How did gold appear in the universe?

[Genecks]

 

Yes, it's time to bring up discussion on something alchemists have tried to do for many millennia.

 

So, how did gold get here in the Universe and on Earth?

What's your big idea?

[Klaynos]

As a general rule, including gold:

 

Everything with a lower atomic mass than Fe (Iron) comes from nuclear fusion inside stars, everything with a higher atomic mass comes from supernovae.

[SkepticLance]

Klaynos has got the answer. Supernova done it!

 

Here on Earth, gold is concentrated in ores by hydrothermal action. Gold dissolves sparingly in ultra hot water. This is achieved by geothermal activity, where water is held in a liquid state at extreme temperature, since high pressure prevents it flashing off into steam. Eventually, the water travels over and through rock, dissolving gold, among other things, and releases the minerals as it cools. Since the minerals come out of solution at specific temperatures, they get concentrated into ores.

[iNow]

As for something more "down to Earth,"

 

 

http://www.newton.dep.anl.gov/askasci/gen99/gen99242.htm

Gold is formed as the result of molten rock, called magma, being intruded into solid rock. As the magma cools and solidifies, water and other volatile substances separate out from the magma under high pressure. The high pressure of hot water and steam force open fissures in the surrounding solid rock, through which these hydrothermal solutions travel. When the hydrothermal solutions cool, deposition of material occurs, especially quartz in the form of quartz veins.

 

Because gold has a relatively low melting temperature, it is sometimes carried by these hydrothermal solutions through the fissures in the rock and solidifies inside the quartz veins. Thus, the place to look for gold is usually in quartz veins near the intrusion of a magma body. One example is the so-called Mother Lode of the Sierra Nevada in California. If these quartz veins are eroded, the gold may be found in streams and rivers; this explains why the 49-ers of the last century were able to pan for gold in the foothills of the Sierra Nevada.

[Klaynos]

As for something more "down to Earth,"

 

 

http://www.newton.dep.anl.gov/askasci/gen99/gen99242.htm

 

More how it forms in seems in the crust than is created But nice and interesting all the same

[insane_alien]

yeah, the 'more down to earth' version still requires the gold atoms to exist. supernovae do not.

[Sisyphus]

I don't think he means it's an "alternate" version or something, just that perhaps a little more explanation is warranted for how something which could only be formed in the heat of a supernova ends up in little nuggets in the Earth's crust.

[Martin]

As a general rule, including gold:

 

Everything with a lower atomic mass than Fe (Iron) comes from nuclear fusion inside stars, everything with a higher atomic mass comes from supernovae.

 

this is a very good answer, but you could look at it in more detail.

 

supernovae explosions are able to produce elements of lower mass than iron

and they are able to EJECT all these elements

 

ordinary stars are able to fuse many of the elements up to and including iron, and they do blow off their outer layers, so as to disperse lighter elements into space----but I believe that in ordinary stars a lot of what they synthesize remains TRAPPED.

 

so I would suspect (something you might want to check Klaynos) that if you look at a piece of rock that you pick up and think about where the nuclei in that rock came from that you might decide that a lot of the nuclei LIGHTER than iron (as well as those heavier) might have had their origin in a supernova explosion.

 

(if they were made in the core of an ordinary star, how did they get here? and does the usual fusion chain from hydrogen up to iron touch all the nuclide bases?)

 

not criticism, just something to think about.

[Genecks]

So, if I can create and manipulate a supernova, then I can make gold? Ok, so what of the supernova makes the gold? Does anyone have a proof showing that a supernova can make gold? Has the process been observed in the universe by previous or contemporary scientists? Or is this some form of speculation?

 

I've often read that most stuff comes from hydrogen, which goes through various processes in order to become different elements. I'm not too sure about the factuality of that, though.

 

So, all I (as an alchemist) would need is a particle accelerator to make gold?

[geoguy]

Yes, it's speculation but educated speculation. A few atoms of heavier elements can be created in a laboratory situation with the right seed elements and sufficient energy. It's not a mystery as to what atoms need to be present and the amounts of energy needed to combine those elements into gold, lead, etc.

 

One reason that supernovae are probably the source of heavier elements is that they are the only phenomenon with sufficient mass and energy to produce the conditions necessary to build heavier elements. 'If' other phenomena could be discovered then these might also be a source of heavier elements. To date, however, there are no credible alternatives to supernovae.

[insane_alien]

we have also detected gold in the absorbtion(or emmission) spectra of supernovae indicating that this is the source. on normal star deaths this is absent.

[geoguy]

we have also detected gold in the absorbtion(or emmission) spectra of supernovae indicating that this is the source. on normal star deaths this is absent.

 

A question. If stars are sometimes made up of the 'stuff' of previous generations of stars (including those previous going supernova) then why wouldn't some of what you call 'normal stars' not have gold present in their spectra? They don't create the gold but it's already present.

 

(I'm over my head in all this so the question might not even be logical)

[insane_alien]

yes, some stars that have formed after the first wave of star formation (like our sun) will contain traces of heavier materials. but there is a difference in the level observed in supernovae and the level present in normal stars and star death.

 

the question was fine.

 

normal stars that formed in the first wave would contain nothing bigger than iron unless heavier elements fell into the star (which is possible if it travels through a supernova nebula.

[Genecks]

Are we talking about Au 79? I'm talking about obtaining the gold I could bring to a pawn shop. Perhaps I could buy a sandwich with the money from that gold.

[iNow]

To date, however, there are no credible alternatives to supernovae.

I think part of this is due to the robustness of this proposed mechanism:

 

We know stars get so hot that they fuse atoms into heavier elements. We know that stars can make elements all the way up to iron (26 protons). Once it's converted everything to iron, they're out of fuel.

 

Mathematically, we know enough chemistry to understand the fusion energies involved, and we can measuer the fusion energies of stars and other celestial events. Supernovae are the only events which we've observed which have the required energy. Of course this doesn't prove that there are no other mechanisms for heavier element formation, but it is an extraordinary probability that these explosions are the primary events.

 

 

Below is a link that is really simple and clear. It was presented on NPR (so you can listen to the story too!), and much of the data came from Dr. Neil deGrasse Tyson.

 

 

http://www.npr.org/templates/story/story.php?storyId=7397200

Only in a supernova is it possible to create atoms with 30 protons, 40 protons, 50 protons or even 60 protons. Nature prefers even numbers for stability, but every so often, the star will forge an odd-numbered atom, a real rarity: gold!

 

Gold is a rare, odd-numbered atom with 79 protons. For every single gold atom in the universe, there are 1 million iron atoms, Tyson says.