Colliding, Exploding Stars May Have Created All the Gold On Earth 133
coondoggie writes "Two dead stars smashing into each other and releasing massive amounts of energy may have created all of the heavy elements such as gold found on Earth. That's the main conclusion of Harvard-Smithsonian Center for Astrophysics (CfA) researchers who estimated such a collision and subsequent blast of energy known as a gamma-ray burst produced and ejected as much as 10 moon masses worth of heavy elements — including gold."
Re:Old news? (Score:5, Informative)
TFA/TFS is misleading. The reported discovery:
* is not about gold can be created only by the collision of two stars (the supernova nucleosynthesis [wikipedia.org] is still another channel, very probable the main one)
* is not about gold on Earth being originated in the collision of two start
* is about the collision of a neutron star which, besides producing a gamma-ray burst (due to acceleration of charged particles), have shown an afterglow characteristic to decays of "too neutron rich" nuclei into more stable elements (gold included)
Besides, the authors are not even sure
"We've been looking for a 'smoking gun' to link a short gamma-ray burst with a neutron star collision. The radioactive glow from GRB 130603B may be that smoking gun," said Wen-fai Fong, a graduate student at the CfA and a co-author of the paper.
Re:Old news? (Score:5, Informative)
The difference between this and the common knowledge is that the gold wasn't produced inside a single exploding star. As Neil deGrasse Tyson would eloquently phrase it - almost all the matter in our bodies and indeed on our planet is produced by a star going supernova and "spewing it's enriched guts throughout the cosmos".
For gold and some other heavy elements, the fusion of a star, even one going supernova, still can't produce these elements. These need a much bigger bang - that produced by TWO stars colliding together for a truly spectacular energetic detonation. The finding of these researchers isn't to suggest that this is just where gold on earth came from, but they're stating that all the heavy elements in the universe can only come about in similar cataclysmic events - rather than merely from a single star dying.
Re:Not first-generation supernovae? (Score:5, Informative)
I thought our heavy elements came mostly from the short-lived first generation of hypergiant hydrogen stars going supernova.
Supernova nucleosynthesis is still the main mechanism for creation of elements heavier than Fe. The guys report that they think other type of events may lead to the creation of heavy elements and they believe we already witnessed such an event [arxiv.org]
Re:Old news? (Score:5, Informative)
Not sure if that is true. Ordinary stellar nucleosynthesis can only produce elements up to iron, because nuclear fusion of iron or any other heavier element produces less binding energy per nucleon, and thus cannot be a viable means of producing energy for a star. The s-process [wikipedia.org] that takes place in stars prior to going supernova is capable of producing elements like gold, all the way up to bismuth. Heavier elements are produced by the r-process [wikipedia.org], that is supposed to occur in core collapse supernovae.
And to finish the thought... (Score:4, Informative)
In case anyone was wondering, Iron (Fe) is the limit to what is formed in convention fusion processes because any element heavier than iron takes more energy to fuse than is produced by the fusion. Iron and lighter fuse with an energy surplus, anything heavier requires an energy input and produces a deficit.