Star light, star bright,
Ten billion years ago,
I need to ask a question
Cos I really want to know:
The carbon in our bodies came
From ancient stars’ collapse;
I’ve heard it from a poet
Or a physicist, perhaps
But is it true, as some have said
(I can’t believe it, quite),
That different stars made atoms
For my left hand and my right?
Or could it be, my love and I
Were once the self-same star,
Together for eternity
In time and space, so far?
Something I have wondered for years--probably from about six seconds after I first heard about how heavier elements were formed--is, how was (is) the matter from exploding stars distributed? Space is, as Douglas Adams noted, big. "[V]astly, hugely, mind-bogglingly big." If a star goes supernova, how widely would its heavier elements be distributed? Would the majority of the "star stuff" coalesce into just a relative handful of relatively local gravity sinks, or could we expect a relatively small amount in any one relatively local area (and yes, I thought about each of those relatives; it's my version of Drake's equation).
Lawrence Krauss, in his wonderful "A Universe From Nothing" talk, gives one answer:
Every atom in your body came from a star that exploded. And, the atoms in your left hand probably came from a different star than your right hand. It really is the most poetic thing I know about physics: You are all stardust. You couldn’t be here if stars hadn’t exploded, because the elements - the carbon, nitrogen, oxygen, iron, all the things that matter for evolution and for life - weren’t created at the beginning of time. They were created in the nuclear furnaces of stars, and the only way for them to get into your body is if those stars were kind enough to explode. So, forget Jesus. The stars died so that you could be here today.On the other hand, Tony Piro's "Calamities of Nature" claims "we're all born from the death of the same star"
(Click to see the whole thing.)
Anyway, I want to know. And here's the beautiful thing. Once upon a time, we would have made up some answer, something that made us feel good, or superior, or something that allowed the teller to pretend to know more than he or she did. Something that probably started "once upon a time". Or "in the beginning...". But now, we can actually answer the question. It doesn't matter which I think is cooler, or more romantic, or more commonsensical. There is a right answer, and if there aren't people who know it right now, there is a methodology that allows us to eventually get there.
Assuming our own star doesn't blow up first.
Anyway, I've got great commenters here, and I'm hoping one of you knows, or knows someone who knows. How many stars died to make me? Are my right and left hands from different stars (seems impossible to me, given that they came from the same food and air I've been taking in over my lifetime, so I suspect Krauss was using a bit of poetic license, actually meaning that our entire bodies are composed from the remains of many stars--but how many?)?
I want to know.