Question about the formation of the earth and its elements

I am of the understanding that almost all of the elements heavier than
Helium - and specifically including the the elements that make up the
earth - were formed earlier in the lifetime of the Universe in stars that
supernova.

Do we know which supernova? Shouldn't it/they have left behind neutron stars
or black holes that we could see today? Or is it more likely that many
widely separated supernova contributed the matter that makes up the earth,
and so the earth has many "parent" stars?

On Jan 27, 3:06*pm, "Peter Webb"
wrote:
I am of the understanding that almost all of the elements heavier than
Helium - and specifically including the the elements that make up the
earth - *were formed earlier in the lifetime of the Universe in stars that
supernova.

Do we know which supernova? Shouldn't it/they have left behind neutron stars
or black holes that we could see today? Or is it more likely that many
widely separated supernova contributed the matter that makes up the earth,
and so the earth has many "parent" stars?

In 1990 I showed that stellar evolution may be more than a one stage
process from beginning to end and the higher elements may have been
created by our own Star in a different phase of its evolution.The
particular geometry I used was two large external rings with a
smaller intersecting smaller ring denoting the efficiency of the
stellar evolutionary process and derived a quiet satisfaction of the
1994 images of SN1987A -

http://www.ps.uci.edu/~superk/pic/sn1987a.gif

There is nothing critically wrong with the understanding of stellar
evolutionary process at present even though it does not allow for a
major phase development,it just may be far more interesting to
consider the particular geometries surrounding the efficiency issue as
I did in 1990 -

http://www.grantchronicles.com/etacarinaebig.jpg

In any case,it is mostly a private work now due to the prevailing
circumstances surrounding astronomy and geometry.

"Peter Webb" wrote in message
u...
I am of the understanding that almost all of the elements heavier than
Helium - and specifically including the the elements that make up the
earth - were formed earlier in the lifetime of the Universe in stars that
supernova.


This is a commonly-held but erroneous view. Supernovae are by no means the
only source of heavy elements, though they are important.

Elements formed in the Big Bang include H, He, Li, and Be. Heavier elements
were (and still are) formed in stars and returned to the interstellar medium
where they are incorporated in new stars and planets.

Elements from B through Fe (and Co and Ni) are formed in the interiors of
evolving stars through successive fusion stages that release energy.
Depending on the mass of the stars, this stops at different stages. During
this stellar evolution, at certain stages nuclear reactions release neutrons
that react with iron and other existing heavy nuclei, slowly building up
heavy elements (or certain isotopes of heavy elements). This enriched
material is released back into the interstellar medium through stellar winds
and production of planetary nebulae.

Stars above a certain mass collapse at the end of iron-formation and become
Type II supernovae. During the moments of the implosion-explosion and
expansion, the matter is flooded with neutrons and heavy elements are also
formed rapidly (other isotopes--some isotopes can be formed by both
processes). This can end in formation of a neutron star or black hole.

I was surprised to see the supernova-only explanation promoted on a number
of suposedly authoritative web sites. Both processes are needed to form
elements above iron in the periodic table.

Wikipedia has introductions to all these concepts.

http://en.wikipedia.org/wiki/S-process

http://en.wikipedia.org/wiki/R-process

http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis

http://en.wikipedia.org/wiki/Stellar_nucleosynthesis (brief)

Do we know which supernova? Shouldn't it/they have left behind neutron
stars or black holes that we could see today?

That's the problem with black holes and neutron stars--they are very
difficult to see. Even if you could, you can't point to one and say, "That
one was the solar system's grandpappy." How could you tell?

Or is it more likely that many widely separated supernova contributed the
matter that makes up the earth, and so the earth has many "parent" stars?


In fact the Earth formed only about 4.55 BY ago, and the Universe is much
older, 13.7 BY, so the element formation process in stars was going on for a
very long time, gradually building up the elements that make up Earth, Sun,
and Solar System. In that sense millions (billions...) of stars gave their
lives for you. Awesome.

--
Mike Dworetsky

(Remove pants sp*mbl*ck to reply)

"Mike Dworetsky" wrote in
:

"Peter Webb" wrote in message
u...
I am of the understanding that almost all of the elements heavier than
Helium - and specifically including the the elements that make up the
earth - were formed earlier in the lifetime of the Universe in stars
that supernova.


