Not enough, as I see it, for a real topic, but Infixion mentioned an argument his brother had used
here. In short, it was "that the universe couldn't be billions of years old because of the overwhelming abundance of hydrogen in the universe."
Fishy, thought I, so I got out an astronomy handbook and a calculator. Let's look at our own sun as a representative hydrogen-burner, and see what comes out: the Sun's mass is 2 X 10^30 kg, and we can assume that it started out 4.5 billion years ago with about 75% of that as hydrogen (and nearly all the rest helium.) The Sun puts out 3.85 X 10^26 watts, AKA Joules per second, of power.
We can apply Einstein's E=mc^2 to this amount of power - 3.85 X 10^26 = m X (3 X 10^8)^2 means that the furnace in there converts 4.3 X 10^9 kilograms - 4.3 million tonnes - of mass to energy every second. Again, we'll assume that essentially all that energy comes from hydrogen fusion to helium. In that process, each 4.031300 grams of hydrogen consumed yields a mole of helium and converts 0.0287 gram of mass to energy. That 4.0313 grams is 140 times the mass that disappears, so our 4.3 million tonnes of lost mass represents 140 times as much hydrogen processed into helium and energy. In numbers, 6.04 X 10^11 kilograms of hydrogen disappears every second.
Sounds like a lot, huh? Let's take that amount times the time since the Sun formed - 4.5 billion years times 365.25 days times 86,400 seconds in a day - and we have a total hydrogen consumption of 8.5 X 10^28 kilograms since the start. Now compare that to the mass of hydrogen we started with, 1.5 X 10^30 kg, and you'll see that less than 6% of the initial supply is gone as of today.
I know that I've simplified a lot - constant energy output and such - but I think you could take this back to whup up on your brother with, Infixion.
This message has been edited by Coragyps, 05-05-2006 09:04 PM
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