, this is an atom with 6 protons and 8 neutrons - which is a carbon-14 atom.
Through photosynthesis plants suck up CO2, which includes carbon-14 atoms. This is how these atoms find their way into all life on Earth. A certain percent of the plant will be made from carbon-14 atoms, if an animal eats the plant a certain percent of his body will also be made from carbon-14 and if somebody else eats him he'll have that percentage of carbon-14. These carbon-14 atoms make up 0.0000000001% of all carbon on Earth.
The cool thing about carbon-14 though is it's unstable, it's radioactive. It has a half-life of about 5730 years. So if we've got some carbon-14 atoms, within 5730 years half of them would of decayed through the process called radioactive decay they'll turn back into a nitrogen-14 atoms, we can use these atoms to date things to about 60000 years - the amount of time it takes for most of the atoms to decay completely. That's how we work it out, we work out the number and type of atoms I'm made out of.
This is how scientists can work out roughly how old I am, it's called radiocarbon dating, it's not accurate enough to days, or even years, but it's accurate to within a few hundred years. So they can work out and tell that I'm not lying when I say I'm 36000 years old.
So why do you creationists call me a liar?