This is a commonly-held but erroneous view. Supernovae are by no
means the only source of heavy elements, though they are important.

Elements formed in the Big Bang include H, He, Li, and Be. Heavier
elements were (and still are) formed in stars and returned to the
interstellar medium where they are incorporated in new stars and
planets.

Elements from B through Fe (and Co and Ni) are formed in the interiors
of evolving stars through successive fusion stages that release
energy. Depending on the mass of the stars, this stops at different
stages. During this stellar evolution, at certain stages nuclear
reactions release neutrons that react with iron and other existing
heavy nuclei, slowly building up heavy elements (or certain isotopes
of heavy elements). This enriched material is released back into the
interstellar medium through stellar winds and production of planetary
nebulae.

Stars above a certain mass collapse at the end of iron-formation and
become Type II supernovae. During the moments of the
implosion-explosion and expansion, the matter is flooded with neutrons
and heavy elements are also formed rapidly (other isotopes--some
isotopes can be formed by both processes). This can end in formation
of a neutron star or black hole.

Cany you privode a link to a technical a reference supporting the
theopry that trans-ferric heavy elements are created with neutrons? I
have always been under the impression that they were created by
endothermic fusion reactions.

I was surprised to see the supernova-only explanation promoted on a
number of suposedly authoritative web sites. Both processes are
needed to form elements above iron in the periodic table.

Wikipedia has introductions to all these concepts.

http://en.wikipedia.org/wiki/S-process

http://en.wikipedia.org/wiki/R-process

http://en.wikipedia.org/wiki/Big_Bang_nucleosynthesis

http://en.wikipedia.org/wiki/Stellar_nucleosynthesis (brief)

Do we know which supernova? Shouldn't it/they have left behind
neutron stars or black holes that we could see today?

That's the problem with black holes and neutron stars--they are very
difficult to see. Even if you could, you can't point to one and say,
"That one was the solar system's grandpappy." How could you tell?

Or is it more likely that many widely separated supernova contributed
the matter that makes up the earth, and so the earth has many
"parent" stars?

In fact the Earth formed only about 4.55 BY ago, and the Universe is
much older, 13.7 BY, so the element formation process in stars was
going on for a very long time, gradually building up the elements that
make up Earth, Sun, and Solar System. In that sense millions
(billions...) of stars gave their lives for you. Awesome.

It's probably impossible to find our neutron star because the galaxy
orbits in such a way as to mix the material within it. No doubt our
star has made at least a couple of orbits around the galaxy, leaving
it's original place of origin so far behind that it might be impossible
to find again.

I also think that neutron stars without accretion disks may be
invisible. If it's just drifting loose somewhere, without a binary star
or a cosmic cloud to feed it a steady stream of gas, there'd probably be
no hope of trying to find it.

This question is a very incisive one, and often an impossible question
suggests a simpler one that can be answered. A more specific phrasing
might be to ask what happens if we do the following. Let's project
backwards the orbit of our star through the galaxy to the place and time
of it's origin, and then postulate that a typical stellar nursery
existed at that location, with it's typical gas cloud and maybe a
neutron star. If we then project that "nursery cluster" forward in time
to the present day, would it be completely distributed throughout the
galaxy, or would it occupy a localized region that could possibly be
searched for the neutron star.

I don't know what is the state of the art on the issue of galactic
mixing, but I suspect that it's not very well advanced at all. And then
there's the general question of what are the general dynamics of stars
after they leave stellar nurseries, and what happens to the gas cloud
from which they formed. Leaving the neutron star unaccounted for, that
also asks the question, what happened to all the other sister stars,
that were born into our stellar nursery, and are they still nearby us?

I think that the OP asked a really good question, and if it is stated
that the question is too complex to answer, evidence should be shown to
support that assertion.

The original question has also raised another interesting variation.
Can a lone, dark neutron star, floating free in the galaxy, suddenly
come upon an Oort body and absorb it? If so, what kind of signal will
be observed, and if not, why can't it happen?